金属体积成形过程的无网格RPIM方法分析  

Numerical Simulation of Bulk Forming Processes by Radial Point Interpolation Method(RPIM)

作　　者：郑刚[1] 伍素珍[1] 李光耀[1] 崔向阳[1] 

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2010年第10期41-46,共6页Journal of Hunan University:Natural Sciences

基　　金：国际合作资助项目(2008DFB50020);教育部博士点新教师基金资助项目(2009016112007);现代车身设计制造国家重点实验室基金资助项目(70870006)

摘　　要：建立了基于无网格径向点插值RPIM法的二维体积成形动态显式计算模型.采用具有Delta函数性质的RPIM形函数构造位移域,因此可以很方便地施加本质边界条件.基于防御节点法给出了二维接触碰撞问题的接触力计算方法,避免罚函数法罚因子选择问题,以及拉格朗日乘子法不适合显式算法的问题.采用完全拉格朗日格式和弹塑性本构关系解决金属体积成形过程所涉及的几何非线性和材料非线性问题,并通过将工件变形分解为偏量部分和体积部分,有效消除金属体积成形中的体积自锁现象.数值算例表明,该算法可方便准确处理大变形畸变问题,是模拟金属体积成形过程的一种有效方法.The total Lagrangian formulation and implementation of radial point interpolation method（RPIM） was presented for the simulation of 2D bulk forming processes.In the present method,the displacement field function was approximated by using RPIM shape functions possessing Kronecker delta function property,which can facilitates the enforcement of essential boundary conditions.A simple contact searching algorithm was used to compute the contact force between the tools and the workpiece in the metal forming analysis and to solve the problems of the penalty method and Lagrangian multiplier method.In order to remedy the volumetric locking,the internal nodal forces of the workpiece were split into deviatoric part and volumetric part.The geometrical nonlinearities and material nonlinearities for the dynamic solution were treated by using the total Lagrangian description and an elastic-plastic constitutive law.In order to remedy the volumetric locking,the workpiece was deformed into two parts,deviatoric part and volumetric part.The numerical examples show that RPIM is more efficient in dealing with large deformation problems such as bulk forming with severe distortion.

关 键 词：金属体积成形 径向点插值法 接触 体积自锁 

分 类 号：TG301[金属学及工艺—金属压力加工]