Wheel-rail Contact Analysis Of Low-speed Heavy-duty Engineering Machinery

Construction machinery,as an important part of China’s machinery industry,play an important role in transportation,urban construction,farmland water conservancy and other fields.With the improvement of technology and the gradual increase of large-scale projects,construction machinery has also developed towards large-scale.Due to high load and frequent operation,large-scale construction machineries are designed by wheel-rail type.The wheel-rail contact state is the key to determine the structural supporting capacity.The structural contact characteristics belong to low-speed and heavy-duty conditions.The large-scale construction machinery makes the weight of the whole machine increase,therefore the dynamic load during working becomes larger and the whole machine shakes more severe,which puts high requirements on the strength,load bearing capacity and service life of the engineering machinery track and wheel.In this thesis the low-speed heavy-duty construction machinery was defined according to the wheel pressure value and the vehicle running speed.The virtual prototype model of gantry crane as a typical low-speed heavy-duty construction machinery was established by ADAMS.According to the working cycle process of the gantry crane under normal working conditions,the dynamics simulation analysis was carried out to obtain the motion characteristics and dynamic parameters such as the speed,acceleration and wheel-rail contact force of the gantry crane,and find the working state that produces the maximum wheel pressure value,which provided data support for the finite element analysis and optimization of the rail contact structure.The elastic contact analysis of the running wheel and the track was carried out by using the Hertz contact theory and the finite element elastic contact analysis method respectively.The method of finite element elastic contact analysis was more consistent with the actual contact state.The finite element elastoplastic contact analysis of the running wheel and the track was compared with the results of the elastic contact analysis.The results showed that the maximum stress in the wheel-rail structural had reached the material yield limit,and the elastic-plastic wheel-rail material has better bearing capacity.The basic analysis of the rimless wheel-track structure was compared with that for the structure of the double rim wheel.The contact area had a small stress magnitude and the structure had good stability.Sensitivity analysis of wheel-rail contact area parameters was carried out based on ANSYS PDS module to obtain and optimize the parameters which had the greatest impact on the contact analysis,which provide a reference for obtaining effective results of the contact analysis.Finally,based on the APDL parametric language of ANSYS,the structural parameters of the two-wheel rail structure were optimized and the material analysis selection for the frameless wheel-rail structure,the results before and after the optimization were compared to verify the rationality of the optimization.At present,there are few researches on the contact analysis of the wheel-rail structure of large engineering machinery.The contact structure of the low-speed heavy-duty engineering machinery wheel-rail structure was analyzed,and an optimization method was proposed to improve the analysis of the wheel-rail contact area,which had great significance for obtaining effective results of contact analysis.The improvement of wheel-rail structure can reduce the damage caused by contact to a certain extent.The works in this thesis provide reference and basis for the design and development of engineering machinery wheel-rail structure,and lay the foundation for developing engineering machinery technology.