Analysis of mechanical behaviors of internal helically wound strand wires of stranded wire helical spring

Abstract

A stranded wire helical spring is a cylindrical helical spring, which is usually composed of an optional core wire and several layers of twisted external wires. The mechanical behavior of the internal helically wound strand wire is critical to determining the spring performance. Based on the previous studies of the mechanical properties of wire rope, a mathematical model to calculate the curvature of the helically wound strand wires, twist, and contact force among the adjacent wires of strand wires spring is established when the spring is subjected to axial load. The proposed kinematics is based on the assumption that there is no friction among the adjacent wires. Furthermore, a parametric study of factors influencing the curvature, twist, and contact force, such as the helix angle of spring and strand and deformation types, is committed for understanding of the mechanical characteristics of the helically wound strand wires with different geometric parameters. It is found that the curvature and twist are strongly dependent upon the two angles. Moreover, this study can provide significant reference for the design and manufacturing of the spring to control the contact force among external wires.