Modelling and Validation of Joint Properties for NVH Simulation Model of an Electrified Passenger Vehicle Drivetrain

Abstract


 
 
 The constantly changing automotive market, which is characterized by the progressing electrification of vehicles, presents challenges with respect to the acoustic behaviour of powertrains. As indicated frequently, the characteristic noise of electric cars differs from that of conventional drives. In particular, energy dissipation of the assembled housing parts from material and joint damping; is an important aspect. In modelling the NVH behavior of electric vehicles or drivetrains in general, the breakdown of global material and local joint damping is not yet state of the art. Instead, measured global modal damping values from similar constructions are frequently used. Often, a constant degree of damping is defined for all modes. However, moderate changes in the geometry of components or in the load level can lead to severe fluctuations in the damping. In order to improve predictability and to be able to estimate the effects of constructive changes in natural frequency, mode shape, and damping, the goal will be to take into account the global material and local joint damping separately. For that, a local model which is able to take the joint properties into account has to be developed. The analytical based Iwan model for the contact interface was expanded upon to facilitate model updating against forced response measurements on a simple mass spring structure in one dimension and to extend the model from one-dimensional to three-dimensional.