Static Structural Analysis, Weight Optimisation, and Fatigue Life Estimation of Conventional Steel and Composite Leaf Springs for Light Commercial Vehicle Suspension Using ANSYS Finite Element Analysis

Abstract

Leaf springs are one of the oldest and most mechanically efficient suspension components used in commercial vehicles, absorbing road-induced shocks and maintaining tyre contact through deflection of the spring leaves. Conventional multi-leaf springs fabricated from EN 47 (55Si2Mn90) spring steel are heavy — typically 18–25 kg per spring — contributing significantly to vehicle unsprung mass, which directly affects ride comfort, road holding, and fuel consumption. Fibre-reinforced polymer (FRP) composite materials offer the potential for dramatic weight reduction — up to 70 percent — while maintaining or exceeding the structural performance of steel springs, owing to their high specific strength and specific stiffness. This paper presents a comprehensive finite element analysis (FEA) study of a multi-leaf spring designed for a 4-tonne capacity light commercial vehicle (LCV), comparing EN 47 steel with four composite laminate configurations: carbon fibre reinforced polymer (CFRP) with [0/90/0]s and [±45]s ply arrangements, and glass fibre reinforced polymer (GFRP) with equivalent lay-up sequences. The FEA is conducted in ANSYS Mechanical 2024 R2 using SHELL281 layered shell elements for composite springs. Mesh convergence is verified and results validated against analytical beam theory. Under the full rated load of 40 kN, maximum deflection, Von Mises stress distribution, static safety factor, spring rate, and mass are compared across all five configurations. Fatigue life estimation uses the Goodman modified Soderberg diagram with ANSYS Fatigue module predictions. Results show that CFRP [0/90/0]s offers the best overall performance: 67.9 percent mass reduction (from 18.62 kg to 5.98 kg), Von Mises stress 26.1 percent lower than steel despite higher deflection, static safety factor of 2.34, and fatigue life of 8.62 × 10⁷ cycles compared to 1.84 × 10⁶ for steel at the same loading — establishing CFRP cross-ply as the recommended replacement for steel in weight-critical LCV applications.

Cite as:

Sayyad Asim J. (2026). Static Structural Analysis, Weight Optimisation, and Fatigue Life Estimation of Conventional Steel and Composite Leaf Springs for Light Commercial Vehicle Suspension Using ANSYS Finite Element Analysis. Recent Trends in Production Engineering, 9(2), 41–49. https://doi.org/10.5281/zenodo.21802900