Topological Optimization Design of Automobile Suspension Swing Arm Based on PEEK Material

Abstract

To achieve a lightweight design of the vehicle suspension lower control arm under complex road load conditions, a topology optimization model based on the variable-density method was established, with the structural stiffness of the suspension system during vehicle operation as the constraint and minimum mass as the objective. Based on the optimization results, the structure of the lower control arm was redesigned, and stiffness and strength checks were performed within the designated design region. The original steel material was replaced with lower-density Polyether Ether Ketone (PEEK), and the complex geometry was manufactured using Fused Deposition Modeling (FDM), increasing the feasibility of realizing the topology-optimized design. In this study, only material specimens underwent physical testing; the final control arm was not experimentally tested and was evaluated solely through simulation. Because FDM forming quality is influenced by printing parameters, tensile tests were conducted on PEEK specimens printed under different parameter settings, and the optimal parameters were determined to be a layer height of 0.2 mm, a build-plate temperature of 120 °C, and a tetrahedral infill pattern. Specimens printed under these optimal conditions were subsequently subjected to thermal-holding treatments to investigate the effects of different heat-holding processes on tensile strength. By comparing mechanical properties before and after heat treatment, the optimal condition was identified as 340 °C for 2 hours. A multibody dynamics simulation was employed to determine the actual loading conditions of the lower control arm during vehicle operation. Static structural analysis of the maximum load case was then performed to identify stress concentrations and guide the topology optimization. Under the requirement of maintaining adequate mechanical performance, material usage was minimized, ultimately reducing the mass of the lower control arm by 49.05% and achieving substantial lightweighting.