The Axisymmetic Rigid-Plastic Meshless Method And Its Application In Forming

There is a great number of large elastic-plastic deformation inengineering field such as plastic forming, structure collision. When simulatingthese process by Finite element method, we need to adopt theelement-remeshing technique to solve the problem that there is elementdistortion and gain the more accurate result. But the efficiency and precisionof computation will decrease.In this paper, RKPM meshless method, which has been developed andsprung up in recent years, is used to analyse the rigid-plastic upset problem.Because the meshless method only need node data and then the remeshing isavoided. Accordingly, it overcomes the drawback we have mentioned firstly.so this method is applicable to solve the large deformation problem and it hasthe merit of simple post-processing and high computing precision.In this paper, the basic principles of meshless method are introducedfirstly, including the approximation methods, weight function, domain ofinfluence, integration method, the handing of boundary condition et al, andseveral ordinary meshless methods are introduced;secondly, the variationprinciple of rigid-plastic meshless method is introduced, the formula ofaxisymmetric rigid-plastic RKPM method are deduced and the differentbetween meshless method and finite element method are analysed;Finally, theprogram of axisymmetric rigid-plastic meshless method is developed, and theprocedure of the upsetting is analyzed. By contrast to the simulated results ofDEFORM, it is known that the two results coincide with each other well,which certifies the feasibility and validity of this method. By using thecomputer program simulate the upsetting procedure of the cylinder, when itsratio of the height and diameter is 1.0 and the friction factor is form 0.05 to 0.5,give the quantitative relationship of the sample crowning in the upsettingexperiment, the friction factor of the contact surface, the deformation velocityand the temperature. This relationship can be used to estimate the frictionfactor of the contact surface. Finally, we have verified the feasibility of themeshless method by the upsetting experiment of different friction condition.