In this paper, fatigue life of coil springs was investigated as failure due to high cyclic loading during their service life is more common. For this purpose, two exclusive rear coil compression spring geometries were investigated using material type - silicon-chromium steel SAE-AISI 9254 for this application. For these design models, the effect of changing component geometry using varying pitch arrangements of coils were examined to understand their structural durability and ability to withstand cyclic loading conditions. A finite element model based on industry standard designs was created to simulate real-life spring performance. In this study, the varied pitch designs were subjected to lower stresses in static analysis and have longer life estimates in the fatigue analysis. This confirms that a varied pitch can improve the performance of a coil spring.  The result shows that design-1 incorporated a pitch design that reduced pitch at the centre coils of the spring performed better. 

Keywords: Fatigue Analysis; Rear Coil Compression Springs; SAE-AISI 9254; Automobiles