Prediction of dynamic characteristic of laminated structures with contact and frictional forces

Abstract

As electric vehicles become increasingly popular, motor noise can become a problem. In particular, the vibration characteristics of motor stators contribute significantly to noise, so there is a growing need to understand the vibration characteristics of stators and to develop models to predict them. Generally, a stator is a laminated structure consisting of several hundred electromagnetic steel plates stacked and joined by various methods such as caulking, welding, bonding, and bolting. Since contact and friction forces are generated between the steel plates in this laminated structure, the nonlinear nature of the structure makes it difficult to determine the vibration characteristics and prediction accuracy is low. Although it is theoretically possible to determine the effects of contact and friction using nonlinear finite element analysis, there are problems such as the calculation not converging when the number of layers increases and the calculation results being dependent on the calculation parameters. Therefore, in this study, the method proposed in a previous study to model the effects of contact and friction when two steel plates are bolted together using spring elements is applied to a laminated structure consisting of several hundred electromagnetic steel plates to verify its prediction accuracy.