率相关晶体塑性在有限元应用中的关键技术

Key problems for rate-dependent crystal plasticity applied in finite element simulation

率相关晶体塑性在有限元应用中存在数值求解稳定性、精度和效率不能兼顾的问题,这是由于其数值化过程中的诸多关键技术相互的制约所致。文章讨论了这些关键技术,指出了建模采用的变形构形和控制方程的主未知量对求解计算的影响,研究了本构计算的隐式和显式算法及数值技巧,并分析了有限元计算过程对本构求解的影响。基于对这些关键技术的研究及对其处理方法的探讨,简要给出了率相关晶体塑性隐式和显式模型及求解算法示例。圆棒料镦粗和杯形件拉深过程模拟研究表明,这些模型和算法能够较好地兼顾计算的稳定性、精度和效率,而且其结果也表明,文章对这些关键技术问题的处理是合理可行的。

Some problems for applying rate-dependent crystal plasticity into finite-element （FE） simulation are that computational stability, accuracy and efficiency can not be considered simultaneously in the constitutive equation＇s solution. This is constrained by several key problems lying in the numeralization of the model. These key problems are discussed in the paper. The influence of deformation configurations and main unknowns in controlling equation adopted in the model are pointed out. Implicit and explicit algorithm as well as some numerical techniques for the solution of constitutive equation are investigated. Additionally, the influence of the calculations of finite element method （FEM） on the solution of constitutive equation is analysis. Based on these studies and discusses, an implicit and an explicit crystal plasticity models as well as corresponding algorithms are given briefly for the examples. Round bar upset and cup drawing process are simulated based on given models, which indicates that computational stability, accuracy and efficiency are achieved simultaneously. These results prove that the handling approaches on these key problems in the paper is suitable and feasible.