Nowadays, applying rail grinding has been worldwide recognized as the routine maintenance approach to improving the wheel-rail relationship, as well as extending the rail’s serving life. However, the traditional rail repair technology with the abrasive wheel or the milling cutter is getting harder to meet the increasing demand for high efficiency with high speed. In this paper, according to the engineering requirements and constraints, a new fast rail-grinding car based on open-structured belt grinding technology was designed for the corrugation treatment on high-speed railways. A corresponding simulation model was established and its dynamic working performance was then assessed by SIMPACK software. Results of the four dynamic indices for both straight and curve tracks were within the limits, which had verified the design rationality of the new rail-grinding car. Those dynamic indices are the lateral vibration acceleration, the vertical vibration acceleration, the axle transverse force, and the derailment coefficient.

In order to calculate analytically the contact status for rail grinding by abrasive belt with an axis deflection, as well as considering limitations of using Hertz contact theory for that, a numerical contact model (NCM) based on the local geometrical relationship between contact wheel and rail surface was developed. The effectiveness and accuracy of the proposed model have been validated by the corresponding finite element model (FEM) by comparing the contact boundary and contact stress distribution. Comparative cases at two typical grinding positions with different attitudes were involved, and the effects of applying axis deflection on contact behavior were investigated in detail. The results from NCM and FEM both agreed belt grinding with an axis deflection was able to enlarge the contact width of the belt and the total grinding force under the premise of ensuring required width of grinding trace on the rail. The model provides insights into understanding contact behavior under actual working conditions and gives a theoretical basis for future researches based on contact analysis.

：Rail grinding with abrasive belt essentially appears as the complex nonlinear contact interaction among contact wheel, abrasive belt and rail surface, the contact stresses calculation in which is the basis of modeling of material removal, grinding temperature and abrasive belt wear. However, the existing contact model for the concave contact wheel falls to consider the applicability of the Hertz theory and the effect of the "wheel" curvature matching. Based on the geometric matching between the radius curvature of concave wheel and that of rail profile, and also the influence of external contact pressure on rubber deformation of contact wheel, the macro contact of abrasive belt rail grinding is divided into three cases, including oval contact, double triangular contact and saddle contact. Then, this 3D contact problem is translated into 2D plane contact problem between the circular rigid body covered with thin elastic rubber layer and the rigid plane. Finally, the theoretical models for boundary curve and contact stress distribution are developed, and the finite element simulations are also implemented. Results show that almost identical contours of oval contact, double triangular contact and saddle contact can be obtained through the theoretical model and the simulation model, and the errors of main parameters are all within the allowable range of grinding condition for the rail grinding with abrasive belt, which verifies the validity of the proposed theoretical model. The proposed theoretical model has improved the existing model and laid a theoretical foundation for the modeling of grinding material removal for abrasive belt rail grinding using concave wheel.

The current research of abrasive belt grinding rail mainly focuses on the contact mechanism and structural design. Compared with the closed structure abrasive belt grinding, open-structured abrasive belt grinding has excellent performance in dynamic stability, consistency of grinding quality, extension of grinding mileage and improvement of working efficiency. However, in the contact structure design, the open-structured abrasive belt grinding rail using a profiling pressure grinding plate and the closed structure abrasive belt using the contact wheel are different, and the contact mechanisms of the two are different. In this paper, based on the conformal contact and Hertz theory, the contact mechanism of the pressure grinding plate, abrasive belt and rail is analyzed. Through finite element simulation and static pressure experiment, the contact behavior of pressure grinding plate, abrasive belt and rail under single concentrated force, uniform force and multiple concentrated force was studied, and the distribution characteristics of contact stress on rail surface were observed. The results show that under the same external load, there are three contact areas under the three loading modes. The outer contour of the middle contact area is rectangular, and the inner contour is elliptical. In the contact area at both ends, the stress is extremely small under a single concentrated force, the internal stress is drop-shaped under a uniform force, and the internal stress under multiple concentration forces is elliptical. Compared with the three, the maximum stress is the smallest and the stress distribution is more uniform under multiple concentrated forces. Therefore, the multiple concentrated forces is the best grinding pressure loading mode. The research provides support for the application of rail grinding with open-structured abrasive belt based on pressure grinding plate, such as contact mechanism and grinding pressure mode selection.