Test setup and methodology for thermo-mechanicalfatigue in a multilayered polymer system

Sammanfattning

This project addresses the challenge of thermomechanical fatigue in the insulation systems of high voltage electricmotors, with a focus on applications in heavy duty vehicles such as trucks. These motors operate under demandingconditions, including high thermal loads, frequent load cycles, and extended usage. Failures in the insulation sys-tem can cause significant motor damage, making insulation reliability a critical factor for sustainable transportation.To support the development of more robust insulation materials, a small modular version of an electric motorstator, called a statorette, was developed. The statorette enables controlled thermomechanical fatigue testing byheating hairpins with direct current in repeated thermal cycles. By periodically evaluating the insulation condition,the setup provides valuable insight into degradation mechanisms and informs the design of future hairpin configu-rations and insulation materials.A complete test system was constructed with temperature sensors and control equipment to enable safe and represen-tative testing based on truck-driving conditions. The design prioritizes ease of assembly, cost efficiency, standardizedmanufacturing, and flexibility to support a variety of hairpin configurations. During the product development phase,simulations were used to confirm that the statorette behaves in a manner consistent with a full-sized stator.Although this study focuses only on degradation caused by thermomechanical fatigue and does not account forthe effects of alternating current or electromagnetic forces, it makes a meaningful contribution to understandinginsulation aging. The developed test rig provides a valuable tool for evaluating insulation systems and supports thedevelopment of more reliable and efficient electric motors for future heavy-duty electric vehicles.