Fatigue Life Prediction on Rough Road Using Full Vehicle Co-simulation Model with Suspension Control 2010-01-0952

A full vehicle multi-body dynamic (MBD) model with suspension control system is developed for fatigue life prediction under rough road condition. The model consists of tires, a trimmed body, heavy attached parts, powertrain, suspension, joints, and a driver model, and includes a suspension control system that varies characteristics of the suspension according to the rough road inputs. For tires, a commercial MBD tire model is employed with identifiable parameters. The models are simulated to run on the optically measured road surface of the proving ground. Apart from the trimmed body, several important heavy attached parts are modeled separately, that represent dynamic behavior that induces complex body input load. These parts, along with suspension and powertrain systems are connected to the body using nonlinear elements such as joints, springs, and dampers. Contact conditions are used to represent mount bushing, hood lock, stopper rubber, etc. An in-house integrated driver model with variable gain parameters controls the engine torque, braking force and steering angle and thereby adjusts vehicle speed and designated road pass for the vehicle to follow within the testing course. To evaluate the accuracy of the simulation method, the results are compared with experimental measurements. There was good correlation observed between the simulation and the test result. The validity of the model was further verified by applying it to an analysis of the vehicle hood on a corrugated road. The simulation method was able to successfully predict the unusual dynamic response of the hood.