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This paper presents a validation method of vehicle suspension models to improve the accuracy of vehicle simulation model and a prediction method of vehicle handling characteristics. Suspension model validation was performed by comparing the simulation results of front and rear suspension model to the suspension quasi-static test results about wheel alignment characteristics like toe, camber, caster, roll steer, lateral force compliance steer and ride rate etc., and the procedure is shown. Suspension test results have been obtained by using suspension parameter measuring machine. For the predictions of handling maneuvers, total vehicle model is built by combining of these validated front and rear suspension models and numerical tire model based on the rig test. Suspension modeling and handling maneuver simulations are performed using general purpose dynamics and kinematics analysis code DADS.

The dynamic behavior of an epicyclic gear train (EGT) with planet gears supported by journal bearing has been analyzed. The nonlinear stiffness of the gear teeth mesh was considered in the dynamic equations. Hydrodynamic bearing analysis on the fluid film between the planet gears and the shafts was executed to calculate the non-linear equivalent stiffness and damping coefficients. Interactive reactions between the gear dynamics and the bearing characteristics has been included. By this analysis, the gear tooth mesh forces at the sun/planet (S/P) and the planet/ring (P/R) gear meshes, the loci of the sun gear as well as planet and ring gear center, and bearing forces on the planet gear shaft have been calculated. Experiments have also been carried out to compare the calculated results using a simple star type planetary gear train. Calculated results have good correlation with experimental values.