Design of Rail Variable Cross Section Grinding Profile Based on NURBS Surface

Abstract

To eliminate the abnormal wear and shaking caused by the standard grinding method in curved rails, and improve the matching performance and passing ability, a Non-Uniform Rational B-Spline (NURBS) -based design optimization method is proposed in this paper, which is for the variable cross section grinding profile design of curved rails. Compared with the standard rail cross section profile, the effective wheel–rail contact length of the optimized curved section increases. The increases in the wheel–rail contact density of the gently curved section, the gently rounded point, and the rounded curved section are 161.08%, 68.57%, and 271.60%, respectively. Therefore, the wheel–rail contact relationship and the wheel–rail matching performance are significantly improved. The abnormal wear problem caused by the wheel–rail matching performance is reduced. In addition, compared with the standard grinding profile, the maximum reductions in the derailment coefficient, rate of wheel load reduction, wheel–rail transverse force, wheel–rail vertical force, wheel offset angle, and maximum wear index of the optimized designed profile in the curved section are 9.23%, 14.72%, 11.39%, 9.76%, 6.03%, and 12.03%, respectively. Therefore, the dynamic performance is significantly improved. Furthermore, the trains’ curve-passing ability improved, and the shaking-car phenomenon was suppressed. Finally, when the optimized rail grinding profile is adopted, the reduction in the rail grinding removal amount for the transition curve section, slow circular point, and circular curve section reaches 43.41%, 43.39%, and 61.94%, respectively. Therefore, the lifespan of the rail in the curve section is prolonged.