实体壳单元在板料成形及回弹模拟中的应用

开发了基于实体壳单元的动力显式及隐式程序,模拟了板料成形及回弹过程.该实体壳单元具备如下特性：考虑厚度变化的双面接触判断精确模拟了板材厚向挤压变形;采用厚向多点积分方式求解内力,精确地描述了弯曲效应,回弹预测更为准确;面内减缩积分有效抑制了剪切闭锁与体积闭锁;黏性阻尼沙漏控制算法克服了面内减缩积分激活的零能模式;采用改进的平面应力本构模型且结合希尔二次异性屈服准则,使得实体壳单元同时获得实体单元和壳单元的特性,非常适合于非线性大变形有限元分析.给出了几个算例验证单元的有效性及程序的稳健性,并与实验结果及相关文献中的模拟结果进行了比较.

Application of solid-shell element to forming of sheet metal and simulation of springback

A new finite element solver based on the solid-shell element dynamic explicit algorithm and implicit algorithm were developed for sheet metal forming simulation and springback prediction.The solid-shell element has several remarkable characteristics as follows: double sided contact analysis considering thickness variation describes the extrusion deformation in the thickness direction more accurately;the thickness-direction multiple-point integration approach describes the bending effects more precisely and therefore the springback prediction is more accurate;the in-plane reduced integration(RI) inhibits the transverse shear locking and volume locking phenomena efficiently;the viscous damping hourglass control algorithm eliminates the spurious deformation modes activated by the in-plane RI;the improved plane-stress constitutive model combining with Hill′s quadratic anisotropic yield criterion makes the solid-shell element has both solid-like and shell-like behaviors to simulate large nonlinear deformation.To verify the effectiveness of the solid-shell element and the robustness of the solver,several numerical examples were given and compared with experiments and simulation results from related literatures.