Multi Domain Modeling of NVH for Electro-Mechanical Drives 2020-01-1584
Acoustics and vibrations are amongst the foremost indicators in perceiving the quality of drive units. Analyzing these factors is vital for improve the performances of electro-mechanical systems. This paper deals with the study of vibro-acoustic behavior concerning the drivetrain components using system modeling and Finite Element calculations. A generic simulation methodology within system modeling is proposed enabling the vibro-acoustic simulation of electro-mechanical drivetrains. Excitations for these systems mostly arise from the electric motor and mechanical gears. The paper initially depicts the system model for gear whining considering the associated nonlinearities of the mesh. The results obtained from the gear mesh submodel, together with the excitations resulting from the motor, aid in the comprehension of the forces at the bearings and of the vibrations at the housings. Furthermore, acoustical characterization of the variants is depicted by the examination of emitted acoustic pressures and intensities, which are calculated using the setups of acoustic finite elements. For the method verification, a three-stage gear model of an electro-mechanical drivetrain is developed. The simulation model allows studying rotational oscillations of the shafts, three-dimensional vibrations of gear parts and peripheral components and pressure fluctuations of the surrounding fluids. Eventually, the experimental validations for surface vibrations and acoustic fluctuations are performed with the aid of a laser vibrometer and acoustic camera. Finally, it is shown that the system level simulations allow for a better grasp of the vibrations and noise involved in the drivetrain assemblies.