Representing SUV as a 2D Beam Carrying Spring-Mass Systems to Compute Powertrain Bounce Mode 2021-01-1116

Accurate prediction of in-vehicle powertrain bounce mode is necessary to ensure optimum responses are achieved at driver’s touch points during 4post shake or rough road shake events. But, during the early stages of vehicle development, building a detailed vehicle finite element (FE) model is not possible and often powertrain bounce modes are computed assuming the powertrain to be a stand-alone unit. Studies conducted on FE models of a large SUV with body on frame architecture showed that the stand-alone approach overestimates the powertrain bounce mode. Consequently, there is a need for a simplified version of vehicle model which can be built early on to compute powertrain modes. Previously, representing all the major components as rigid entities, simplified unibody vehicle models have been built to compute powertrain modes. But such an approach would be inaccurate here, for a vehicle with body on frame architecture due to the flexible nature of the frame (even at low frequencies). To address this issue, using theoretical beam formulations, a novel approach was proposed wherein the body on frame vehicle was represented as a two dimensional (2D) continuous beam attached to multiple spring mass systems. Using such a representation of body on frame vehicle to compute powertrain bounce mode was not only unique, but also led to more accurate results compared to the stand-alone unit and hence can be used for predicting powertrain bounce modes during the early stages of vehicle development.