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1、【精品文档】如有侵权，请联系网站删除，仅供学习与交流VUMAT-中英文对照.精品文档.25.3.4VUMAT25.3.4VUMATUser subroutine to define material behavior.定义材料本构用户子程序Product: ABAQUS/ExplicitWarning: The use of this user subroutine generally requires considerable expertise. You are cautioned that the implementation of any realistic constitutive
2、model requires extensive development and testing. Initial testing on a single-element model with prescribed traction loading is strongly recommended.注意：用户子程序的使用通常需要一定的专长。用户需要知道执行任何实际的本构模型需要大量的试验数据。强烈建议用户对用户子程序进行在指定拉力作用下单个单元的验证测试。The component ordering of the symmetric and nonsymmetric tensors for th
3、e three-dimensional case using C3D8R elements is different from the ordering specified in “Three-dimensional solid element library,” Section 14.1.4, and the ordering used in ABAQUS/Standard.C3D8R单元三维轴对称及非轴对称张量成分顺序与“Three-dimensional solid element library,” Section 14.1.4及ABAQUS/Standard中指定的顺序不同。Refe
4、rences “User-defined mechanical material behavior,” Section 12.8.1 *USER MATERIALOverviewUser subroutine VUMAT: 用户子程序VUMAT is used to define the mechanical constitutive behavior of a material; 用来定义材料的力学本构关系 will be called for blocks of material calculation points for which the material is defined in
5、 a user subroutine (“Material data definition,” Section 9.1.2); 可以被用户子程序定义材料计算点调用 can use and update solution-dependent state variables; 可以使用和更新结果依赖状态变量 can use any field variables that are passed in; 可以使用传入的任何场变量 is described further in “User-defined mechanical material behavior,” Section 12.8.1; a
6、nd 在“User-defined mechanical material behavior,” Section 12.8.1中详细论述； cannot be used in an adiabatic analysis. 可以被用于绝热分析Component ordering in tensors 张量组成顺序The component ordering depends upon whether the tensor is symmetric or nonsymmetric.张量组成顺序取决于其是否为对称或非对称张量。Symmetric tensors 对称张量For symmetric te
7、nsors such as the stress and strain tensors, there are ndir+nshr components, and the component order is given as a natural permutation of the indices of the tensor. The direct components are first and then the indirect components, beginning with the 12-component. For example, a stress tensor contain
8、s ndir direct stress components and nshr shear stress components, which are passed in as 对于如同应力及应变张量等的对称张量，含有ndir+nshr分量，分量的序号按张量索引号的自然排序给出。首先是直接分量，然后是从12分量开始的间接分量。例如，包含ndir正应力分量及nshr的剪应力张量的应力张量被按照下面的顺序传入Component2-D Case3-D Case123456The shear strain components in user subroutine VUMAT are stored a
9、s tensor components and not as engineering components; this is different from user subroutine UMAT in ABAQUS/Standard, which uses engineering components. Nonsymmetric tensors 非对称张量For nonsymmetric tensors there are ndir+2*nshr components, and the component order is given as a natural permutation of
10、the indices of the tensor. The direct components are first and then the indirect components, beginning with the 12-component. For example, the deformation gradient is passed as 对于非对称张量含有ndir+2*nshr分量，分量的顺序按照张量索引号的自然排序给出。首先是直接分量，其次是从12分量开始的间接分量。例如，位移梯度按照下面的顺序传递Component2-D Case3-D Case123456789Initia
11、l calculations and checks 最初计算和检查In the data check phase of the analysis ABAQUS/Explicit calls user subroutine VUMAT with a set of fictitious strains and a totalTime and stepTime both equal to 0.0. This is done as a check on your constitutive relation and to calculate the equivalent initial material
12、 properties, based upon which the initial elastic wave speeds are computed.在ABAQUS/Explicit调用用户子程序VUMAT分析的数据检查阶段,小应变、总时间及时间步都为0。这作为对用户本构关系的一个检查，基于计算得到的初始材料波速来计算等效初始材料属性。Defining local orientations 定义局部方向All stresses, strains, stretches, and state variables are in the orientation of the local materia
13、l axes. These local material axes form a basis system in which stress and strain components are stored. This represents a corotational coordinate system in which the basis system rotates with the material. If a user-specified coordinate system (“Orientations,” Section 2.2.5) is used, it defines the
14、local material axes in the undeformed configuration.所有的应力、应变、延伸及状态变量均按局部材料轴的方向。这些局部材料轴形成一个应力与应变分量存储的基本系统。即这个基本系是随着材料联合转动的坐标系。如果使用用户指定坐标系，则它在无变形结构中定义局部材料轴。Special considerations for various element types不同单元类型的特殊考虑The use of user subroutine VUMAT requires special consideration for various element typ
15、es.用户子程序VUMAT的使用需要对不同的单元类型进行特殊的考虑。Shell and plane stress elements壳及平面应力单元You must define the stresses and internal state variables. In the case of shell or plane stress elements, you must define strainInc(*,3), the thickness strain increment. The internal energies can be defined if desired. If they are not defined, the energy balance provided by ABAQUS/Explicit will not be meaningful.用户必须定义应力和初始状态变量。在壳或平面应力单元的情况下，用户必须定义应变包括（*,3），厚度应变增量。如果需要的话还需要定义初始能量。如果没有定义，那么ABAQUS/Explicit提供的能量平衡将没有意义。Shell elements壳单元When VUMAT is u
