Failure Analysis of the Half-Shafts Belonging to a Three-Wheeled Electric Vehicle

Abstract

In the electric vehicles studied, the driven wheels and the differential, which are responsible for the transfer of power and rotational motion, are connected by half-shafts. The failure of two half-shafts in the rear gearbox of a three-wheeled electric vehicle, popularly known as a Tuk Tuk, is examined and evaluated in this research. Therefore, the primary goal of this work is to look at the factors that contribute to the failure of the aforementioned components. Visual examination and fractographic analysis were performed utilizing optical and scanning electron microscopes to investigate the half-shafts’ mode of failure. Samples from both half-shafts were obtained for tensile testing, metallographic examination, chemical composition analysis, and fracture surface analysis. According to visual examination, reversed bending fatigue, occurring simultaneously with torsion loading, caused the fracture in the half-shaft to the left of the differential (rear view). Analysis of the fracture surface of the half-shaft to the right of the differential revealed that it resulted mainly from bending fatigue loading. Moreover, regarding the mechanical design safety of the half-shafts, calculations were performed considering different trajectories, limit speeds, and different design criteria. Finally, some recommendations are drawn to improve the design safety of this mechanical component.