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

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.