Road load analysis

摘要

Severe loading in a tire/suspension system arises when a rolling tire impacts an obstacle, such as a curb or pothole. Forces and moments at suspension hard points are needed during an impact for component specification, component durability, and endurance analysis. Today, automotive manufacturers and suppliers are promoting virtual prototyping by use of a computer--aided engineering (CAE) tool. CAE consists of a tire model, a suspension model, and a solver for equilibrium equations. The tire models can be classified either by a parametric tire model (PTM) or by a finite element tire model. In the former tire model, tire stiffness is represented by a set of springs; tire forces and moments are estimated by Pajeka equations. This class of tire models is limited to modeling a vehicle's performance, such as ride and handling. In recent years, explicit dynamic modeling of a rolling tire impacting a road imperfection has been used to calculate forces transmitted to a suspension system. The tire model consisted of a single layer of shell elements; solid elements were considered for the tread cap. The beads were not considered in this tire model. In this analysis, ABAQUS Explicit was used to model the rolling and transient impact of a tire. ABAQUS Explicit's modeling results were compared to ABAQUS Standard's results. The comparison included the tire forces, footprint pressure distribution at a free rolling condition, and resonant frequencies. In addition, modeling results of a tire/suspension system traversing an obstacle were presented. The suspension components, except spring and shock, were modeled by rigid elements connected together.