Dynamic Analysis and Design Optimization of Automobile Chassis Frame Using FEM

Abstract

In this paper, dynamic analysis of a ladder chassis frame has been done using Ansys. First, modal analysis of the chassis was done using structural steel material. The first six nonzero natural frequencies and their corresponding mode shapes were extracted. It was observed that the second natural frequency of the chassis was close to the engine excitation frequency at idling condition, and the fifth natural frequency was close to the engine excitation frequency at high-speed cruising condition. Thus, the chassis may experience structural resonance at these conditions. The chassis design was optimized so as to obtain the natural frequencies in the desired range, and avoid the possibility of resonance. A harmonic response analysis was done on the original and optimized chassis to check the response under a harmonic force.