Research and Verification on the Nonlinear Characteristics of Wheel/Rail Equivalent Conicity

Abstract

This paper aims at the influence of nonlinear equivalent conicity with the same nominal equivalent conicity on EMU (Electric Multiple Units) motion attitude based on the wheel/rail nonlinear contact theory. Four worn wheels were considered in this paper, it was found that wheels with same normal equivalent conicity had significant differences on wheel/rail interactions. A new evaluation method was proposed: based on statistics data, the wheel/rail contact condition was identified with “nonlinear factor” and “nonlinear equivalent conicity” derived by equivalent conicity range from 1 mm to 6 mm. Both field tests and simulations indicated that the normal equivalent conicity couldn’t accurately reflect the wear condition of wheel/rail contact. The proposed new indexes based on nominal equivalent conicity and the slope of equivalent conicity curve would reflect the nonlinear characteristics of wheel/rail contact more accurately. It is an effective method to evaluate the relationship between wheel/rail nonlinear contact condition and vehicle dynamic performance.