Static contact mechanism between serrated contact wheel and rail in rail grinding with abrasive belt

Abstract

Rail grinding with abrasive belt essentially appears as the complex nonlinear contact interaction between contact wheel, abrasive belt, and rail surface to realize flexible and efficient rail grinding, and in the grinding process, the higher grinding efficiency can be achieved with a serrated contact wheel. However, the contact mechanism between serrated contact wheel and rail is obscure. In this paper, a parametric contact model between serrated contact wheel and rail is established by setting the non-structural (grinding pressure and rotation angle) and structural parameters (helix angle, cogging ratio, etc.) of the serrated contact wheel. Then, the finite element simulation of contact behaviors under the changing conditions of various parameters is carried out to reveal the influences of the above parameters on the maximum contact stress, contact area, and rubber layer indentation depth. On this basis of the extension of the traditional Hertz contact theory and the calculation of the geometric structures of serrated contact wheel and rail, the mathematical model of the contact area is obtained and the ellipsoidal pressure distribution area and the stress concentration area are calculated and combined together to obtain the contact area pressure distribution model. The contact static test platform was designed and the errors between the theoretical and experimental lengths of the long and short axes of the contact area under a rotation angle of 0° were respectively determined as 7.3 % and 9.9 %, thus verifying the correctness of the established mathematical model. In addition, the theoretical and experimental results of the same points on the characteristic lines of the pressure distribution were obtained separately for the comparison. The comparison results proved the correctness of the mathematical model of pressure distribution.