Strength-Based Design Analysis of a Damaged Engine Mounting Bracket Designed for a Commercial Electric Vehicle

This study describes a strength-based design analysis protocol by means of finite element analysis (FEA) for a damaged engine mounting bracket in a converted electric vehicle. The mounting bracket considered in the study is a product specifically designed and manufactured for a converted electric vehicle and failed during conventional operation of the vehicle. Thus, design improvement/revision (redesign) on the bracket geometry was investigated. In this context, to prevent such undesired failures, strength-based design features such as deformation behaviour and stress distribution under projected loads on the bracket should be properly described; however, an accurate description of these features of the bracket may become a complex experimental problem to be solved by designers. This study described redesign of the strength-based design features of the engine mounting bracket through finite element analysis under torsional loading generated by the electric engine that was determined to be the reason for the failure and thus the motivation to realise a safer design. Visual and numerical results obtained from the simulation revealed a clear understanding of the failure behaviour of the bracket and therefore enabled an informed approach to the redesign stage. The initial FEA of the part design mapped the damage regions on the part geometry and indicated the stress magnitudes that were more than the material's stress limits. The comparison of the failure plots and numerical data obtained from this initial FEA and physically damaged part was consistent. This concluded that the FEA satisfactorily exhibited the deformation behaviour and the main reason for the failure was insufficient geometry thickness and notch effect against pre-defined loading conditions. Therefore, the main design improvement was realised on these geometric features. Subsequently, the final FEA highlighted that the redesign would enable safe operation. This work contributes to further research into usage of numerical method-based deformation simulation studies for the mounting elements used in customised electric vehicles.