采用非连续变形分析对空气冲击湿砂造型过程的数值模拟  

NUMERICAL SIMULATION OF PNEUMATIC MOULDING PROCESS BY DISCONTINUOUS DEFORMATION ANALYSIS

作　　者：姚振汉[1] 张锐[1] 

机构地区：[1]清华大学工程力学系,北京100084

出　　处：《工程力学》2002年第5期24-28,共5页Engineering Mechanics

摘　　要：空气冲击湿砂造型过程有着本身的特点：快速冲击，离散的材料体系，材料非线性和几何大变形并存，是一个非常复杂的力学过程。本文首次使用非连续变形分析(DDA)的方法建立了粘弹性本构非连续块体模型模拟松散型砂体系，对松散型砂在空气冲击作用下的密实过程进行了数值模拟。通过与相应的实验数据以及有限元方法的计算结果进行比较，本文得出以下结论：非连续变形分析方法可以较好地解决湿砂造型空气冲击紧实过程的数值模拟问题，其应力时间曲线与实测曲线趋势基本相同，相对于有限元方法的计算结果来说，DDA的计算应力值与实测应力值的偏差比较小；使用非连续变形分析进行松散型砂应力场的数值模拟比有限元方法更接近真实情况。The pneumatic moulding is a very complex mechanical process with the features of fast impact, discrete materials, combined geometrical and material nonlinearity. A discrete viscoelastic model for the simulation of incompact molding sand is presented, based on the discrete deformation analysis (DDA) method, and the densification process of the molding sand under air impact is simulated in this paper. The results obtained, in comparison with the corresponding experimental data and the computational results by finite element method, show that the DDA method is applicable for the numerical simulation of the densification process of the molding sand in pneumatic moulding process: The variation tendency of the stress-time curves obtained by DDA is basically consistent with the experimental data, and its error is less than that obtained by FEM, the simulation by DDA is much closer to the reality.

关 键 词：数值模拟 湿砂造型 空气冲击造型 非连续变形分析 

分 类 号：TB321[一般工业技术—材料科学与工程]