Element Selection Criteria Appendix 1 内容提要 Elements in ABAQUS  Structural Elements (Shells and Beams) vs. Continuum Elements  Modeling Bending Using Continuum Elements 用实体单元模拟弯曲 Stress Concentrations 应力集中 Contact 接触 Incompressible Materials 不可压缩材料 Mesh Generation 网格生成 Solid Element Selection Summary  Elements in ABAQUS Elements in ABAQUS ABAQUS单元库中提供广泛的单元类型，适应不同的结构和几何特征The wide range of elements in the ABAQUS element library provides flexibility in modeling different geometries and structures.  Each element can be characterized by considering the following:单元特性： Family 单元类型 Number of nodes 节点数 Degrees of freedom 自由度数 Formulation 公式 Integration 积分  Elements in ABAQUS 单元类型（Family）  A family of finite elements is the broadest category used to classify elements.  同类型单元有很多相同的基本特。Elements in the same family share many basic features. 同种类单元又有很多变化：There are many variations within a family.  Elements in ABAQUS Number of nodes节点数(interpolation) An element’s number of nodes determines how the nodal degrees of freedom will be interpolated over the domain of the element. ABAQUS includes elements with both first- and second-order interpolation. 插值函数阶数可以为一次或者两次 Elements in ABAQUS 自由度数目Degrees of freedom The primary variables that exist at the nodes of an element are the degrees of freedom in the finite element analysis.  Examples of degrees of freedom are: Displacements 位移 Rotations 转角 Temperature 温度 Electrical potential 电势  Elements in ABAQUS 公式Formulation The mathematical formulation used to describe the behavior of an element is another broad category that is used to classify elements.  Examples of different element formulations:  Plane strain 平面应变 Plane stress 平面应力 Hybrid elements 杂交单元 Incompatible-mode elements 非协调元 Small-strain shells 小应变壳元 Finite-strain shells 有限应变壳元 Thick shells 后壳 Thin shells 薄壳 Elements in ABAQUS 积分Integration 单元的刚度和质量在单元内的采样点进行数值计算，这些采样点叫做“积分点” The stiffness and mass of an element are calculated numerically at sampling points called “integration points” within the element.  数值积分的算法影响单元的行为The numerical algorithm used to integrate these variables influences how an element behaves. ABAQUS包括完全积分和减缩积分。ABAQUS includes elements with both “full” and “reduced” integration. Elements in ABAQUS Full integration:完全积分 The minimum integration order required for exact integration of the strain energy for an undistorted element with linear material properties. Reduced integration:简缩积分 The integration rule that is one order less than the full integration rule. Elements in ABAQUS Element naming conventions: examples 单元命名约定 Elements in ABAQUS ABAQUS/Standard 和 ABAQUS/Explicit单元库的对比  Both programs have essentially the same element families: continuum, shell, beam, etc. ABAQUS/Standard includes elements for many analysis types in addition to stress analysis: 热传导, 固化soils consolidation, 声场acoustics, etc. Acoustic elements are also available in ABAQUS/Explicit. ABAQUS/Standard includes many more variations within each element family. ABAQUS/Explicit 包括的单元绝大多数都为一次单元。 例外: 二次▲单元和四面体单元 and 二次 beam elements Many of the s
ABAQUS单元选择.ppt