Stress Analysis of Coil Spring

Abstract

Various kinds of springs such as herical springs have space curved center lines, but their designing formulae, especially stress analysis methods, have not yet been established, and causing serious problems for industry.
We applied Wittrick's eguation based on the space curved rod theory to the analysis of the stress distribution across the cross-section of various type of herical coil springs. Moverover, since it is difficult to solve a set of there differential equations, we approximated it using a simple and a general finite differential methods, even if the exactness is last a little.
On the compression problems of coil springs with perfectly grinded ends and without grinded ends, we clarified all boundary conditions and contact conditions at the end turns. Furthermore, we demonstrated the propriety of this analysis.