The Impact of Rib Geometry for Electric Drive Units on the Radiated Sound
| dc.contributor.author | Malm, Oskar | |
| dc.contributor.author | Wurzinger, Jakob | |
| dc.contributor.department | Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper | sv |
| dc.contributor.department | Chalmers University of Technology / Department of Mechanics and Maritime Sciences | en |
| dc.contributor.examiner | Johansson, Håkan | |
| dc.contributor.supervisor | Lennström, David | |
| dc.contributor.supervisor | Cederlund, Johan | |
| dc.date.accessioned | 2024-06-14T06:19:39Z | |
| dc.date.available | 2024-06-14T06:19:39Z | |
| dc.date.issued | 2024 | |
| dc.date.submitted | ||
| dc.description.abstract | In recent years, the automotive industry has been moving towards electrification of vehicles. One of the most essential parts of electric vehicles are the electric drive units or EDUs, which convert electrical energy into mechanical energy that drive the wheels. An EDU typically consists of several parts, such as an electric motor, gearbox, and differential, which are encapsulated in an aluminum housing. The housing has ribs, that can increase the stiffness or casting quality of the housing. These design requirements are to fulfill the crash safety requirements, as well as noise, vibration, and harshness (NVH) requirements in terms of structure born noise. The combination of these requirements, can result in ribs which has be observed to in some cases, produce unwanted airborne sound. To investigate how the rib geometry affect the sound radiated from ribs, a number geometry of variations was performed on four different base models. This includes curvature of the outer edge, dimensions (area), angles, etc. These variations were then simulated by meshing the CAD models in ANSA, calculating the nodal displacement of the surface nodes in NASTRAN using a velocity boundary condition, and mapping the displacements to the air using an acoustic mesh in Actran. The simulations were performed for frequencies between 100 Hz and 6 kHz. Finally, the radiated power, radiation efficiency, and mean square velocity was saved from the simulations and analyzed for each geometrical variation. The first bending mode was found to have a large impact on the radiated sound and has a strong connection to the bending stiffness of the rib. The peak mean square velocity always occurs at the first bending mode however, the radiation efficiency does not show any general pattern and is therefore difficult to predict. From the simulations, it could be concluded that the area of the rib has the largest impact on the radiated power, which is a clear indication to design as small ribs as possible. It could also be shown that for some ribs, it is beneficial in terms of reducing the radiated power, to add a small curvature to the outer edge. A relationship between the dimensions of the ribs and the thickness of the rib was also found, where some thickness increases or decreases the radiated power for ribs with same dimensions. Finally, two adjacent ribs can interact to increase the radiated power significantly for some distances or angle between the ribs. | |
| dc.identifier.coursecode | MMSX30 | |
| dc.identifier.uri | http://hdl.handle.net/20.500.12380/307845 | |
| dc.language.iso | eng | |
| dc.setspec.uppsok | Technology | |
| dc.subject | Acoustic simulations | |
| dc.subject | Actran | |
| dc.subject | Electric driveline | |
| dc.subject | Electric drive unit | |
| dc.subject | Radiation efficiency | |
| dc.subject | Ribbed structures | |
| dc.subject | Structural vibrations and sound radiation | |
| dc.title | The Impact of Rib Geometry for Electric Drive Units on the Radiated Sound | |
| dc.type.degree | Examensarbete för masterexamen | sv |
| dc.type.degree | Master's Thesis | en |
| dc.type.uppsok | H | |
| local.programme | Mobility engineering (MPMOB), MSc |