基于宏观三角形分区平板壳单元的非线性有限元分析

针对剪切闭锁效应,本文研究了一种基于假设自然应变方法的宏观三角形分区平板壳单元。利用通用有限元软件ABAQUS所提供的用户自定义单元(UEL)和用户自定义材料(UMAT)子程序,本文将宏观三角形分区平板壳单元和基于损伤能释放率的混凝土弹塑性损伤本构模型成功嵌入了ABAQUS的主分析模块。经典试验McNeice双向混凝土板的数值模拟结果表明:宏观三角形分区平板壳单元对于描述板壳结构的非线性损伤行为是行之有效的。

Nonlinear finite element analysis based on macro triangular partition shell element

Due to the intractable shear locking effect,up to now most triangular shell elements are still denied in the practical analysis of engineering structures despite its comparative topological advantage.Based on the assumed natural strain(ANS) theory,this paper has studied a novel macro triangular partition shell element.With the introduction of a virtual node inside a normal three-node triangular mesh,a macro triangular partition shell element is formed with three individual sub-triangular domains.The strain and stress vectors of each individual domain as well as its corresponding stiffness matrix are specially calculated at certain sampling locations.After condensing out the virtual node,a macro triangular partition shell element still utilizes the same mesh discretization as a normal three-node triangular element.In virtue of the user subroutines UEL(user defined element) and UMAT(user defined material) integrated into engineering general-purpose simulation tool,ABAQUS,a successful nonlinear analysis has been obtained with the combination of macro triangular partition shell element and damage energy release rate-based elastoplastic damage constitutive model for concrete.A classical experiment,two-way McNeice concrete slab,has been presented to illustrate the efficacy of macro triangular partition shell element in describing nonlinear damage conditions of plate and shell structures.