Colloquia

Summary

This thesis presents a comprehensive redesign of powertrain housing side covers, weighing the potential benefits and risks associated with the proposed replacement. The current powertrain housing is constructed from an aluminum alloy. The materials under consideration for the redesign are short fiber thermoplastic composites utilized in injection molding processes.

The goal of this study is to determine the feasibility of and impact to the redesigned housing covers on current and future electric powertrains. The potential benefits of replacing aluminum with thermoplastic composites include reduced overall costs, noise, vibration, and harshness (NVH) benefits, reduced life cycle impact, increased thermal efficiency, integration of functions, and reduction of processing steps. The potential risks include competing demands for specific properties and NVH requirements, increased total cost, increased life cycle impact, material properties and design uncertainty, integration complexity, electromagnetic compatibility, and interface part reconstruction.

The potential risks and benefits were validated through a design study. The design study was performed with two suppliers, and after the composite design was completed, one of two suppliers was chosen to continue with the project. The material chosen for the concepts was a PA66 GF50, due to its favorable structural properties and performance indices.

Thermomechanical simulations indicated that the thermoplastic composite housing cover exhibited slight improvements in thermoefficiency compared to the aluminum variant. However, the results of the NVH simulations were inconclusive. The cost analysis demonstrated that the costs decreased for the side that is not subjected to significant loads and increased for the side that bears the majority of the load. In terms of electromagnetic compatibility, the importance of electromagnetic interference shielding was identified as a significant factor. This aspect is complex and may involve costly measures. Testing the powertrain on two dynamometers for thermo-efficiency and NVH to validate the simulations demonstrated that the powertrain met the desired specifications.

The future outlook outlines a systematic approach to bring the housing cover into mass production, while also identifying potential risks to be overcome. The outlook is based on design, production, material, and process considerations. The thesis concludes with the answering of the research questions.