Dynamic Stress Correlation and Modeling of Driveline Bending Integrity for 4WD Sport Utility Vehicles

Reducing the high cost of hardware testing with analytical methods has been highly accelerated in the automotive industry. This paper discusses an analytical model to simulate the driveline bending integrity test for the longitudinal 4WD-driveline configuration. The dynamic stresses produced in the adapter/transfer case and propeller shaft can be predicted analytically using this model. Particularly, when the 4WD powertrain experiences its structural bending during the operation speed and the propeller shaft experiences the critical whirl motion and its structural bending due to the inherent imbalance. For a 4WD-Powertrain application, the dynamic coupling effect of a flexible powertrain with a flexible propeller shaft is significant and demonstrated in this paper.

Three major subsystems are modeled in this analytical model, namely the powertrain, the final rear drive, and the propeller shafts. Component and subsystem finite element model correlation with modal test data was first conducted. Then the system finite element model was correlated to the test-rig setup. Inherent imbalance was analytically included in the propeller shaft model and the whirl motion of propeller shaft was induced to simulate the testing procedure. Afterwards, the combination of nonlinear Multi-body System Simulation (MSS) with the linear Finite Element Analysis (FEA) in time domain for the evaluation of the dynamic interaction between several parts was used as a numerical tool. Finally, the new analytical capabilities of stress recovery for adapter/transfer case and propeller shaft were introduced. Available test results were used to validate the analytical model.