Design study of electric vehicle roll-cage obtained using modal analysis

Abstract

Understanding the dynamic behaviour of structures has become increasingly essential in the design process of any mechanical system. Modal factors like natural frequencies and mode shapes characterize the dynamic response of the structure and can be used for determination of the possible bending and torsion phenomenon. The Computer-Aided Drafting (CAD) model plays an important role in the design and development phases of an electric vehicle. For doing Finite Element Analysis (FEA) using software CAD model has to be imported so that after conversion Finite Element (FE) model can be solved. In the present case the CAD model is imported in HyperMesh. The FE model is generated and solved by using OptiStruct. Ignoring the first six natural frequencies and mode shapes due to its association with six degrees of freedom, subsequent six natural frequencies and mode shapes are proposed for an electric vehicle roll-cage. We can learn even more from CAD geometry and mode shapes in every direction about its stiffness and weight. Once we know our design baseline, we can use a software simulation to use a design study and improve its performance. We have considered the pipe diameter, thickness, tube width and height as main design parameters which needs to be optimized. In this paper, we optimized all these design parameters to make driver comfortable during driving by increasing natural frequency of the roll-cage structure by 3.34 times the human body threshold.