Influence of individual trim items on the acoustic behavior of the car interior Master’s Thesis in the Master’s programme in Sound and Vibration BRANISLAV IVANOV TEIK HUAT ONG Department of Civil and Environmental Engineering Division of Applied Acoustics Vibroacoustics Group CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2007 Master’s Thesis 2007:149 ISSN 0283-8338 MASTER’S THESIS 2007:149 Influence of Individual Trim Items on the Acoustic Behavior of the Car Interior Teik Huat, Ong Branislav, Ivanov Department of Civil and Environmental Engineering Division of Applied Acoustics Vibroacoustics Group CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden 2007 Influence of Individual Trim Items on the Acoustic Behavior of the Car Interior c© Teik Huat, Ong and Branislav Ivanov, 2007 Master’s Thesis 2007:149 Department of Civil and Environmental Engineering Division of Applied Acoustics Vibroacoustics Group Chalmers University of Technology SE-41296 Göteborg Sweden Tel. +46-(0)31 772 1000 Reproservice / Department of Civil and Environmental Engineering Göteborg, Sweden 2007 Influence of individual trim items on the acoustic behavior of the car interior Master’s Thesis in the Master’s programme in Sound and Vibration Teik Huat, Ong Branislav, Ivanov Department of Civil and Environmental Engineering Division of Applied Acoustics Vibroacoustics Group Chalmers University of Technology Abstract The accuracy of predicting the vibro-acoustic response of the car bodies, and in particularly, the accuracy of predicting the NTF (Noise Transfer Function or p/F, the acoustic response measured with microphone due to mechanical excitation on the body) has always been a hot topic. This master thesis project was aimed at measuring or generating valuable test data regarding the ef- fect of selected trim items on the response characteristics, that could be used in identifying the problem areas for CAE models. Measurements with both A-FRFs - acoustical excitation (loudspeaker in the cavity) - and NTFs - mechanical excitation (impact hammer) - were carried out for several trim levels on a Body- in-Blue (Body-in-Prime with trimmed closures). Both acoustic response (microphones) and structural response (acc) were collected. The configurations under test included: empty cavity, cavity with carpets only, cavity with front seats only and etc, until the cavity with IP, front & rear seats, parcel shelf trim & carpets. The changes in response incurred by particular items were identified and the data prepared will be used to make comparisons with the CAE analysis results. Keywords: A-FRF, A-MTF, NTF, VTF, Acoustical excitation, Mechanical excitation. iii CHALMERS, Master’s Thesis 2007:149 CHALMERS, Master’s Thesis 2007:149 iv Contents Abstract iii Contents iv Acknowledgements vii 1. Introduction 1 1.1. Project Background and Objectives . . . . . . . . . . . . . . . . . . . . . . . . 1 2. Basic Principles 3 2.1. Theoretical Background and Comparison . . . . . . . . . . . . . . . . . . . . 3 3. Vehicle Trim Configurations Investigation and Result 7 3.1. General Setup and Vehicle Trim Configurations . . . . . . . . . . . . . . . . . 7 3.2. Measurement by Acoustical Excitation . . . . . . . . . . . . . . . . . . . . . . 9 3.2.1. Setup and Methodology . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2.2. Quality of A-FRF and A-MTF measurements . . . . . . . . . . . . . . 12 3.2.3. A-FRF Results and Discussion on Empty Trim Configuration . . . . . 13 3.2.4. A-FRF Results and Discussion on Empty Trim Vs Rs Parcel Trim Con- figuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2.5. A-FRF Results and Discussion on Empty Trim Vs IP Trim Configuration 16 3.2.6. A-FRF Results and Discussion on Empty Trim Vs Full Trim Configuration 18 3.2.7. A-FRF Results and Discussion on All Trim Configuration at Driver’s Outer Ear. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.2.8. A-MTF Results and Discussion of the Roof . . . . . . . . . . . . . . . 21 3.2.9. A-MTF Results and Discussion on the Rear Window . . . . . . . . . . 23 3.2.10. A-MTF Results and Discussion on the Parcel Shelf . . . . . . . . . . . 25 3.2.11. Investigation on the 40Hz peak with mass-loading . . . . . . . . . . . 26 3.3. Measurement by Mechanical Excitation . . . . . . . . . . . . . . . . . . . . . 28 3.3.1. Setup and Methodology . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.3.2. Quality of NTF and VTF measurements . . . . . . . . . . . . . . . . . 31 3.3.3. NTF and VTF Data Representation Discussion . . . . . . . . . . . . . 32 3.3.4. NTF and VTF Influence of Trim Configurations at All Measurement Points from Back Suspension/Chassis Mounts Excitation (Z-Direction) 33 v 3.3.5. NTF Influence of Trim Configurations at Driver’s Outer Ear from All Excitation Points and Directions. . . . . . . . . . . . . . . . . . . . . . 34 3.3.6. NTF and VTF Influence of Carpet Trim at Driver’s Outer Ear and Wind- screen from Excitation Point 102 Z-Direction. . . . . . . . . . . . . . . 36 3.3.7. NTF and VTF Influence of IP Trim at Driver’s Outer Ear and Wind- screen from Excitation Point 102 Z-Direction. . . . . . . . . . . . . . . 37 4. Conclusion 39 5. Future Work 41 References 43 A. Measurement Setup Pictures and Plots 45 A.1. Vehicle Trim Parts Description . . . . . . . . . . . . . . . . . . . . . . . . . . 45 A.2. Acoustical Excitation and Measurement Positions . . . . . . . . . . . . . . . . 48 A.2.1. Loudspeaker Dimension and Position Co-ordinates . . . . . . . . . . . 48 A.2.2. Microphones Positions . . . . . . . . . . . . . . . . . . . . . . . . . . 49 A.2.3. Accelerometers Positions . . . . . . . . . . . . . . . . . . . . . . . . . 51 A.2.4. A-FRF Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 A.2.5. A-MTF Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 A.2.6. Mass-load investigation Plots . . . . . . . . . . . . . . . . . . . . . . 88 A.3. Mechanical Excitation and Measurement Positions . . . . . . . . . . . . . . . 89 A.3.1. Excitation Positions and Directions . . . . . . . . . . . . . . . . . . . 89 A.3.2. Measuremant Positions . . . . . . . . . . . . . . . . . . . . . . . . . . 91 A.3.3. NTF Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 A.3.4. VTF Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 B. Matlab GUI and Code 109 B.1. Acoustical Excitation Matlab Code . . . . . . . . . . . . . . . . . . . . . . . . 109 B.1.1. A-FRF Matlab Code . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 B.1.2. A-MTF Matlab Code . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 B.1.3. Mass-loading Matlab Code . . . . . . . . . . . . . . . . . . . . . . . . 120 B.2. Mechanical Excitation Matlab Code . . . . . . . . . . . . . . . . . . . . . . . 122 B.2.1. NTF and VTF Matlab Code . . . . . . . . . . . . . . . . . . . . . . . 122 CHALMERS, Master’s Thesis 2007:149 vi Acknowledgements We would like to express our deepest gratitude to our supervisor/mentor Andrzej Pietrzyk from Volvo Car Corporation (VCC), for the morale and technical support which he has continuously given us during the period of the master thesis project. Our fullest appreciation to our supervisor/professor Wolfgang Kropp for the technical support and assistance that enabled us for better root cause finding that eventually led us to resolve our technical issues in the master thesis project. And special thanks to researcher Patrik Andersson for his technical guidance and his patience whenever we faced any technical doubts. We would also like to thank Börje Wijk for his ever-patient assistance to us in terms of equip- ment setup issues and logistic problem before and after each measurement or experiment. Lastly, we would like to take this opportunity to express our utmost gratitude to our families and loved ones for their unconditional care and support. vii CHALMERS, Master’s Thesis 2007:149 viii 1. Introduction 1.1. Project Background and Objectives A simplified acoustic model is currently used in the industry as vehicle trim items are often disre- garded in vehicle cavity acoustic modeling. Carpets, and trim panels like parcel shelf, A,B,C(D) pillar covers are only considered as mass in the TB (trimmed body) vehicle models. And besides, bigger and heavier trim items like seats and IP are acoustically modeled in a relative simplified way in CAE (but structurally modeled in detail). The reason for it, as often mentioned, is that the acoustical influence on the vehicle cavity by most of the trim items is expected only at higher frequencies (>300Hz). The objective of the project is to investigate the acoustical influence of different trim items on the vehicle cavity. The experiments consider both acoustical excitation and mechanical excitation. The data analysis of interest is on the A-FRF (acoustical frequency response function), A-MTF (acoustical mechanical transfer function), VTF (vibration transfer function) and the NTF (noise transfer function) on a BIB (body in blue) Volvo S80 model. Lastly, the project serves as a feasibility study to enhance and validate the current cavity acoustics CAE prediction/simulation and hence to be used for future vehicle CAE prediction/simulation models. 1 CHALMERS, Master’s Thesis 2007:149 2 2. Basic Principles 2.1. Theoretical Background and Comparison The A-FRF (Acoustical Frequency Response Function) for a vehicle measures the acoustical behavior in the vehicle cavity when excited with a sound source. The vehicle cavity are assumed to be analogous to a room, as shown in figure 2.1 with a loudspeaker exciting below microphone position 1. Figure 2.1.: Vehicle cavity analogous to a room. The sound pressure over volume acceleration (p/q’) can be evaluated by equation (2.1). p q′ = ρ ∗ c2 ∗ ∞∑ n=0 ψn(x) ∗ ψn(y) Λn ∗ (ω2 n − ω2) (2.1) where: ω=2*π*f. p = sound pressure. q’ = volume acceleration for sound source (loudspeaker). rho = air density. ψn(x) = shape function for sound source (loudspeaker). ψn(y) = shape function for receiver (microphone). f = frequency. Λn = the normalization constant for the mode of order n. 3 However, the actual vehicle cavity is not ’ideal’ as in comparison to a room in two aspects: 1. The vehicle cavity walls are not rigid and are constructed by a combination of metal sheets, frame and windows which are susceptible to structural vibration and noise during measurement. 2. The vehicle cavity is not a rectangular shape relative to a room. Figure 2.2, 2.3 and 2.4 provides a comparison of the theoretical and actual measurement plot for the absolute, real and imaginary values. The results between theoretical and actual measurement show discrepancies due to the structural vibrations and noise on the vehicle when excited by the loudspeaker. Some thoughts should be considered to select an appropriate graphical representa- tion of the results to identify the resonance modes easily. Based on the real plots and imaginary plots, the phase change through the resonance region (modes) is clearly characterized by a sign change in one part (real) accompanied by a peak (maximum and minimum) value in the other part (imaginary). And the absolute plots (or levels) as well as the use of logarithmic scales is not feasible in this case because it is necessary to accommodate both positive and negative values, and this would be impossible with logarithmic axes. Overall, the imaginary plot is preferred in this project as the modes with phase are more effectively identified by the maximum and minimum peaks. (a) Theoretical Response. (b) Actual Measurement Response. Figure 2.2.: Comparison of absolute results between theoretical and actual measurement. CHALMERS, Master’s Thesis 2007:149 4 (a) Theoretical Response. (b) Actual Measurement Response. Figure 2.3.: Comparison of real results between theoretical and actual measurement. (a) Theoretical Response. (b) Actual Measurement Response. Figure 2.4.: Comparison of imaginary results between theoretical and actual measurement. 5 CHALMERS, Master’s Thesis 2007:149 A-MTF (Acoustical-Mechanical Transfer Function) measures the vibrational response with ac- celerometer(s) via acoustical excitation. The response is measured by the acceleration (vibra- tion) of the test point over the volume acceleration of the sound source (a/q’). An illustration of the A-MTF measurement is shown in figure 2.5(a). NTF (Noise Transfer Function) measures the sound pressure with microphones via mechanical excitation. Generally, it is the noise transfer path from the excitation point, through the vehicle body, air in the cavity and to the microphones. The response is measured by the sound pressure of the test point over the force of excitation (p/F). Whereas, VTF (Vibration Transfer Function) measures the vibration in terms of acceleration over the excitation force (a/F). An illustration of NTF and VTF are shown in figure 2.5(b). (a) A-MTF measurement by acoustical excita- tion. (b) NTF and VTF measurement by mechanical excitation. Figure 2.5.: Illustration of A-MTF, NTF and VTF measurement. CHALMERS, Master’s Thesis 2007:149 6 3. Vehicle Trim Configurations Investigation and Result 3.1. General Setup and Vehicle Trim Configurations All measurements were conducted in the Applied Acoustics Department at Chalmers University. The vehicle test object, which is the Volvo S80 BIB (Body-In-Blue with the car cavity obtained by sealing all accessories holes and mounting all doors and trunk hatch), was placed on three air mounts in order to obtain a free-free conditions. The places to rest the body on the air mounts (figure 3.1) were discussed and chosen by measurement in collaboration with the thesis work of Miguel Colomo. In the collaborative experiment, the measurement for a three-air-mounts support was compared with a four-air-mounts support and the results yielded no significant dif- ference between the two types of air mounts setup. Figure 3.1.: Air-mounts positions The measurements were performed on different trim configurations. The configurations were differed by the different trim parts (individual trim part or a combination of trim parts) installed to the BIB. The measurement and investigation of this master thesis project had been categorized into two sections based on the measurement excitation method: 1. Acoustical excitation. 2. Mechanical excitation. 7 For the acoustical excitation measurement, fourteen trim configurations had been selected and the experiment was performed with a loudspeaker as a source and the responses were measured with microphones (A-FRF) and accelerometers (A-MTF). Whereas for the mechanical excitation measurement, six configurations had been selected and the experiment was performed with an impact hammer as a source and the responses were also measured with microphones (NTF) and accelerometers (VTF). An overall description can be presented by tables 3.1 and 3.2. Table 3.1.: Experiment overview. Items Acous. Excitation Mech. Excitation Measurement A-FRF, A-MTF NTF, VTF Microphone positions 61 6 Accelerometers positions x direction(s) 3x1 9x1 Trim configurations 14 6 Excitation point(s) and direction(s) 1x1 17x3 Table 3.2.: Measured trim configurations with ’x’. Trim Configurations Acous. Excitation Mech. Excitation Empty x x Rear seats (Rs) x x Front seats (Fs) x Carpets (Cpts) x IP x Rs and Parcel x x Fs, Rs and Parcel x Fs, Rs, Cpts and Parcel x IP and Rs x IP and Fs x IP and Cpts x IP, Rs and Parcel x x IP, Rs, Cpts and Parcel x IP, Fs, Rs and Parcel x IP, Fs, Rs, Cpts and Parcel x x CHALMERS, Master’s Thesis 2007:149 8 3.2. Measurement by Acoustical Excitation 3.2.1. Setup and Methodology The schematic of the measurement setup for the acoustical excitation measurement is shown in figure 3.2. In this part of the experiment, a loudspeaker was used as a source to excite the modes in the cavity. White noise, acquired from the VXI acquisition system was used as the output signal for the loudspeaker and an equalizer was connected in order to obtain a flat response over the frequencies of interest as much as possible. The loudspeaker was placed on the passenger cabin floor of the vehicle facing the fire-wall (refer to appendix A.2.1 for the actual position). An accelerometer was placed on the loudspeaker membrane to measure the volume of acceleration (q’) and in addition, the signal from the accelerometer was also taken as a reference signal. Figure 3.2.: Acoustical excitation measurement setup. The measurement responses of interest were A-FRF and A-MTF and all the test equipment used for this experiment are shown in table 3.3. 9 CHALMERS, Master’s Thesis 2007:149 Table 3.3.: Test equipment for A-FRF and A-MTF measurement. Item Equipment Manufacturer Model S/N Sensitivity 1 Microphones Panasonic WM-063 n/a 1V/µbar 2 Uni-axial Acc. Brüel & Kjaer 4393V 2197929 0.3104 pC/ms−2 3 Charge Amplifier Brüel & Kjaer 2635 986722 n/a 4 Acquisition Station Agilent Tech. n/a n/a n/a 5 Mic. preamplifier Chalmers Uni. n/a n/a n/a 6 Stereo Graphic Equalizer Technics SH-8065 MB65263008 n/a 7 Stereo Amplifier NAD 302 T302N11523 n/a 8 Loudspeaker Chalmers Uni. n/a n/a n/a The measurement of A-FRF describes the acoustical modes formation in the vehicle cavity in accordance to the frequencies. The precise description of the modes formation can be achieved by placing arrays of microphones at as different locations as possible in the vehicle. Each mi- crophone array contained a certain number of microphones, which can be shown in table 3.4. Table 3.4.: Microphone arrays in the cavity. Mic. arrays No.of mic Position in cavity Longitudinal cabin 8 Front window to parcel shelf. Longitudinal parcel 4 Front parcel to rear window. Lateral front seats 8 Driver to fr. passenger outer ear. Lateral rear seats 8 Left rear passenger to right rear passenger outer ear. Lateral parcel 8 Left side to right side of parcel shelf. Vertical cabin 6 Roof to vehicle ’tunnel shaft’. Pedals 1 Pedals at driver’s feet. Longitudinal trunk 6 Longitudinal far end of the trunk above the spare tyre cavity. Lateral trunk 7 Lateral far end of the trunk above the spare tyre cavity. Vertical trunk 5 Parcel shelf to the bolts for the spare tyre. The longitudinal arrays refer to the microphones placed along the x-axis of the vehicle, whereas the lateral arrays and the vertical arrays refer to the microphones placed along the y-axis and z-axis respectively. An illustration of the microphone arrays positions is also shown in figure 3.3 and the actual photographs are shown in appendix A.2.2 for reference. CHALMERS, Master’s Thesis 2007:149 10 Figure 3.3.: Microphones array positions in the vehicle cavity. Whereas, the measurement of A-MTF were performed on certain parts of the vehicle that were considered to have relatively higher influence on the acoustical levels inside the cavity. Hence, uni-axial accelerometers for the A-MTF measurement were placed on: • Roof • Parcel shelf • Rear window The actual photographs of the uni-axial accelerometers and positions are also shown in appendix A.2.3. All A-FRF and A-MTF measurement were performed on all fourteen trim configurations. The trim configurations for the acoustical excitation measurement is shown in the previous table 3.2. 11 CHALMERS, Master’s Thesis 2007:149 3.2.2. Quality of A-FRF and A-MTF measurements Based on figure 3.4(a), the flat frequency response of the loudspeaker is indicated by the au- tospectra of the accelerometer situated on the loudspeaker cone. The position of the accelerom- eter is clearly shown in appendix A.2.1. The comparison between the background noise and measurement from a microphone position is also shown in figure 3.4(b) with SNR ranging from around 2dB to 60dB as the frequency increases. (a) Autospectra of the accelerometer response on the loudspeaker. (b) Autospectra between background noise and mi- crophone measurement. Figure 3.4.: Loudspeaker response (accelerometer) and background noise measurement. The A-FRF and A-MTF measurement coherences (empty trim configuration) in figure 3.5 demon- strate that the measurement quality is maintained between 20Hz and 1250Hz. (a) Coherence of microphone response (A-FRF) at the pedals position. (b) Coherence of accelerometer response (A-MTF) at the parcel shelf position. Figure 3.5.: Coherences of A-FRF and A-MTF for empty trim configuration. CHALMERS, Master’s Thesis 2007:149 12 3.2.3. A-FRF Results and Discussion on Empty Trim Configuration The discussion of interest for this section primarily revolves on the longitudinal modes formed in the vehicle cavity as well as comparison results on different trim configurations (mainly empty trim configuration in comparison to other trim configurations) were selected for discussion. The longitudinal modes has been mainly selected for discussion due to the relation of the mode to the ’booming’ noise in the vehicle cabin. The comparison result of selected different trim con- figurations are useful in providing the understanding of how each or a combination of trim items influence the acoustical response in the vehicle cabin. Besides the A-FRF results discussion in the following sections, A-FRF measurement plots for other acoustical modes with the respective trim configurations are also shown in appendix A.2.4. The acoustical response or A-FRF of an empty trim configuration can be observed in figure 3.6 where the response from all microphones along the longitudinal array is shown. Based on the figure, the first mode is located at around frequency 65Hz, whereas the second and third longitudinal modes are located at around frequency 100Hz and 148Hz respectively. Figure 3.6.: All microphones response along the longitudinal array for empty trim configuration. To simplify the plots, the acoustical modes can also be clearly plotted by two far end micro- phones (from mic 55 at the trunk to mic 12 at the front window) as shown in figure 3.7. The simplified plots will be used frequently in further comparison results and discussion. Besides the identified acoustical modes in this experiment, an unexpected acoustical response was also 13 CHALMERS, Master’s Thesis 2007:149 observed around 40Hz. The unexpected response was further investigated and the result will be discussed in section 3.2.11. Figure 3.7.: Two far-end microphones response along the longitudinal array for empty trim configuration. In addition, the acoustical mode shape for the first, second and third mode can also be shown in figure 3.8 and figure 3.9. Hardly any changes observed in the lateral and vertical arrays and the response for the modes corresponds well with the room modal analysis theory. (a) First acoustical mode shape at 65Hz. (b) Second acoustical mode shape at 100Hz. Figure 3.8.: First and second acoustical mode shape for empty trim configuration. CHALMERS, Master’s Thesis 2007:149 14 Figure 3.9.: Third acoustical mode shape for empty trim configuration at 148Hz. 3.2.4. A-FRF Results and Discussion on Empty Trim Vs Rs Parcel Trim Configuration This section contains the result comparison and discussion between the empty trim and rs parcel trim configuration. Installing the rs (rear seats) and the parcel shelf trim actually separates or decouples the passenger cabin and the vehicle trunk. Figure 3.10 shows the comparison longitudinal response for an empty trim to the rs parcel trim configuration. The first longitudinal mode has been shifted to a higher frequency (from 65Hz to 85Hz) due to the fact that by adding the rs parcel trim items, the length of the vehicle cavity has become smaller. Figure 3.10.: First longitudinal mode comparison for empty vs rs parcel trim configuration. Figure 3.11 shows the first longitudinal mode shape at 85Hz in the passenger cabin. Minimal acoustical response or changes is captured at the vehicle trunk due to the sealing by the rear seats and parcel shelf trim. 15 CHALMERS, Master’s Thesis 2007:149 Figure 3.11.: First longitudinal mode shape for rs parcel trim configuration at around 85Hz. 3.2.5. A-FRF Results and Discussion on Empty Trim Vs IP Trim Configuration The vehicle IP is the biggest and heaviest trim part in the experiment. The first longitudinal mode comparison between empty trim and ip trim configuration is shown in figure 3.12(a). Surprisingly, adding the vehicle IP actually decreases the longitudinal mode frequency instead of increasing the mode frequency as it was initially expected that the IP would occupy the space and make the cavity length shorter. Another suspicion of this phenomena was due to the reason that the air cavities below the IP was not sealed, allowing the air and sound to curve and travel freely into the cavity. The sound field that curves and travels into the air cavity below the IP indicates a ’longer’ propagating path, which could explain the decrement at the longitudinal frequency mode. (a) First longitudinal mode comparison for empty vs ip trim configuration. (b) First longitudinal mode comparison after sealing IP. Figure 3.12.: Acoustical influence on longitudinal mode with IP trim configuration. CHALMERS, Master’s Thesis 2007:149 16 However, the same phenomena is still observed as shown in figure3.12(b) after sealing the air cavities below the IP with mineral wools and damping layers (figure 3.13). Figure 3.13.: IP lower cavities sealed with damping layer and mineral wool. The phenomena can be further investigated by the impedance changes. The vehicle cavity wall can be assumed to be analogous to a mass-spring system, as shown in figure 3.14. Figure 3.14.: The vehicle cavity wall analogous to a mass-spring system. The mass and spring parameters can be simulated by a negative or positive imaginary impedance (Z) and the changes of the frequency mode with impedance can be observed by the plot in figure 3.15. Based on the plot, an increasing imaginary values (less negative) of the impedance decreases the frequency mode which indicates a heavier mass and softer surface like the vehicle IP would lower the frequency mode in the vehicle cavity. 17 CHALMERS, Master’s Thesis 2007:149 Figure 3.15.: Frequency mode changes in response to impedance changes. 3.2.6. A-FRF Results and Discussion on Empty Trim Vs Full Trim Configuration The term full trim configuration in this context indicates a combination of IP, front seats , rear seats, carpets and parcel trim. Figure 3.16 shows the comparison between the empty trim and full trim configuration. Based on the figure, it is observed that despite the increase of the longitudinal mode frequency (basically due to the decoupling of the passenger cabin and trunk), there is also significant damping to the acoustical response incurred by the full trim parts relative to a empty cavity. Figure 3.16.: Acoustical influence on longitudinal mode with full trim configuration. CHALMERS, Master’s Thesis 2007:149 18 3.2.7. A-FRF Results and Discussion on All Trim Configuration at Driver’s Outer Ear. This section shows and discuss the influence of the trim configurations to the driver’s outer ear. The discussion basically divided the trim configurations in 3 groups: individual trim configura- tion, all trim configurations with rs parcel and all trim configurations with IP. Based on figure 3.17, the influence of each trim parts varies. The carpets shows a smoother and damped characteristic throughout the frequency range relative to other trims. Installing the front seats shows higher influence with a dip at around 350Hz and lower sound pressure level from 900Hz onwards. Both the rear seats and rs parcel configuration indicates a similar response and it is observed that the two trim configurations actually increase the sound pressure level from 700Hz onwards. Whereas for the IP trim configuration, a significant drop of sound pressure for around 20dB is recorded at from 300Hz to 600Hz. In general, the significant influence at 300Hz to 600Hz is dominated by the IP trim configuration. While from 700Hz onwards, the significant influence is mainly dominated by the rear seats and rs parcel trim configurations relative to the empty trim configuration. Figure 3.17.: All individual trim configurations with reference to empty trim configuration at driver’s outer ear. Figure 3.18 is selected to observe the influence of the trim items when the passenger cabin is decoupled from the trunk by the rs parcel trim configuration. As expected, the effect is similar to figure 3.17 and the significant influence is recorded whenever the IP is part of the trim con- figurations. In addition, the carpets still acts as a good damping item to smoothen the response in the cavity. 19 CHALMERS, Master’s Thesis 2007:149 Figure 3.18.: All Rs Parcel trim configurations with reference to empty trim configuration at driver’s outer ear. Figure 3.19 shows that all trim configurations with IP significantly decrease the sound pressure level throughout almost all the frequency of measurement relative to empty trim configuration. Figure 3.19.: All IP trim configurations with reference to empty trim configuration at driver’s outer ear. Lastly a more detailed numerical representation in shown in table 3.5. All values are shown in sound pressure dBA levels. The delta is the difference between the empty trim and the trim of interest. Based on the standard deviation, it is observed that the dispersion of the sound pressure level is higher and higher frequencies for different trim configurations. It is clearly shown that the the trim configuration with IP dominantly decreases the sound pressure level from 4.5dBA to 8.6dBA. However, the rear seats and rs parcel trim configuration increase the sound pressure level of 2.6dBA and 2.8dBA to the vehicle cavity. CHALMERS, Master’s Thesis 2007:149 20 Table 3.5.: Influence of trim configurations in sound pressure levels, Lp (dBA) at driver’s outer ear. 25-50 Hz 50-250 Hz 250-1250 Hz Total dBA Trim configuration Actual Delta Actual Delta Actual Delta Actual Delta Empty 63.2 0.0 93.1 0.0 100.1 0.0 100.9 0.0 Carpets (Cpts) 62.8 0.4 93.2 -0.1 97.4 2.7 98.8 2.1 Front seats (Fs) 63.9 -0.7 94.1 -1.0 98.6 1.5 99.9 1.0 Rear seats (Rs) 65.8 -2.6 95.7 -2.5 102.9 -2.8 103.7 -2.8 IP 64.0 -0.8 92.1 1.0 94.4 5.7 96.4 4.5 Rs Parcel(Prcl) 66.3 -3.1 94.9 -1.8 102.8 -2.8 103.5 -2.6 Fs Rs Prcl 66.9 -3.7 95.8 -2.7 100.2 -0.1 101.5 -0.7 Fs Rs Cpts Prcl 66.7 -3.5 94.8 -1.7 93.8 6.3 97.4 3.5 IP Cpts 63.3 -0.1 88.8 4.3 89.7 10.3 92.3 8.6 IP Fs 64.3 -1.1 90.8 2.3 93.9 6.2 95.6 5.3 IP Rs 65.7 -2.5 90.3 2.8 91.5 8.6 94.0 6.9 IP Rs Prcl 66.1 -2.9 90.1 3.0 92.2 7.8 94.3 6.6 IP Fs Rs Prcl 66.7 -3.5 90.8 2.4 93.6 6.4 95.5 5.4 IP Fs Rs Cpts Prcl 66.8 -3.6 89.1 4.1 89.8 10.3 92.5 8.4 Average 65.2 92.4 95.8 97.6 Standard deviation 1.5 2.4 4.5 3.8 3.2.8. A-MTF Results and Discussion of the Roof This section shows the A-MTF results and comparison discussion between the empty trim and other selected trim configurations of the vehicle cavity roof. Figure 3.20(a) illustrates the first A-MTF measurement comparison on the empty trim with the RS Parcel trim configurations. The discrepancies can be seen starting from around 45Hz and both the measurement deviate higher as the frequency goes higher. Adding the trims may be similar to adding mass and damping to the vibrating structure where the resonance shift can be observed from the measurement comparison (based on the anti-resonance shift from around 65Hz to 80Hz) as well as the resonance modes are seen to be lower and damped (more spread out). 21 CHALMERS, Master’s Thesis 2007:149 (a) Roof vibration for Empty vs Rs Parcel configura- tion. (b) Roof vibration for Empty vs IP configuration. Figure 3.20.: Comparison between Empty vs Rs Parcel configuration and Empty vs IP configuration for roof vibration. The resonance shift and damping effect can also be clearly seen by the IP trim configuration and the effect is highest for the full trim configuration, based on figure 3.20(b) and figure 3.21, due to the higher amount of mass and damping characteristic imposed from the two trim configurations. Figure 3.21.: Comparison between Empty vs Full configuration for roof vibration. CHALMERS, Master’s Thesis 2007:149 22 3.2.9. A-MTF Results and Discussion on the Rear Window In this section, a comparison on the empty trim and rs parcel is initially performed for the rear window A-MTF measurement, which is shown in figure3.22(a). As it is recalled, installing the rs parcel trim actually makes the length of vehicle cavity smaller and subsequently increases the frequency of the first longitudinal acoustic resonance mode. A similar behavior is also observed at the A-MTF of the rear window the comparison is shown in figure 3.22. This is interesting as the significant changes in the rear window follows the changes in the longitudinal acoustic changes in the vehicle cavity. This may indicate the rear window is relatively sensitive (compared to roof and parcel shelf) to the longitudinal modes as the sound pressure of the mode is incidently hitting the rear window. (a) A-MTF for rear window. (b) A-FRF for mic 1. Figure 3.22.: A-MTF rear window and A-FRF mic 1 on empty vs rs parcel trim configuration. Whereas there are less discrepancies in the A-MTF for the empty and IP comparison and in- stalling the IP does not yield much resemblance with the A-FRF at this frequency range, as shown in fig 3.23(a). In previous A-FRF discussion, installing the IP decreases the frequency of the first longitudinal mode. A similar characteristic is also observed in the A-MTF measurement, as shown in figure 3.23(b) although the effect is not obvious. 23 CHALMERS, Master’s Thesis 2007:149 (a) A-MTF for rear window. (b) A-FRF for mic 1. Figure 3.23.: A-MTF rear window and A-FRF mic 1 on empty vs ip trim configuration. Lastly, the empty trim vs full trim configuration shows a resemblance with the empty trim vs rs parcel trim configuration as the adding the rs parcel trim yielded a more dominant changes or influence to the vibration of the rear window. (a) A-MTF for rear window. (b) A-FRF for mic 1. Figure 3.24.: A-MTF rear window and A-FRF mic 1 on empty vs full trim configuration. CHALMERS, Master’s Thesis 2007:149 24 3.2.10. A-MTF Results and Discussion on the Parcel Shelf The vibrational response of the parcel shelf for empty, rs parcel, ip and full configuration can be seen in this section. In figure 3.25(a) the comparison between empty and rs parcel configuration is shown. Both curves are following the same trend with small discrepancies in the levels which is due more mass is induced to the parcel shelf trim. (a) Parcel vibration for Empty vs Rs Parcel trim con- figuration. (b) Parcel vibration for Empty vs IP trim configura- tion. Figure 3.25.: Comparison between Empty vs Rs Parcel trim configuration and Empty vs IP trim config- uration. Whereas in figure 3.25(b), the comparison of the empty and ip configuration is observed. In this measurement comparison, the discrepancies in terms of levels and resonance mode shift is low. Even though the IP is the trim item with the biggest mass, the influence on the vibrational response (A-MTF) of the parcel shelf is minimal. Figure 3.26.: Comparison between Empty vs Full trim configuration Lastly in figure 3.26 for the empty vs full trim comparison, a similar phenomena or effect can 25 CHALMERS, Master’s Thesis 2007:149 be observed which is due to the increased damping and mass contributed by the total trim items in the configuration. Other A-MTF measurement plots are also shown in appendix A.2.5. 3.2.11. Investigation on the 40Hz peak with mass-loading In this section, an investigation to determine the origin of the 40Hz peak was conducted. The 40Hz peak was observed in the initial stage of the project and is mentioned in section 3.2.3 as a structural influence. In order to validate and determine the source of the structural influence, the investigation involved mass-loading selectively and separately the parts that could have the highest influence in the acoustical field in the vehicle cavity: the roof, parcel shelf and the rear window. The mass-loading experiment was performed by placing sandbags (roughly 30kg) on the vehicle parts of interest, which is shown in figure 3.27. Figure 3.27.: Mass-loading the rear window with sandbags. The investigation and measurement were conducted during the front seats trim was mounted inside the vehicle cavity. Figure 3.28(a) and figure 3.28(b) shows the respective A-FRF and A-MTF comparison measurement results after mass-loading. CHALMERS, Master’s Thesis 2007:149 26 (a) Mass loading effect on acoustic longitudinal mode. (b) Mass loading effect on roof vibration. Figure 3.28.: Mass-loading investigation on A-FRF and A-MTF. From these figures, it can be clearly observed that the 40Hz peak is mainly influenced by the rear window, due to the significant decrease in sound pressure and vibration. The rear window is rel- atively sensitive to the acoustical excitation and the mutual influence (between the rear window structure and acoustical excitation) generated the 40Hz peak in the form of sound and structural vibration which are captured by the microphones (mic 1 and mic 12) and the accelerometer on the roof. Besides the discussed investigation results, other mass-loading measurement plots can also be found in appendix A.2.6 for reference. 27 CHALMERS, Master’s Thesis 2007:149 3.3. Measurement by Mechanical Excitation 3.3.1. Setup and Methodology Figure 3.29 shows the equipment setup schematic for the NTF measurement on the BIB. All IEPE accelerometers are connected directly to the acquisition system except for an accelerome- ter at point:012 (which is a different accelerometer type and the output is amplified by a charge amplifier). The reason for this setup is the channels supply settings of the acquisition system has to be setup in groups of four (16 channels: 8 non-IEPE and 8 IEPE) and one non-IEPE accelerometer has to be chosen for this measurement. Figure 3.29.: Equipment setup for NTF measurement. Table 3.6 shows shows the test equipment for the NTF measurement channels and table 3.7 shows the mapping of the acquisition system to the measurement points on the BIB. CHALMERS, Master’s Thesis 2007:149 28 Table 3.6.: Test equipment for NTF measurement. Item Equipment Manufacturer Model S/N Sensitivity Exc/Meas Pos. 1 Impact Hammer Brüel & Kjaer 8200 1225726 *0.85 pC/N Exc. Caps 2 Microphone Panasonic WM-063 n/a 1V/µbar Point:001 3 Microphone Panasonic WM-063 n/a 1V/µbar Point:002 4 Microphone Panasonic WM-063 n/a 1V/µbar Point:003 5 Microphone Panasonic WM-063 n/a 1V/µbar Point:004 6 Microphone Panasonic WM-063 n/a 1V/µbar Point:005 7 Microphone Panasonic WM-063 n/a 1V/µbar Point:006 8 Uni-axial Acc. Brüel & Kjaer 4393 1600112 0.321 pC/ms−2 Point:012 9 Uni-axial Acc. Brüel & Kjaer 4507 30245 9.798 mV/ms−2 Point:606 10 Uni-axial Acc. Brüel & Kjaer 4507 30847 9.702 mV/ms−2 Point:627 11 Uni-axial Acc. Brüel & Kjaer 4507 30848 9.832 mV/ms−2 Point:641 12 Uni-axial Acc. Brüel & Kjaer 4507 30856 10.06 mV/ms−2 Point Mob 13 Uni-axial Acc. Brüel & Kjaer 4507 30850 9.848 mV/ms−2 Point:638 14 Uni-axial Acc. Brüel & Kjaer 4507 30853 9.960 mV/ms−2 Point:635 15 Uni-axial Acc. Brüel & Kjaer 4507 30854 9.787 mV/ms−2 Point:616 16 Uni-axial Acc. Brüel & Kjaer 4507 30855 9.775 mV/ms−2 Point:112 17 Charge Amplifier Brüel & Kjaer 2635 986722 n/a n/a 18 Acquisition Station Agilent Tech. n/a n/a n/a n/a 19 Mic. preamplifier Chalmers Uni. n/a n/a n/a n/a * Please take special note that the sensitivity of the B&K impact hammer used in the experiment contains the sensitivities for the force transducer and the hammer handle (factor 4.75). Table 3.7.: Acquisition system channels mapping and description. Channel Exc/Meas Position Description 1 Impact Hammer Excited on the cap fixtures. 2 Point:001 Driver outer ear. 3 Point:002 Pedals 4 Point:003 Front passenger outer ear. 5 Point:004 Rear right passenger outer ear. 6 Point:005 Parcel shelf. 7 Point:006 Trunk. 8 Point:012 Driver seat left front mount. 9 Point:606 Windscreen. 10 Point:627 Rear window. 11 Point:641 Parcel shelf. 12 Point Inertance Acc. on the excitation cap fixtures. 13 Point:638 Rear floor front. 14 Point:635 Front floor rear. 15 Point:616 Roof 16 Point:112 Front bumper. 29 CHALMERS, Master’s Thesis 2007:149 Photographs of the measurement positions be found in appendix A.3.2. Table 3.8 shows the excitation cap fixtures and the respective excitation directions for the NTF measurement a picture of an excitation cap with a hammer for point inertance measurement is shown in figure 3.30. Other photographs of excitation cap fixtures and excitation positions/direction are also shown in appendix A.3 for reference. Table 3.8.: Impact hammer excitation cap fixtures. Item Exc. Cap Fixtures Exc. Direction Description 1 Body:101 −X,+Y,+Z Front left chassis mount 2 Body:102 +X,−Y,+Z Front left chassis mount 3 Body:141 −X,+Y,−Z Front left suspension mount. 4 Body:201 +X,−Y,+Z Front right chassis mount 5 Body:202 +X,+Y,+Z Front right chassis mount 6 Body:205 +X,+Y,−Z Engine mount. 7 Body:241 +X,−Y,−Z Front right suspension mount. 8 Body:301 −X,+Y,+Z Back left chassis mount. 9 Body:302 −X,+Y,+Z Back left chassis mount. 10 Body:321 −X,−Y,+Z Back left chassis mount. 11 Body:341 −X,+Y,+Z Back left absorber mount. 12 Body:401 −X,−Y,+Z Back right chassis mount. 13 Body:402 +X,−Y,+Z Back right chassis mount. 14 Body:421 −X,+Y,+Z Back right chassis mount. 15 Body:441 −X,−Y,+Z Back right absorber mount. 16 Body:901 −X,−Y,−Z Engine mount. 17 Body:902 +X,−Y,−Z Engine mount. Figure 3.30.: Cap fixture with an impact hammer for point inertance measurement. All NTF and VTF measurement were performed on all six trim configurations. The trim config- urations for the acoustical excitation measurement is shown in previous table 3.2. CHALMERS, Master’s Thesis 2007:149 30 3.3.2. Quality of NTF and VTF measurements Figure 3.31 shows the autospectra of the force when excited by the impact hammer (rubber tip). As expected, it can be observed that the magnitude of the force drops significantly (around 10dB when reaches 600Hz) due to the poor energy distribution from a rubber hammer tip at higher frequencies. Figure 3.31.: Autospectra of the force from the impact hammer. Hence, the quality of the measurement can be investigated from the NTF and VTF coherences shown in figure 3.32(a) and 3.32(b). The coherences indicate that the measurement starts to deteriorate at around 600Hz which leads to measurement confidence level only from 20Hz to 600Hz. (a) Coherence of microphone response (NTF) at the driver’s outer ear. (b) Coherence of accelerometer response (VTF) at po- sition 012. Figure 3.32.: Coherences of NTF and VTF for empty trim configuration excited at cap fixture 201 z- direction. 31 CHALMERS, Master’s Thesis 2007:149 3.3.3. NTF and VTF Data Representation Discussion Extensive measurement was performed and a large database of measurement data (NTF and VTF) was collected in this part of experiment. The results and discussion selected in this section will be on four parts: 1. The influence of trim configurations to all measurement points (microphones and ac- celerometers) when mechanically excite at one excitation direction and excitation mount group (back suspension and chassis mounts) with a hammer. 2. The influence of trim configurations to one measurement point (driver’s outer ear) when mechanically excite at all excitation points and directions with a hammer. 3. The influence of the carpet trim to one NTF and VTF measurement point when mechani- cally excite at one excitation point z-direction. 4. The influence of the IP trim to one NTF and VTF measurement point when mechanically excite at one excitation point z-direction. Figure 3.33.: Non-averaged results of response at driver’s outer ear excited at all points and directions as well illustration of the average groups by the dotted squares. CHALMERS, Master’s Thesis 2007:149 32 The plots or data presented are averaged into three categories based on the excitation mounts: engine mounts, front suspension/chassis mounts and back suspension/chassis mounts. The aver- age of the plots will be relatively strategic to discuss and clearer to visualize the influence of the trim configurations. The non-averaged results or plots for the response at driver’s outer ear can be shown in figure 3.33. The dotted squares indicates the averaging categories that are imposed for further discussion plots. And finally, besides the selected NTF and VTF measurement results discussion in the following sections, other NTF and VTF measurement results can also be found in appendix A.3.3 and A.3.4. 3.3.4. NTF and VTF Influence of Trim Configurations at All Measurement Points from Back Suspension/Chassis Mounts Excitation (Z-Direction) The discussion of interest lies on how the six trim configurations influence the response of all fifteen measurement points when excitation is induced at the back suspension/chassis mounts (z-direction), which is shown in figure 3.34. Figure 3.34.: All measurement result excited at back suspension/chassis mounts (z-direction). Based on the figure, a systematic trend of the influence of the trim configurations is observed on the measurement results. It obvious at point 012 VTF (the measurement point below the driver 33 CHALMERS, Master’s Thesis 2007:149 front seat), the more trim item is added, the lower the vibration become. The trim items, es- pecially the rear seats, effectively barricade the noise coming from the back suspension/chassis mounts as it can be clearly seen from the NTF results at point 001 to point 006. However, there are measurement points that are less sensitive to the trim configurations, eg: point 112 (front bumper), point 606(front window) and point 616 (roof). The reason could be due to good vibration isolation of the structure and the vibration has been effectively damped before reaching the measurement points. 3.3.5. NTF Influence of Trim Configurations at Driver’s Outer Ear from All Excitation Points and Directions. In this section, a numerical description of the influence of trim configurations at the driver’s outer ear is shown in table 3.9. Based on the average in the table, it can be observed that the noise induced by the engine mounts is relatively higher than the noise induced by the front suspen- sion/chassis mounts and back suspension/chassis mounts. It indicates that the passenger cabin is more susceptible to noise induced by the engine mounts. The standard deviations shows that the influence of the trim configurations demonstrates the highest influence at the back suspen- sion/chassis excitation. The influence of the trim configurations at the engine mounts (especially the x-direction) seems to show similar characteristic with the A-FRF response at the driver’s ear, which installing the rear seats and rs parcel actually increases the noise level while IP dominantly decreases the noise. The effect of the trim configurations varies with the excitation directions. It can be clearly seen that depending on the direction for full trim at back suspension/chassis mounts excitation, the effect may range from 6.1dBA (x-direction) to 12.6dBA (y-direction) Generally, the influence of the trim configurations in this context is dependent on the direction and the place of excitation. CHALMERS, Master’s Thesis 2007:149 34 Table 3.9.: Influence of trim configurations in sound pressure levels, Lp (dBA) at driver’s outer ear excited at all excitation points and direction with frequency range from 20-600Hz. Engine Mounts Front Suspension / Chassis Mounts X Y Z X Y Z Trim configuration Actual Delta Actual Delta Actual Delta Actual Delta Actual Delta Actual Delta IP Fs Rs Parcel Carpets 69.0 1.3 78.8 3.7 75.4 3.1 67.2 5.2 70.1 6.7 71.8 4.7 IP Rs Parcel Carpets 69.1 1.2 78.7 3.9 75 3.5 67.2 5.2 72.1 4.7 71.5 5.0 IP Rs Parcel 70.3 0.0 79.1 3.4 76 2.6 69 3.4 74.9 1.9 74.9 1.6 Rs Parcel 71.8 -1.5 82.7 -0.2 78.1 0.5 70.1 2.3 77.5 -0.7 75.5 1.0 Rear seats 71.6 -1.3 81.1 1.4 77.4 1.2 71.4 1.1 76.5 0.3 74.9 1.6 Empty 70.3 0.0 82.6 0.0 78.6 0.0 72.4 0.0 76.8 0.0 76.5 0.0 Average 70.3 81.5 76.7 69.6 74.7 74.2 Standard deviation 1.2 1.9 1.5 2.1 2.9 2.0 Back Suspension / Chassis Mounts X Y Z Trim configuration Actual Delta Actual Delta Actual Delta IP Fs Rs Parcel Carpets 65.7 6.1 60.0 12.6 64.3 10.5 IP Rs Parcel Carpets 68.2 3.5 65.4 7.1 67.5 7.2 IP Rs Parcel 68.7 3.0 65.5 7.1 66.9 7.8 Rs Parcel 69.9 1.8 61.6 11.0 67.3 7.4 Rear seats 70.2 1.5 67.0 5.6 68.8 6.0 Empty 71.7 0.0 72.6 0.0 74.8 0.0 Average 69.1 65.3 68.3 Standard deviation 2.1 4.4 3.5 35 C H A L M E R S,M aster’s T hesis 2007:149 3.3.6. NTF and VTF Influence of Carpet Trim at Driver’s Outer Ear and Windscreen from Excitation Point 102 Z-Direction. In this section, the influence of the carpet trim on a single NTF and VTF measurement point excited at cap fixture 102 z-direction is investigated. For easy viewing, the measurement results for NTF and VTF are represented in two plots: range of 20Hz to 300Hz and range of 300Hz to 600Hz. Figure 3.35 shows the NTF comparison results measured at the driver’s outer ear. The car- pets are observed to be effective sound absorbers as the discrepancies between the two trim configurations start to increase from around 170Hz onwards. (a) NTF from 20Hz to 300Hz. (b) NTF from 300Hz to 600Hz. Figure 3.35.: NTF investigation on the carpets influence measured the driver’s outer ear position and excited at cap fixture 102 z-direction. As for VTF, the comparison results are plotted based on the measurement at the vehicle wind- screen as shown in figure 3.36. Contrary to NTF, the VTF comparison results at the windscreen yield no significant difference. This phenomena indicates that the mass of the carpets is probably not sufficient enough to inhibit the vibration substantially or simply, the vibration is transmit- ted through another path in the vehicle (bypassing the carpets) from the excitation point to the windscreen. CHALMERS, Master’s Thesis 2007:149 36 (a) VTF from 20Hz to 300Hz. (b) VTF from 300Hz to 600Hz. Figure 3.36.: VTF investigation on the carpets influence measured at the windscreen and excited at cap fixture 102 z-direction. 3.3.7. NTF and VTF Influence of IP Trim at Driver’s Outer Ear and Windscreen from Excitation Point 102 Z-Direction. The influence of the heaviest trim in the experiment (the IP) is investigated. The excitation position and measurement point for NTF and VTF are the same as the previous section (section 3.3.6). Relative to the carpet trim, the IP trim already produces a higher influence in terms of damping on the NTF from 50Hz onwards and the discrepancies increase with frequency (as shown in figure 3.37). (a) NTF from 20Hz to 300Hz. (b) NTF from 300Hz to 600Hz. Figure 3.37.: NTF investigation on the IP influence measured at the driver’s outer ear and excited at cap fixture 102 z-direction. 37 CHALMERS, Master’s Thesis 2007:149 As for the VTF results measured at the windscreen, some levels of damping can also be observed in figure 3.37 along the frequency range. The mass and the mounting position of the IP trim have inhibited the vibration excited at cap fixture 102 (although not truly significant). (a) VTF from 20Hz to 300Hz. (b) VTF from 300Hz to 600Hz. Figure 3.38.: VTF investigation on the IP influence measured at the windscreen and excited at cap fixture 102 z-direction. CHALMERS, Master’s Thesis 2007:149 38 4. Conclusion Based on the measurement results and discussion, the trim parts that significantly influence the acoustical behavior in the vehicle cavity are the rear seats and the IP. Mounting these trim parts basically changes or shifts the acoustical modes as well as inducing additional damping and mass to the vehicle test structure (BIB). When the rear seats and the parcel shelf trims are mounted, decoupling of the passenger cabin from the trunk occurs and the acoustic field responds with a shifting of the longitudinal modes due to the shorter length of the vehicle cavity. Introducing the IP inside the vehicle cavity yields some interesting effects. A decrease in fre- quency of the first longitudinal mode is observed, which is initially suspected due to the air cavity below the IP. However, sealing the air cavity below the IP with damping layers and min- eral wool does not show any noticeable changes. The second hypothesis explains the effect by treating the wall of the vehicle cavity as a mass-spring system. Adding the IP is analogous to introducing additional mass (which is significant) and reducing stiffness (softer surface of the IP) to the system which subsequently lower the longitudinal modes based on the system charac- teristic. At the driver’s outer ear standpoint, the sound pressure level of the carpets show a smoother and damped characteristic throughout the frequency range, whereas the front seats demonstrate a significant dip at frequency (around 350Hz) and only show more damping characteristic from 900Hz onwards. The IP again dominantly influence the acoustic field in the vehicle cavity re- gardless which combination of other trim parts, and could potentially decreases the overall sound pressure 4.5dBA to 8.6dBa. Finally, it is observed that the rear seats and rs parcel trim configu- ration show an increment of the sound pressure level at certain frequency range. The investigation of the 40Hz peak shows that main structural influence to the acoustic modes in the vehicle cavity comes from the rear window vibration. For both cases of A-MTF and A-FRF the level of the 40Hz peak was significantly decreased when the rear window was mass-loaded. The sound field in the vehicle cavity and vehicle structure are mutually affecting each other where there are resemblance between the A-MTF curves of the rear window (vibration) and the A-FRF of the longitudinal modes. This indicates that the rear window structure is relatively sensitive to the longitudinal acoustic modes. The data from the NTF and VTF were averaged into excitation mount groups to ease analy- 39 sis. Based on the results, a systematic trend can be observed where more trim parts generally contribute to more damping to the measurement response. At the driver’s outer ear standpoint, the noise is easily transmitted to the passenger cabin from the engine mounts in comparison with front suspension and back suspension chassis mounts. The IP and the rear seats dominantly influences the behavior of the measurement response. All the data/measurement boils down to the usefulness of aiding and validating the company’s CAE vehicle model as well as highlighting trends or behaviors that are never noticed before (or taken lightly). Trim items like rear seats, IP and parcel shelf and their combinations should be taken in account in future modeling specially for frequencies below 250 Hz. Figure 4.1 is illustrated to show a subjective guideline of the influence of each individual trim items in the respective frequency range. The guideline will also serve as a form of priority call before the CAE modeling. Figure 4.1.: Vehicle trim parts influence according to frequency. CHALMERS, Master’s Thesis 2007:149 40 5. Future Work Several investigation and experiment can be performed as a future resort. The interesting phe- nomena of the IP trim (frequency decrement at the longitudinal mode) can still be further inves- tigated by constructing a wooden or steel IP without the air cavity below. On the other hand, the sealing of the air cavity below the IP can be improved by using proper and heavier materials for more effective sealing. This master thesis was designed primarily to aid and validate the CAE vehicle model due to the project’s nature of having extensive measurement activities. A comparison of the measure- ment and CAE results will be beneficial in further understanding and enhancing the future CAE vehicle model. Lastly, measurement on more than one vehicle for data collection in future may allow a rel- atively more effective data comparison, validation as well as commonality study. Besides, a wider or refined range of trim configurations can also be selected in future. 41 CHALMERS, Master’s Thesis 2007:149 42 References Ewins, D.J.: Modal Testing: Theory, Practice and Application, Second Edition, Research Stud- ies Press LTD, England, ISBN 0 86380 218 4, 2000 David, L. and Blong, X.: Experimental Study into the Influence of Interior Trim on the Noise Transfer Functions, Thesis work, Department of Applied Acoustics, Chalmers University of Technology, Göteborg, 2005 Miguel, C.: Influence of Bolted Items on the Results and Consistency of Modal Analysis, Thesis work, Department of Applied Acoustics, Chalmers University of Technology, Göteborg, 2007 Andrzej, P. and Tage, B.: An Investigation of the Coupling Between the Passenger Compart- ment and the Trunk in the Sedan, SAE International Paper, No 2007-01-2356, 2007 Kropp, W.: Active Noise Control, Lecture notes, Department of Applied Acoustics, Chalmers University of Technology, Göteborg, 2005 Yang, Q. and Jeff, V.: Acoustic Modeling and Optimization of Seat for Boom Noise, SAE International Paper, No 971950, 1997 Michael, A. and Taner, O.: CAE Interior Cavity Model Validation using Acoustic Modal Anal- ysis, SAE International Paper, No 2007-01-2167, 2007 Shinichi, M. ,Akihiko, H. and Yoshihiko, H.: Interior Noise Analysis Based on Acoustic Exci- tation Tests at Low-Frequency Range, SAE International Paper, No 1999-01-1806, 1999 Alexis, S. and Francois, V.: Numerical Prediction of a Whole Car Vibro-Acoustic Behavior at Low Frequencies, SAE International Paper, No 2001-01-1521, 2001 Gregor, K.: Panel Noise Contribution Analysis: An Experimental Method for Determining the Noise Contributions of Panels to an Interior Noise, SAE International Paper, No 2003-01-1410, 2003 Mansinh, K., Sajith, E., Amit, C.: Investigation of Factors Influencing Vehicle Audio Speaker Locations for Better Sound Quality and Spread, SAE International Paper, No 2007-01-2318, 2007 43 Ola, H. and Per, K.: The Construction and Placement of a Microphone Array for Automo- tive Use, Thesis work, Department of Applied Acoustics, Chalmers University of Technology, Göteborg, 1991 Andreas, G. and Per, U.: Reciprocal Measurement of Mechano-Acoustical Transfer Functions in Vehicles, Thesis work, Department of Applied Acoustics, Chalmers University of Technol- ogy, Göteborg, 1995 Jin, K.L. and Jang, M.L.: Forced Vibro-Acoustical Analysis for a Theoretical Model of a Passenger Compartment with a Trunk - Part I and II, ScienceDirect, Journal of Sound and Vibration No 299 (2007) 900-917, 2007 J.W.Lee, J.M.Lee and S.H.Kim: Acoustical Analysis of Multiple Cavities Connected by Necks in Series with a Consideration of Evanescent Waves, ScienceDirect, Journal of Sound and Vibration No 273 (2004) 515-542, 2004 CHALMERS, Master’s Thesis 2007:149 44 A. Measurement Setup Pictures and Plots A.1. Vehicle Trim Parts Description Front Seats Left and right front seats (including the head rest) were only used, each mounted with four screws during measurement. The textures of the front seats were made of fabric. Rear Seats Rear seats (including the back rest) were only used. The bottom seat was mounted by clips and the back rest was mounted by two screws at each sides. The textures of the rear seats were made of fabric (can be seen in figure A.4). No damping layer was placed under the bottom seat during measurement. The damping layer was regarded as part of the carpets trim configuration. Carpets Four pieces of carpets (front right, front left, middle and back) were used as shown in figure A.1. The back piece was actually the damping layer beneath the rear seats. No glue or any form of adhesives were used to mount the carpets during measurement. Figure A.1.: Trim carpets arrangement in the vehicle. 45 IP The IP (as shown in figure A.2) was mounted by screws only on the BIB during measurement. No additional parts were used and the IP was mounted as-is. Metal plates on the BIB (as shown in figure A.3) were removed prior to the IP mounting. (a) IP front view. (b) IP back view. Figure A.2.: Trim IP used in the measurement. Figure A.3.: Metal plates removed to mount the IP. CHALMERS, Master’s Thesis 2007:149 46 Parcel shelf The parcel shelf trims included the two side pillar trims, the parcel shelf cover and a damping layer beneath. The holes from the side pillar trims were covered by mineral wools. No adhesives were used and the parcel shelf configuration was mounted as-is during the measurement (as shown in figure A.4). Kindly ignore the rear seats from the figure as the rear seats was only used later in other trim combinations. Figure A.4.: Parcel shelf trim (without the seat) mounted in the vehicle. Trim combinations Measurement for other trim combinations were performed with all the trims described previously only. NO additional trims were used other than the mentioned. Only the SAME trim parts were repeatedly used. 47 CHALMERS, Master’s Thesis 2007:149 A.2. Acoustical Excitation and Measurement Positions A.2.1. Loudspeaker Dimension and Position Co-ordinates (a) Top view of loudspeaker position in the vehicle cavity. (b) Side view of loudspeaker position in the vehicle cavity. Figure A.5.: Loudspeaker position in the vehicle cavity. Figure A.6.: LSP dimensions CHALMERS, Master’s Thesis 2007:149 48 A.2.2. Microphones Positions (a) Microphone 1 position. (b) Microphone 12 position. Figure A.7.: Microphones 1 and 12 positions. (a) Microphones 13 to 20 position. (b) Microphones 21 to 36 position. Figure A.8.: Microphones 13 to 36 positions. 49 CHALMERS, Master’s Thesis 2007:149 (a) Microphones 37 to 42 position. (b) Microphones 43 to 54 position. Figure A.9.: Microphones 37 to 54 positions. (a) Microphones 55 to 60 position. (b) Microphone 61 position. Figure A.10.: Microphones 55 to 61 positions. CHALMERS, Master’s Thesis 2007:149 50 A.2.3. Accelerometers Positions (a) Accelerometer position on the roof. (b) Accelerometer position on the parcel. Figure A.11.: Accelerometers positions on the roof and the parcel shelf. Figure A.12.: Accelerometer position on the rear window 51 CHALMERS, Master’s Thesis 2007:149 A.2.4. A-FRF Plots (a) Lateral Fs mode for Empty configuration. (b) Lateral FS mode for Carpets configuration. Figure A.13.: Lateral Fs mode for Empty and Carpets configuration. (a) Lateral Fs mode for Front Seats configuration. (b) Lateral Fs mode for Rear Seats configuration. Figure A.14.: Lateral Fs mode for Front and Rear Seats configurations. CHALMERS, Master’s Thesis 2007:149 52 (a) Lateral Fs mode for Rear Seats Parcel configuration. (b) Lateral Fs mode for Front Seats Rear Seats Parcel con- figuration. Figure A.15.: Lateral Fs mode for Rear Seats Parcel and Front Seats Rear Seats Parcel configurations. (a) Lateral Fs mode for Front Seats Rear Seats Carpets Par- cel configuration. (b) Lateral Fs mode for IP configuration. Figure A.16.: Lateral Fs mode for Front Seats Rear Seats Carpets Parcel and IP configurations. 53 CHALMERS, Master’s Thesis 2007:149 (a) Lateral Fs mode for IP Front Seats configuration. (b) Lateral Fs mode for IP Carpets configuration. Figure A.17.: Lateral Fs mode for IP Front Seats and IP Carpets configurations. (a) Lateral Fs mode for IP Rear Seats configuration. (b) Lateral Fs mode for IP Rear Seats Parcel configuration. Figure A.18.: Lateral Fs mode for IP Rear Seats and IP Rear Seats Parcel configurations. CHALMERS, Master’s Thesis 2007:149 54 (a) Lateral Fs mode for IP Front Seats Rear Seats Parcel configuration. (b) Lateral Fs mode for IP Front Seats Rear Seats Carpets Parcel configuration. Figure A.19.: Lateral Fs mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. (a) Lateral Parcel mode for Empty configuration. (b) Lateral Parcel mode for Carpets configuration. Figure A.20.: Lateral Parcel mode for Empty and Carpets configuration. 55 CHALMERS, Master’s Thesis 2007:149 (a) Lateral Parcel mode for Front Seats configuration. (b) Lateral Parcel mode for Rear Seats configuration. Figure A.21.: Lateral Parcel mode for Front and Rear Seats configurations. (a) Lateral Parcel mode for Rear Seats Parcel configuration. (b) Lateral Parcel mode for Front Seats Rear Seats Parcel configuration. Figure A.22.: Lateral Parcel mode for Rear Seats Parcel and Front Seats Rear Seats Parcel configurations. CHALMERS, Master’s Thesis 2007:149 56 (a) Lateral Parcel mode for Front Seats Rear Seats Carpets Parcel configuration. (b) Lateral Parcel mode for IP configuration. Figure A.23.: Lateral Parcel mode for Front Seats Rear Seats Carpets Parcel and IP configurations. (a) Lateral Parcel mode for IP Front Seats configuration. (b) Lateral Parcel mode for IP Carpets configuration. Figure A.24.: Lateral Parcel mode for IP Front Seats and IP Carpets configurations. 57 CHALMERS, Master’s Thesis 2007:149 (a) Lateral Parcel mode for IP Rear Seats configuration. (b) Lateral Parcel mode for IP Rear Seats Parcel configura- tion. Figure A.25.: Lateral Parcel mode for IP Rear Seats and IP Rear Seats Parcel configurations. (a) Lateral Parcel mode for IP Front Seats Rear Seats Parcel configuration. (b) Lateral Parcel mode for IP Front Seats Rear Seats Car- pets Parcel configuration. Figure A.26.: Lateral Parcel mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. CHALMERS, Master’s Thesis 2007:149 58 (a) Lateral Rs mode for Empty configuration. (b) Lateral Rs mode for Carpets configuration. Figure A.27.: Lateral Rs mode for Empty and Carpets configuration. (a) Lateral Rs mode for Front Seats configuration. (b) Lateral Rs mode for Rear Seats configuration. Figure A.28.: Lateral Rs mode for Front and Rear Seats configurations. 59 CHALMERS, Master’s Thesis 2007:149 (a) Lateral Rs mode for Rear Seats Parcel configuration. (b) Lateral Rs mode for Front Seats Rear Seats Parcel con- figuration. Figure A.29.: Lateral Rs mode for Rear Seats Parcel and Front Seats Rear Seats Parcel configurations. (a) Lateral Rs mode for Front Seats Rear Seats Carpets Par- cel configuration. (b) Lateral Rs mode for IP configuration. Figure A.30.: Lateral Rs mode for Front Seats Rear Seats Carpets Parcel and IP configurations. CHALMERS, Master’s Thesis 2007:149 60 (a) Lateral Rs mode for IP Front Seats configuration. (b) Lateral Rs mode for IP Carpets configuration. Figure A.31.: Lateral Rs mode for IP Front Seats and IP Carpets configurations. (a) Lateral Rs mode for IP Rear Seats configuration. (b) Lateral Rs mode for IP Rear Seats Parcel configuration. Figure A.32.: Lateral Rs mode for IP Rear Seats and IP Rear Seats Parcel configurations. 61 CHALMERS, Master’s Thesis 2007:149 (a) Lateral Rs mode for IP Front Seats Rear Seats Parcel configuration. (b) Lateral Rs mode for IP Front Seats Rear Seats Carpets Parcel configuration. Figure A.33.: Lateral Rs mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. (a) Vertical mode for Empty configuration. (b) Vertical mode for Carpets configuration. Figure A.34.: Vertical mode for Empty and Carpets configuration. CHALMERS, Master’s Thesis 2007:149 62 (a) Vertical mode for Front Seats configuration. (b) Vertical mode for Rear Seats configuration. Figure A.35.: Vertical mode for Front and Rear Seats configurations. (a) Vertical mode for Rear Seats Parcel configuration. (b) Vertical mode for Front Seats Rear Seats Parcel config- uration. Figure A.36.: Vertical mode for Rear Seats Parcel and Front Seats Rear Seats Parcel configurations. 63 CHALMERS, Master’s Thesis 2007:149 (a) Vertical mode for Front Seats Rear Seats Carpets Parcel configuration. (b) Vertical mode for IP configuration. Figure A.37.: Vertical mode for Front Seats Rear Seats Carpets Parcel and IP configurations. (a) Vertical mode for IP Front Seats configuration. (b) Vertical mode for IP Carpets configuration. Figure A.38.: Vertical mode for IP Front Seats and IP Carpets configurations. CHALMERS, Master’s Thesis 2007:149 64 (a) Vertical mode for IP Rear Seats configuration. (b) Vertical mode for IP Rear Seats Parcel configuration. Figure A.39.: Vertical mode for IP Rear Seats and IP Rear Seats Parcel configurations. (a) Vertical mode for IP Front Seats Rear Seats Parcel con- figuration. (b) Vertical mode for IP Front Seats Rear Seats Carpets Par- cel configuration. Figure A.40.: Vertical mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. 65 CHALMERS, Master’s Thesis 2007:149 (a) Trunk Lateral mode for Empty configuration. (b) Trunk Lateral mode for Carpets configuration. Figure A.41.: Trunk Lateral mode for Empty and Carpets configuration. (a) Trunk Lateral mode for Front Seats configuration. (b) Trunk Latreal mode for Rear Seats configuration. Figure A.42.: Trunk Lateral mode for Front and Rear Seats configurations. CHALMERS, Master’s Thesis 2007:149 66 (a) Trunk Lateral mode for Rear Seats Parcel configuration. (b) Trunk Lateral mode for Front Seats Rear Seats Parcel configuration. Figure A.43.: Trunk Lateral mode for Rear Seats Parcel and Front Seats Rear Seats Parcel configurations. (a) Trunk Lateral mode for Front Seats Rear Seats Carpets Parcel configuration. (b) Trunk Lateral mode for IP configuration. Figure A.44.: Trunk Lateral mode for Front Seats Rear Seats Carpets Parcel and IP configurations. 67 CHALMERS, Master’s Thesis 2007:149 (a) Trunk Lateral mode for IP Front Seats configuration. (b) Trunk Lateral mode for IP Carpets configuration. Figure A.45.: Trunk Lateral mode for IP Front Seats and IP Carpets configurations. (a) Trunk Lateral mode for IP Rear Seats configuration. (b) Trunk Lateral mode for IP Rear Seats Parcel configura- tion. Figure A.46.: Trunk lateral mode for IP Rear Seats and IP Rear Seats Parcel configurations. CHALMERS, Master’s Thesis 2007:149 68 (a) Trunk Lateral mode for IP Front Seats Rear Seats Parcel configuration. (b) Trunk Lateral mode for IP Front Seats Rear Seats Car- pets Parcel configuration. Figure A.47.: Trunk Lateral mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. (a) Trunk Vertical mode for Empty configuration. (b) Trunk Vertical mode for Carpets configuration. Figure A.48.: Trunk Vertical mode for Empty and Carpets configuration. 69 CHALMERS, Master’s Thesis 2007:149 (a) Trunk Vertical mode for Front Seats configuration. (b) Trunk Vertical mode for Rear Seats configuration. Figure A.49.: Trunk Vertical mode for Front and Rear Seats configurations. (a) Trunk Vertical mode for Rear Seats Parcel configuration. (b) Trunk Vertical mode for Front Seats Rear Seats Parcel configuration. Figure A.50.: Trunk Vertical mode for Rear Seats Parcel and Front Seats Rear Seats Parcel configura- tions. CHALMERS, Master’s Thesis 2007:149 70 (a) Trunk Vertical mode for Front Seats Rear Seats Carpets Parcel configuration. (b) Trunk Vertical mode for IP configuration. Figure A.51.: Trunk Vertical mode for Front Seats Rear Seats Carpets Parcel and IP configurations. (a) Trunk Vertical mode for IP Front Seats configuration. (b) Trunk Vertical mode for IP Carpets configuration. Figure A.52.: Trunk Vertical mode for IP Front Seats and IP Carpets configurations. 71 CHALMERS, Master’s Thesis 2007:149 (a) Trunk Vertical mode for IP Rear Seats configuration. (b) Trunk Vertical mode for IP Rear Seats Parcel configura- tion. Figure A.53.: Trunk Vertical mode for IP Rear Seats and IP Rear Seats Parcel configurations. (a) Trunk Vertical mode for IP Front Seats Rear Seats Parcel configuration. (b) Trunk Vertical mode for IP Front Seats Rear Seats Car- pets Parcel configuration. Figure A.54.: Trunk Vertical mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. CHALMERS, Master’s Thesis 2007:149 72 (a) Trunk Longitudinal mode for Empty configuration. (b) Trunk Longitudinal mode for Carpets configuration. Figure A.55.: Trunk Lonitudinal mode for Empty and Carpets configuration. (a) Trunk Longitudinal mode for Front Seats configuration. (b) Trunk Longitudinal mode for Rear Seats configuration. Figure A.56.: Trunk Longitudinal mode for Front and Rear Seats configurations. 73 CHALMERS, Master’s Thesis 2007:149 (a) Trunk Longitudinal mode for Rear Seats Parcel config- uration. (b) Trunk Longitudinal mode for Front Seats Rear Seats Parcel configuration. Figure A.57.: Trunk Longitudinal mode for Rear Seats Parcel and Front Seats Rear Seats Parcel config- urations. (a) Trunk Longitudinal mode for Front Seats Rear Seats Carpets Parcel configuration. (b) Trunk Longitudinal mode for IP configuration. Figure A.58.: Trunk Longitudinal mode for Front Seats Rear Seats Carpets Parcel and IP configurations. CHALMERS, Master’s Thesis 2007:149 74 (a) Trunk Longitudinal mode for IP Front Seats configura- tion. (b) Trunk Longitudinal mode for IP Carpets configuration. Figure A.59.: Trunk Longitudinal mode for IP Front Seats and IP Carpets configurations. (a) Trunk Longitudinal mode for IP Rear Seats configura- tion. (b) Trunk Longitudinal mode for IP Rear Seats Parcel con- figuration. Figure A.60.: Trunk Longitudinal mode for IP Rear Seats and IP Rear Seats Parcel configurations. 75 CHALMERS, Master’s Thesis 2007:149 (a) Trunk Longitudinal mode for IP Front Seats Rear Seats Parcel configuration. (b) Trunk Longitudinal mode for IP Front Seats Rear Seats Carpets Parcel configuration. Figure A.61.: Trunk Longitudinal mode for IP Front Seats Rear Seats Parcel and IP Front Seats Rear Seats Carpets Parcel configurations. CHALMERS, Master’s Thesis 2007:149 76 A.2.5. A-MTF Plots (a) Roof vibration for Empty configuration. (b) Roof vibration for Carpets configuration. Figure A.62.: Roof vibration for Empty and Carpets configurations. (a) Roof vibration for Rear seats configuration. (b) Roof vibration for Front seats configuration. Figure A.63.: Roof vibration for Rear seats and Front seats configurations. 77 CHALMERS, Master’s Thesis 2007:149 (a) Roof vibration for Rear seats Parcel configuration. (b) Roof vibration for Front seats Rear seats and Parcel con- figuration. Figure A.64.: Roof vibration for Rear seats Parcel and Front seats Rear seats Parcel configurations. (a) Roof vibration for Front seats Rear seats Carpets Parcel configuration. (b) Roof vibration for IP configuration. Figure A.65.: Roof vibration for Front seats Rear seats Carpets Parcel and IP configurations. CHALMERS, Master’s Thesis 2007:149 78 (a) Roof vibration for IP Rear seats configuration. (b) Roof vibration for IP Front seats configuration. Figure A.66.: Roof vibration for IP Rear seats and IP Front seats configurations. (a) Roof vibration for IP Carpets configuration. (b) Roof vibration for IP Rear seats Parcel configuration. Figure A.67.: Roof vibration for IP Carpets and IP Rear seats Parcel configurations. 79 CHALMERS, Master’s Thesis 2007:149 (a) Roof vibration for IP Front seats Rear seats Parcel con- figuration. (b) Roof vibration for IP Front seats Rear seats Carpets Par- cel configuration. Figure A.68.: Roof vibration for IP Front seats Rear seats Parcel and IP Front seats Rear seats Carpets Parcel configurations. (a) Rear window vibration for Empty configuration. (b) Rear window vibration for Carpets configuration. Figure A.69.: Rear window vibration for Empty and Carpets configurations. CHALMERS, Master’s Thesis 2007:149 80 (a) Rear window vibration for Rear seats configuration. (b) Rear window vibration for Front seats configuration. Figure A.70.: Rear window vibration for Rear seats and Front seats configurations. (a) Rear window vibration for Rear seats Parcel configura- tion. (b) Rear window vibration for Front seats Rear seats and Parcel configuration. Figure A.71.: Rear window vibration for Rear seats Parcel and Front seats Rear seats Parcel configura- tions. 81 CHALMERS, Master’s Thesis 2007:149 (a) Rear window vibration for Front seats Rear seats Car- pets Parcel configuration. (b) Rear window vibration for IP configuration. Figure A.72.: Rear window vibration for Front seats Rear seats Carpets Parcel and IP configurations. (a) Rear window vibration for IP Rear seats configuration. (b) Rear window vibration for IP Front seats configuration. Figure A.73.: Rear window vibration for IP Rear seats and IP Front seats configurations. CHALMERS, Master’s Thesis 2007:149 82 (a) Rear window vibration for IP Carpets configuration. (b) Rear window vibration for IP Rear seats Parcel configu- ration. Figure A.74.: Rear window vibration for IP Carpets and IP Rear seats Parcel configurations. (a) Rear window vibration for IP Front seats Rear seats Par- cel configuration. (b) Rear window vibration for IP Front seats Rear seats Car- pets Parcel configuration. Figure A.75.: Rear window vibration for IP Front seats Rear seats Parcel and IP Front seats Rear seats Carpets Parcel configurations. 83 CHALMERS, Master’s Thesis 2007:149 (a) Parcel vibration for Empty configuration. (b) Parcel vibration for Carpets configuration. Figure A.76.: Parcel vibration for Empty and Carpets configurations. (a) Parcel vibration for Rear seats configuration. (b) Parcel vibration for Front seats configuration. Figure A.77.: Parcel vibration for Rear seats and Front seats configurations. CHALMERS, Master’s Thesis 2007:149 84 (a) Parcel vibration for Rear seats Parcel configuration. (b) Parcel vibration for Front seats Rear seats and Parcel configuration. Figure A.78.: Parcel vibration for Rear seats Parcel and Front seats Rear seats Parcel configurations. (a) Parcel vibration for Front seats Rear seats Carpets Parcel configuration. (b) Parcel vibration for IP configuration. Figure A.79.: Parcel vibration for Front seats Rear seats Carpets Parcel and IP configurations. 85 CHALMERS, Master’s Thesis 2007:149 (a) Parcel vibration for IP Rear seats configuration. (b) Parcel vibration for IP Front seats configuration. Figure A.80.: Parcel vibration for IP Rear seats and IP Front seats configurations. (a) Parcel vibration for IP Carpets configuration. (b) Parcel vibration for IP Rear seats Parcel configuration. Figure A.81.: Parcel vibration for IP Carpets and IP Rear seats Parcel configurations. CHALMERS, Master’s Thesis 2007:149 86 (a) Parcel vibration for IP Front seats Rear seats Parcel con- figuration. (b) Parcel vibration for IP Front seats Rear seats Carpets Parcel configuration. Figure A.82.: Parcel vibration for IP Front seats Rear seats Parcel and IP Front seats Rear seats Carpets Parcel configurations. 87 CHALMERS, Master’s Thesis 2007:149 A.2.6. Mass-load investigation Plots (a) Mass loading effect on Parcel vibration response. (b) Mass loading effect on Rear window vibration response. Figure A.83.: Parcel vibration for IP Front seats Rear seats Parcel and IP Front seats Rear seats Carpets Parcel configurations. Figure A.84.: Mass loading effect on mic 1 CHALMERS, Master’s Thesis 2007:149 88 A.3. Mechanical Excitation and Measurement Positions A.3.1. Excitation Positions and Directions (a) Cap fixtures for body 241, 205 and 902. (b) Cap fixtures for body 901 and 141. Figure A.85.: BIB front top cap fixtures location and mechanical excitation directions. (a) Cap fixtures for body 201 and 202. (b) Cap fixtures for body 101 and 102. Figure A.86.: BIB front bottom cap fixtures location and mechanical excitation directions. 89 CHALMERS, Master’s Thesis 2007:149 (a) Cap fixtures for body 301, 302, 321 and 341. (b) Cap fixtures for body 401, 402, 421 and 441. Figure A.87.: BIB back bottom cap fixtures location and mechanical excitation directions. CHALMERS, Master’s Thesis 2007:149 90 A.3.2. Measuremant Positions (a) Measurement points 001 and 003. (b) Measurement point 002. Figure A.88.: BIB NTF measurement positions. (a) Measurement point 004. (b) Measurement point 006. Figure A.89.: BIB NTF measurement positions. 91 CHALMERS, Master’s Thesis 2007:149 (a) Measurement points 005 and 641. (b) Measurement point 012. Figure A.90.: BIB NTF measurement positions. (a) Measurement point 112. (b) Measurement point 606. Figure A.91.: BIB NTF measurement positions. CHALMERS, Master’s Thesis 2007:149 92 (a) Measurement point 616. (b) Measurement point 627. Figure A.92.: BIB NTF measurement positions. (a) Measurement point 635. (b) Measurement point 638. Figure A.93.: BIB NTF measurement positions. 93 CHALMERS, Master’s Thesis 2007:149 A.3.3. NTF Plots Figure A.94.: Driver outer ear 0-300 Hz Figure A.95.: Driver outer ear 300-600 Hz CHALMERS, Master’s Thesis 2007:149 94 Figure A.96.: Passenger outer ear 0-300 Hz Figure A.97.: Passenger outer ear 300-600 Hz 95 CHALMERS, Master’s Thesis 2007:149 Figure A.98.: Pedals 0-300 Hz Figure A.99.: Pedals 300-600 Hz CHALMERS, Master’s Thesis 2007:149 96 Figure A.100.: Rear passenger outer ear 0-300 Hz Figure A.101.: Rear passenger outer ear 300-600 Hz 97 CHALMERS, Master’s Thesis 2007:149 Figure A.102.: Parcel shelf 0-300 Hz Figure A.103.: Parcel shelf 300-600 Hz On figure A.102 and figure A.103 the results for the parcel shelf are presented. CHALMERS, Master’s Thesis 2007:149 98 Figure A.104.: Trunk 0-300 Hz Figure A.105.: Trunk 300-600 Hz On figure A.104 and figure A.105 the results for the trunk are presented. 99 CHALMERS, Master’s Thesis 2007:149 A.3.4. VTF Plots Figure A.106.: Driver seat left mount 0-300 Hz Figure A.107.: Driver seat left mount 300-600 Hz On figure A.106 and figure A.107 the results for the driver seat left mount are presented. CHALMERS, Master’s Thesis 2007:149 100 Figure A.108.: Front bumper 0-300 Hz Figure A.109.: Front bumper 300-600 Hz On figure A.108 and figure A.109 the results for the front bumper are presented. 101 CHALMERS, Master’s Thesis 2007:149 Figure A.110.: Windscreen 0-300 Hz Figure A.111.: Windscreen 300-600 Hz CHALMERS, Master’s Thesis 2007:149 102 Figure A.112.: Roof 0-300 Hz Figure A.113.: Roof 300-600 Hz 103 CHALMERS, Master’s Thesis 2007:149 Figure A.114.: Rear window 0-300 Hz Figure A.115.: Rear window 300-600 Hz CHALMERS, Master’s Thesis 2007:149 104 Figure A.116.: Front floor rear 0-300 Hz Figure A.117.: Front floor rear 300-600 Hz 105 CHALMERS, Master’s Thesis 2007:149 Figure A.118.: Rear floor front 0-300 Hz Figure A.119.: Rear floor front 300-600 Hz CHALMERS, Master’s Thesis 2007:149 106 Figure A.120.: Parcel shelf 0-300 Hz Figure A.121.: Parcel shelf 300-600 Hz 107 CHALMERS, Master’s Thesis 2007:149 Figure A.122.: Point mobility 0-300 Hz Figure A.123.: Point mobility 300-600 Hz CHALMERS, Master’s Thesis 2007:149 108 B. Matlab GUI and Code B.1. Acoustical Excitation Matlab Code B.1.1. A-FRF Matlab Code Figure B.1.: GUI matlab program to analyze A-FRF measurements. 109 1: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 2: % CAR_INTERIOR_ALL_VER4 M-file for car_interior_all_ver4.fig - Created by 3: % Teik Huat Ong & Branislav Ivanov 2007 4: % A matlab graphical interface program to analyze all the a-frf responses. 5: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 6: 7: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 8: % Function to initialize the graphical handlers and state. 9: function varargout = car_interior_all_ver4(varargin) 10: % Begin initialization code 11: gui_Singleton = 1; 12: gui_State = struct(’gui_Name’, mfilename, ... 13: ’gui_Singleton’, gui_Singleton, ... 14: ’gui_OpeningFcn’, @car_interior_all_ver4_OpeningFcn, ... 15: ’gui_OutputFcn’, @car_interior_all_ver4_OutputFcn, ... 16: ’gui_LayoutFcn’, [] , ... 17: ’gui_Callback’, []); 18: if nargin && ischar(varargin{1}) 19: gui_State.gui_Callback = str2func(varargin{1}); 20: end 21: 22: if nargout 23: [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:}); 24: else 25: gui_mainfcn(gui_State, varargin{:}); 26: end 27: % End initialization code 28: 29: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 30: % Function to plot all the measurement arrays for Empty Trim Configuration 31: % while the figure is opening. 32: function car_interior_all_ver4_OpeningFcn(hObject, eventdata, handles, varargin) 33: 34: handles.output = hObject; 35: guidata(hObject, handles); 36: 37: load .\frequency.mat; 38: %Longitudinal 39: axes(handles.axes1); 40: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_longitudinal_parcel’; 41: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 42: hold on; 43: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_longitudinal’; 44: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 45: xlim ([20 300]); 46: ylim ([-1.5 1.5]); 47: 48: %Lateral Fs 49: axes(handles.axes2); CHALMERS, Master’s Thesis 2007:149 110 50: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_lateral_fs’; 51: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 52: hold on; 53: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 54: xlim ([20 300]); 55: ylim ([-1.5 1.5]); 56: 57: %Lateral Rs 58: axes(handles.axes3); 59: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_lateral_rs’; 60: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 61: hold on; 62: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 63: xlim ([20 300]); 64: ylim ([-1.5 1.5]); 65: 66: %Lateral Parcel 67: axes(handles.axes4); 68: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_lateral_parcel’; 69: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 70: hold on; 71: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 72: xlim ([20 300]); 73: ylim ([-1.5 1.5]); 74: 75: %Vertical 76: axes(handles.axes5); 77: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_vertical’; 78: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 79: hold on; 80: plot(fa,imag(Hxy(:,1,7)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 81: xlim ([20 300]); 82: ylim ([-1.5 1.5]); 83: 84: %Longitudinal Trunk 85: axes(handles.axes8); 86: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_trunk_long_lateral’; 87: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 88: hold on; 89: plot(fa,imag(Hxy(:,1,7)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 90: xlim ([20 300]); 91: ylim ([-1.5 1.5]); 92: 93: %Lateral Trunk 94: axes(handles.axes6); 95: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_trunk_long_lateral’; 96: plot(fa,imag(Hxy(:,1,8)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 97: hold on; 98: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 111 CHALMERS, Master’s Thesis 2007:149 99: xlim ([20 300]); 100: ylim ([-1.5 1.5]); 101: 102: %Vertical Trunk 103: axes(handles.axes7); 104: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_trunk_vertical’; 105: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[collar(2) ’-.’]); 106: hold on; 107: plot(fa,imag(Hxy(:,1,6)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 108: xlim ([20 300]); 109: ylim ([-1.5 1.5]); 110: 111: %Pedals 112: axes(handles.axes9); 113: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_pedals’; 114: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),collar(2)); 115: xlim ([20 300]); 116: ylim ([-1.5 1.5]); 117: 118: datacursormode on 119: set(handles.empty_box,’Value’,1); 120: 121: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 122: %Functions to plot according to chosen ’trim configuration’ checkboxes. 123: function empty_box_Callback(hObject, eventdata, handles) 124: if (get(handles.empty_box,’Value’) == get(handles.empty_box,’Max’)) 125: trim_check(’empty’,’b’,handles) 126: else 127: trim_check_remove(’b’,handles) 128: end 129: 130: function fs_box_Callback(hObject, eventdata, handles) 131: if (get(handles.fs_box,’Value’) == get(handles.fs_box,’Max’)) 132: trim_check(’front_seats’,’r’,handles) 133: else 134: trim_check_remove(’r’,handles) 135: end 136: 137: function rs_box_Callback(hObject, eventdata, handles) 138: if (get(handles.rs_box,’Value’) == get(handles.rs_box,’Max’)) 139: trim_check(’rear_seats’,’g’,handles) 140: else 141: trim_check_remove(’g’,handles) 142: end 143: 144: function cpt_box_Callback(hObject, eventdata, handles) 145: if (get(handles.cpt_box,’Value’) == get(handles.cpt_box,’Max’)) 146: trim_check(’carpets’,’k’,handles) 147: else CHALMERS, Master’s Thesis 2007:149 112 148: trim_check_remove(’k’,handles) 149: end 150: 151: function rs_prcl_box_Callback(hObject, eventdata, handles) 152: if (get(handles.rs_prcl_box,’Value’) == get(handles.rs_prcl_box,’Max’)) 153: trim_check(’Rs_parcel’,’m’,handles) 154: else 155: trim_check_remove(’m’,handles) 156: end 157: 158: function fs_rs_prcl_box_Callback(hObject, eventdata, handles) 159: if (get(handles.fs_rs_prcl_box,’Value’) == ... 160: get(handles.fs_rs_prcl_box,’Max’)) 161: trim_check(’Fs_Rs_parcel’,’c’,handles) 162: else 163: trim_check_remove(’c’,handles) 164: end 165: 166: function fs_rs_prcl_cpt_box_Callback(hObject, eventdata, handles) 167: if (get(handles.fs_rs_prcl_cpt_box,’Value’) == ... 168: get(handles.fs_rs_prcl_cpt_box,’Max’)) 169: trim_check(’Fs_Rs_carpets_parcel’,’y’,handles) 170: else 171: trim_check_remove(’y’,handles) 172: end 173: 174: function ip_box_Callback(hObject, eventdata, handles) 175: if (get(handles.ip_box,’Value’) == get(handles.ip_box,’Max’)) 176: trim_check(’ip’,’r’,handles) 177: else 178: trim_check_remove(’r’,handles) 179: end 180: 181: function ip_sealed_box_Callback(hObject, eventdata, handles) 182: if (get(handles.ip_sealed_box,’Value’) == get(handles.ip_sealed_box,’Max’)) 183: trim_check(’ip_sealed’,’k’,handles) 184: else 185: trim_check_remove(’k’,handles) 186: end 187: 188: function ip_fs_box_Callback(hObject, eventdata, handles) 189: if (get(handles.ip_fs_box,’Value’) == get(handles.ip_fs_box,’Max’)) 190: trim_check(’ip_fs’,’b’,handles) 191: else 192: trim_check_remove(’b’,handles) 193: end 194: 195: function ip_rs_box_Callback(hObject, eventdata, handles) 196: if (get(handles.ip_rs_box,’Value’) == get(handles.ip_rs_box,’Max’)) 113 CHALMERS, Master’s Thesis 2007:149 197: trim_check(’ip_rs’,’g’,handles) 198: else 199: trim_check_remove(’g’,handles) 200: end 201: 202: function ip_rs_parcel_box_Callback(hObject, eventdata, handles) 203: if (get(handles.ip_rs_parcel_box,’Value’) == ... 204: get(handles.ip_rs_parcel_box,’Max’)) 205: trim_check(’ip_rs_parcel’,’m’,handles) 206: else 207: trim_check_remove(’m’,handles) 208: end 209: 210: function ip_fs_rs_parcel_box_Callback(hObject, eventdata, handles) 211: if (get(handles.ip_fs_rs_parcel_box,’Value’) == ... 212: get(handles.ip_fs_rs_parcel_box,’Max’)) 213: trim_check(’ip_fs_rs_parcel’,’c’,handles) 214: else 215: trim_check_remove(’c’,handles) 216: end 217: 218: function ip_carpets_box_Callback(hObject, eventdata, handles) 219: if (get(handles.ip_carpets_box,’Value’) == get(handles.ip_carpets_box,’Max’)) 220: trim_check(’ip_carpets’,’k’,handles) 221: else 222: trim_check_remove(’k’,handles) 223: end 224: 225: function ip_fs_rs_carpets_parcel_box_Callback(hObject, eventdata, handles) 226: if (get(handles.ip_fs_rs_carpets_parcel_box,’Value’) == ... 227: get(handles.ip_fs_rs_carpets_parcel_box,’Max’)) 228: trim_check(’ip_fs_rs_carpets_parcel’,’y’,handles) 229: else 230: trim_check_remove(’y’,handles) 231: end 232: 233: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 234: %Function to adjust the x and y axis range of the plot. 235: function bt_range_Callback(hObject, eventdata, handles) 236: fig=handles.figure1; 237: dcm_obj = datacursormode(fig); 238: c_info = getCursorInfo(dcm_obj); 239: load ’.\lsp_data\empty\lsp_ect_mic_meas\c1_empty_longitudinal_parcel’; 240: 241: axes(handles.axes1); 242: axis ([str2double(get(handles.edt_xlower,’String’)) ... 243: str2double(get(handles.edt_xupper,’String’)) ... 244: str2double(get(handles.edt_ylower,’String’)) ... 245: str2double(get(handles.edt_yupper,’String’))]); CHALMERS, Master’s Thesis 2007:149 114 246: axes(handles.axes2); 247: axis ([str2double(get(handles.edt_xlower,’String’)) ... 248: str2double(get(handles.edt_xupper,’String’)) ... 249: str2double(get(handles.edt_ylower,’String’)) ... 250: str2double(get(handles.edt_yupper,’String’))]); 251: axes(handles.axes3); 252: axis ([str2double(get(handles.edt_xlower,’String’)) ... 253: str2double(get(handles.edt_xupper,’String’)) ... 254: str2double(get(handles.edt_ylower,’String’)) ... 255: str2double(get(handles.edt_yupper,’String’))]); 256: axes(handles.axes4); 257: axis ([str2double(get(handles.edt_xlower,’String’)) ... 258: str2double(get(handles.edt_xupper,’String’)) ... 259: str2double(get(handles.edt_ylower,’String’)) ... 260: str2double(get(handles.edt_yupper,’String’))]); 261: axes(handles.axes5); 262: axis ([str2double(get(handles.edt_xlower,’String’)) ... 263: str2double(get(handles.edt_xupper,’String’)) ... 264: str2double(get(handles.edt_ylower,’String’)) ... 265: str2double(get(handles.edt_yupper,’String’))]); 266: axes(handles.axes6); 267: axis ([str2double(get(handles.edt_xlower,’String’)) ... 268: str2double(get(handles.edt_xupper,’String’)) ... 269: str2double(get(handles.edt_ylower,’String’)) ... 270: str2double(get(handles.edt_yupper,’String’))]); 271: axes(handles.axes7); 272: axis ([str2double(get(handles.edt_xlower,’String’)) ... 273: str2double(get(handles.edt_xupper,’String’)) ... 274: str2double(get(handles.edt_ylower,’String’)) ... 275: str2double(get(handles.edt_yupper,’String’))]); 276: axes(handles.axes8); 277: axis ([str2double(get(handles.edt_xlower,’String’)) ... 278: str2double(get(handles.edt_xupper,’String’)) ... 279: str2double(get(handles.edt_ylower,’String’)) ... 280: str2double(get(handles.edt_yupper,’String’))]); 281: axes(handles.axes9); 282: axis ([str2double(get(handles.edt_xlower,’String’)) ... 283: str2double(get(handles.edt_xupper,’String’)) ... 284: str2double(get(handles.edt_ylower,’String’)) ... 285: str2double(get(handles.edt_yupper,’String’))]); 286: 287: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 288: %Function to lauch the simulation plot (all microphones array in the 289: %vehicle cavity) and view the mode shapes. 290: function bt_simul_Callback(hObject, eventdata, handles) 291: fig=handles.figure1; 292: dcm_obj = datacursormode(fig); 293: c_info = getCursorInfo(dcm_obj); 294: 115 CHALMERS, Master’s Thesis 2007:149 295: figure(2); 296: cla; 297: hold on; 298: 299: if (get(handles.empty_box,’Value’) == get(handles.empty_box,’Max’)) 300: config_simul(’empty’,’b’,c_info) 301: end 302: 303: if (get(handles.fs_box,’Value’) == get(handles.fs_box,’Max’)) 304: config_simul(’front_seats’,’r’,c_info) 305: end 306: 307: if (get(handles.rs_box,’Value’) == get(handles.rs_box,’Max’)) 308: config_simul(’rear_seats’,’g’,c_info) 309: end 310: 311: if (get(handles.cpt_box,’Value’) == get(handles.cpt_box,’Max’)) 312: config_simul(’carpets’,’k’,c_info) 313: end 314: 315: if (get(handles.rs_prcl_box,’Value’) == get(handles.rs_prcl_box,’Max’)) 316: config_simul(’Rs_parcel’,’m’,c_info) 317: end 318: 319: if (get(handles.fs_rs_prcl_box,’Value’) == get(handles.fs_rs_prcl_box,’Max’)) 320: config_simul(’Fs_Rs_parcel’,’c’,c_info) 321: end 322: 323: if (get(handles.fs_rs_prcl_cpt_box,’Value’) == ... 324: get(handles.fs_rs_prcl_cpt_box,’Max’)) 325: config_simul(’Fs_Rs_carpets_parcel’,’y’,c_info) 326: end 327: 328: if (get(handles.ip_box,’Value’) == get(handles.ip_box,’Max’)) 329: config_simul(’ip’,’r’,c_info) 330: end 331: 332: if (get(handles.ip_fs_box,’Value’) == get(handles.ip_fs_box,’Max’)) 333: config_simul(’ip_fs’,’b’,c_info) 334: end 335: 336: if (get(handles.ip_rs_box,’Value’) == get(handles.ip_rs_box,’Max’)) 337: config_simul(’ip_rs’,’g’,c_info) 338: end 339: 340: if (get(handles.ip_rs_parcel_box,’Value’) == ... 341: get(handles.ip_rs_parcel_box,’Max’)) 342: config_simul(’ip_rs_parcel’,’m’,c_info) 343: end CHALMERS, Master’s Thesis 2007:149 116 344: 345: if (get(handles.ip_fs_rs_parcel_box,’Value’) == ... 346: get(handles.ip_fs_rs_parcel_box,’Max’)) 347: config_simul(’ip_fs_rs_parcel’,’c’,c_info) 348: end 349: 350: if (get(handles.ip_carpets_box,’Value’) == get(handles.ip_carpets_box,’Max’)) 351: config_simul(’ip_carpets’,’k’,c_info) 352: end 353: 354: if (get(handles.ip_fs_rs_carpets_parcel_box,’Value’) == ... 355: get(handles.ip_fs_rs_carpets_parcel_box,’Max’)) 356: config_simul(’ip_fs_rs_carpets_parcel’,’y’,c_info) 357: end 358: 359: if (get(handles.ip_sealed_box,’Value’) == get(handles.ip_sealed_box,’Max’)) 360: config_simul(’ip_sealed’,’k’,c_info) 361: end 1: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 2: % Function to plot the graph(s) when the checkbox is checked. 3: function trim_check(x,y,z) 4: 5: load .\frequency.mat % To load the frequency array, fa. 6: %Longitudinal 7: axes(z.axes1); 8: hold on; 9: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_longitudinal_parcel’]) 10: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[y ’-.’]); 11: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_longitudinal’]) 12: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),y); 13: 14: %Lateral Fs 15: axes(z.axes2); 16: hold on; 17: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_lateral_fs’]) 18: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[y ’-.’]); 19: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),y); 20: 21: %Lateral Rs 22: axes(z.axes3); 23: hold on; 24: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_lateral_rs’]) 25: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[y ’-.’]); 26: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),y); 27: 28: %Lateral Parcel 29: axes(z.axes4); 30: hold on; 117 CHALMERS, Master’s Thesis 2007:149 31: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_lateral_parcel’]) 32: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[y ’-.’]); 33: plot(fa,imag(Hxy(:,1,9)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),y); 34: 35: %Vertical 36: axes(z.axes5); 37: hold on; 38: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_vertical’]) 39: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),[y ’-.’]); 40: plot(fa,imag(Hxy(:,1,7)).*5.62.*(10 -̂2)./((4*pi*(7.5*10 -̂2)ˆ2)),y); 41: 42: %Longitudinal Trunk 43: axes(z.axes8); 44: hold on; 45: load([’.\lsp_data\’ x ’\lsp_ect_mic_meas\c1_’ x ’_trunk_long_lateral’]) 46: plot(fa,imag(Hxy(:,1,2)).*5.62.*(10 -̂2)./((4*pi