Optimization of Laminating Angles for Skirt Panels of EMUs Front Using Composite Materials Based on the Cheetah Optimizer

With the development of composite materials, their lightweight and high-strength characteristics have caused more widespread use from aerospace applications to automotive and rail transportation sectors, significantly reducing the energy consumption during the operation of EMUs (Electric Multiple Units). This study aims to explore the application of composite materials in the lightweight design of EMU front skirts and proposes a design method based on three-dimensional Hashin failure criteria and the Cheetah Optimizer (CO) to achieve maximum lightweight efficiency. The UMAT subroutine was developed based on the three-dimensional Hashin failure criteria to calculate failure parameters, which were used as design parameters in the CO. The model calculations and result extraction were implemented in MATLAB, and the Cheetah Optimizer iteratively determined the optimal laminating angle design that minimized the overall failure factor. After 100 iterations, ensuring structural integrity, the optimized design reduced the weight of the skirt panel by 60% compared to the original aluminum alloy structure, achieving significant lightweight benefits. This study provides foundational data for the lightweight design of EMUs.