Biomimetic topology optimization and structural evaluation of a manual transmission shift fork

Abstract This study evaluates the structural performance of a manual transmission shift fork using ANSYS Workbench and a biomimetic topology optimization framework. A 3D model of the original fork was created in SolidWorks, and its structural behavior was analyzed under different loading conditions with the finite element method (FEM). Stress and deformation results identified weak regions, guiding the redesign process. Inspired by the lattice architecture of Euplectella aspergillum , a biomimetic strategy was adopted to improve both durability and material efficiency. Lattice-based geometries were integrated into the fork design, enhancing stability under multiaxial loading. Topology optimization further redistributed material to achieve weight reduction without compromising strength. Under a 350 N load, the optimized design exhibited von Mises stress of 486.72 MPa compared to 41.18 MPa in the original, remaining below the yield strength of SAE 4140 steel. Total deformation rose from 0.0648 mm to 0.3753 mm but stayed within the elastic range. Fork volume decreased from 142.320 to 88.465 mm 3 , representing a 37.8 % reduction. These results demonstrate that biomimetic topology optimization enhances structural efficiency, reduces manufacturing costs, and supports fuel economy by lowering component weight.