Calculation of Influencing Number of WheelRail NonHertz Contact Using Finite Element Method

Abstract:

When wheel/rail contact problems are solved using nonHertz contact theory, the influencing numbers have more important effect on wheel/rail contact stress and contact patch. When a contact between wheel flange and rail gauge angle occurs, the influencing number of nonHertz contact theory based on elastic half space hypothesis is not applicable. Based on elastic full space hypothesis, a finite element method was presented to calculate wheel/rail contact influence number of nonHertz contact theory, and the nonHertz contact model was innovatively revised. As an example of wheel/rail contact profile of the CHN75 standard rail and LM standard wheel in China, under the calculation of high efficiency, two wheel/rail contact models (revised nonHertz method and wheel/rail profile partition model P_M (Partition Model) were used to calculate the wheel/rail normal contact stress and contact patch area when lateral displacement of the wheelset ranged from 0 mm to 8 mm. The results show that the influencing number calculated by finite element method is larger than that obtained by using BossinisqeCerruti formula. And the result calculated by finite element method on the rail gauge corner is larger than that on the top of the rail. The normal stress calculated by revised nonHertz theory is larger than that calculated by the P_M model, and the change of the normal contact stress and contact patch area calculated by two wheel/rail contact model is almost the same with the increase of the lateral displacement of the wheelset. When the lateral displacement of the wheelset is 0 to 4 mm， the maximum of the wheel/rail contact patch area is 173.75 mm2 and the wheel/rail contact profile is best matched. With the increase of the lateral displacement of the wheelset, the contact between the wheel flange and rail gauge corner will be produced and the wheel/rail contact area decreases while the normal contact stress increases dramatically.