双剪统一弹塑性有限差分法在金属结构中的应用

Application of Twin Shear Unified Elastoplastic Finite Difference Method in Metallic Structures

双剪统一强度理论及其弹塑性有限差分方法引入到金属结构的数值模拟中,对金属结构强度及金属加工等问题的研究具有实际意义。简要介绍双剪统一强度理论和拉格朗日有限差分方法的理论基础,推导双剪统一弹塑性有限差分格式,并利用C++语言编写动态连接库文件载入FLAC中进行计算。分别计算分析厚壁圆筒受均匀内压和中心带孔铝板的拉伸两个问题并与有限元法的计算结果进行比较,通过两个算例的计算结果说明拉格朗日有限差分方法的计算精度与有限元软件差别不大,双剪统一弹塑性有限差分方法能够运用到金属结构的数值分析研究中来,并且双剪统一强度理论可以适用于抗剪强度与抗拉强度之比为0.500和0.667之间的金属材料,使其在金属结构数值分析中的应用范围更加广泛。

Twin shear unified strength theory is applied to the numerical simulation of metallic structures with the method of elastoplastic finite difference.This work has actual significance for the problem of metallic structures strength or processing research.Firstly,the twin shear unified strength theory and the method of Lagrangian finite difference are briefly introduced.Secondly,the finite difference formulation of twin shear failure criteria and flow rule is derived and the model is loaded into FLAC code with dynamic-link library file compiled by language of C＋＋.Finally,the cases of thick-walled cylinder under internal pressure and perforated plate in tension are calculated.The calculation results of analyses suggest that the precision of Lagrangian finite difference method and finite element method are similar.Twin shear unified strength theory can be applied to the metallic materials with a ratio of shear strength to tension strength between 0.5 and 0.667,so that it will have wide application in numerical simulation of metallic structures.