Correlation of Modal Shaker Test Simulations with respect to Physical Measurements
Typ
Examensarbete på grundnivå
Program
Publicerad
2021
Författare
Hansson, Niklas
Karlsson, Philip
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Understanding, evaluating and testing vehicle dynamics is an area that is becoming more and more important as the car industry develops more advanced and complex systems every year. When a car manufacturer establishes their presence in what is known as the premium brand segment the secondary ride experience is of great importance. A smooth and comfortable secondary ride experience during different road conditions plays a big role in how the customer perceives the quality of the ride, and whether the car manufacturer meets the criterias to be classified as a premium brand. In order to ensure a good secondary ride the composition of the suspension components has to be chosen carefully with good validation. To find the right components such as bushings, tires and dampers, several different testing techniques are used at the Volvo Vehicle Dynamics Department, one of them being the modal shaker analysis. This analysis is done with a modal shaker rig test and a real vehicle which makes it both expensive and time consuming to try different component models. Due to the shaker test being highly repeatable and covers a large range in frequency and amplitude, it makes it a good candidate for correlation. If instead this modal shaker test could be conducted with a simulating software and still produce results with sufficient fidelity levels it could be used as a complement to the real rig test. In this thesis work the aim is to find modeling aspects for the simulated modal shaker event that affect the correlation between the simulation and real test. This is done by testing different types of bushing, tire and damper models in the simulation software Adams Car. The results are then processed in MATLAB and a comparison is made to establish the degree of correlation to the real rig test. During this work it could be established that the MATLAB functions used to estimate the modal parameters natural frequency and damping ratio were sufficient to achieve sufficient fidelity levels in correlation. The bushing model MXmount, tire model Ftire and damper model Advanced Damper model are in need of further investigation regarding their parameterization to capture their true beneficial effects.