Structural Optimization and Fatigue Life Assessment of Connecting Rod Using Topology Optimization and Finite Element Analysis

¹ This email address is being protected from spambots. You need JavaScript enabled to view it. , Department of Mechanical Engineering, National Engineering College, Kovilpatti, 628503, Tamil Nadu
² *This email address is being protected from spambots. You need JavaScript enabled to view it. , Department of Mechanical Engineering, National Engineering College, Kovilpatti, 628503, Tamil Nadu

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 3 March 2026

Abstract

The connecting rod is a critical part of the engine to transfer forces between the piston and crankshaft by withstanding continuous cyclic loading. In this study, a standard connecting rod was modelled and analyzed using ANSYS for deformation, stress behavior, safety factor, and fatigue life. Duralumin was selected as the material, since it contains a high strength-to-weight ratio and good resistance to fatigue, making it suitable for lightweight reciprocating parts. Realistic boundary conditions were then applied by fixing the big end and applying an axial compressive load at the small end. Further topology optimization was performed to remove low- stress regions, which showed significant mass reduction. While higher stresses and a reduced safety factor were observed for the optimized model, the fatigue life remained the same due to the preservation of critical load paths. The final design has maintained an acceptable FoS, and using a slightly lower FoS is quite reasonable when weight reduction is of primary importance.