The Analysis of Static Stress in Coil Springs with Nonlinearity

Abstract

The load-deflection relation and stress characteristics of coil springs with variable mean coil radii, variable wire diameters, and variable pitch angles were analyzed by using the finite element method. Nonlinear effects due to contact between the wire and the seat and or/ due to contact between adjacent coils were considered in the analysis. Numerical calculations carried out for a barrel-shaped spring, a conical spring, and a variable pitch spring indicate that the stresses in the contact part of the wire, particularly near the terminating contact point, depend upon deflections of the springs. This result suggests that the conventional assumption for the stresses of the contact part of the wire is not reasonable. Calculated results area well corroborated with the experimental results.