Topology optimization of a ratchet compensation structure subject to periodic constraints

The railway pantograph-catenary system employs a ratchet compensation device to sustain the tension of the contact wire. However, the excessive weight associated with the ratchet structure adversely affects the performance of the compensation device. An optimization design aimed at lightweight optimization of the ratchet wheel structure can enhance the system’s agility, improve material utilization, and reduce costs. This study uses a finite element model to establish an equivalent load model for the ratchet under service conditions and analyzes its load-bearing state. An optimization model was created and solved using ANSYS Workbench. The topological optimization configurations were compared under unconstrained conditions and four different periodic constraint scenarios. Following this, the structure was redesigned based on the topological optimization results, and a simulation analysis was conducted to compare the reconstructed model with the original model. The comparison results indicate that the masses of all four optimized models have been reduced by more than 10 %. Additionally, under conditions of a fully wound compensation rope, the maximum stress has decreased by over 20 %, leading to a more uniform stress distribution and improved overall performance. The topology optimization and redesign method based on periodic constraints offers a viable engineering solution for the lightweight design of the ratchet structure. • An equivalent load model for the ratchet wheel was developed by the differential element method. • The reaction forces from simulation were compared with theoretical results, showing errors of 2.5 % in F x and 3.5 % in F y . • A topology optimization model for the ratchet wheel body was developed and optimized accordingly. • Based on topology optimization, four models were developed, significantly enhancing the ratchet wheel's performance.