Analysis of elliptical Hertz contact of steel wires of stranded-wire helical spring

摘要

A stranded-wire helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Because of the multilayer structure, the wear on the local area of the steel wires' surface is related to the elliptical contact between adjacent wires during working process. Based on Boussinesq potential functions and elastic half-space model, the contact area and surface pressure of elliptical Hertz contact were investigated. Moreover, these surface contact quantities are used to expand the calculation of subsurface stress relevant to elliptical contact. It is found that the greater contact angle of two contact wires, the smaller contact area and greater maximum contact pressure. Meanwhile, the magnitude of subsurface von Mises stress is much higher when the contact angle increases.