The Complementarity Method For Elastic Contact Problems Of Heavy-load Manipulator

The heavy-load manipulator is actually a kind of huge robot under the extreme load environment in industry.The high temperature and non-continuum load may cause the failure of the interface lubrication and the elasto-plastic deformation of the contact area in the shaft.These typical contact behaviors may result in huge contact stress,which will affect the performance,reliability,precision and service life of the manipulation.Therefore,the efficient and accurate analysis of the contact stress in the interface of shafts is very important for the optimization design and fatigue analysis of the heavy-load manipulator.The linear complementarity method for elastic contact problems based on the principle of virtual work is used in this paper,with its simplified theoretical derivation,clear concept and non-iterative solution procedure.The FEM program based on this method is realized to analyze the contact stress of the shafts of the manipulator,whose accuracy and effectiveness was demonstrated by comparing the numerical results of the FEM program with the analytic Hertz results.The non-convergence ray solution may occur when using Lemke algorithm to solve the elastic frictional contact problem with the linear complementarity method.In this paper, NCP function method is used to convert the integrated complementary conditions into nonlinear equations.When the available NCP function is selected,the satisfying result can be obtained,in accordance with the ABAQUS numerical results.Finally,the contact stress in the interface of shafts in the heavy-load manipulator was obtained from the FEM program and compared with results of ABAQUS numerical analysis. The results in this paper is helpful to the optimization design,reliability design and fatigue analysis of the heavy-load manipulator.