Structural Optimization and Lightweight Design of Commercial Vehicle Thrust Rod based on Finite Element Analysis

As a key load-bearing component in the balanced suspension of commercial vehicles, the structural reliability and lightweight design of the thrust rod are of great significance for improving vehicle handling stability, reducing fuel consumption, and achieving the “dual carbon” goals. The traditional 42CrMo forging structure often has weight redundancy due to over-design, and its poor welding performance makes it prone to stress concentration and fatigue cracks. To address these issues, this study focuses on the thrust rod made of 42CrMo material. Based on the finite element theory and mathematical analysis methods, a parametric model was established using UG software, and the structural performance improvement and lightweight design were realized through static and dynamic characteristic analysis and multi-objective optimization. In the research, the UG/NX platform was used to construct an accurate 3D geometric model, and the load parameters under typical working conditions were determined through kinematic analysis. The NX Nastran solver was employed for static and modal analysis to identify the weak structural links and redundant areas. During the optimization stage, the UG topology optimization toolbox was integrated, with weight reduction as the core objective. Combined with the Response Surface Methodology （RSM）, mathematical modeling and derivation were conducted to obtain the optimal structural parameters. After optimization, the maximum stress of the thrust rod decreased from 149.15 MPa to 131.99 MPa, a reduction of 11.5%; the weight was reduced by 1.45%; and the safety factor increased from 6.23 to 7.04. Modal analysis showed that the first six natural frequencies of the optimized structure are far from the typical excitation frequencies of commercial vehicles, effectively avoiding the risk of resonance. Bench tests further verified that the strength and fatigue life of the optimized structure meet the design requirements. This study provides a scientific basis for the design of commercial vehicle thrust rods through a simulation-driven optimization method, and also offers new ideas for the development of lightweight technology in the industry. In the future, combining composite materials and additive manufacturing processes can further break through the limitations of traditional forging and realize more efficient lightweight design.