2003, ABAQUS软件公司北京办事处.
ABAQUS/Standard 基础教程
A1.4
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
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ABAQUS/Standard 基础教程
A1.11
Elements in ABAQUS
• Element naming conventions: examples 单元命名约定
B21: Beam, 2-D, 1st-order interpolation S8RT: Shell, 8-node, Reduced integration, Temperature
• Contact 接触
• Incompressible Materials 不可压缩材料 • Mesh Generation 网格生成
• Solid Element Selection Summary
2003, ABAQUS软件公司北京代表处.
ABAQUS/Standard 基础教程
Elements in ABAQUS
A1.8
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 degrees of freedom are: • Displacements 位移
• Rotations 转角
• Temperature 温度 • Electrical potential 电势
2003, ABAQUS软件公司北京代表处.
ABAQUS/Standard 基础教程
ABAQUS/Standard 基础教程
Appendix 1
Element Selection Criteria
2003, ABAQUS软件公司北京办事处.
ABAQUS/Standard 基础教程
A1.2
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
• 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 same general element selection guidelines apply to both programs.
• The distance between supports or point loads
• The distance between gross changes in cross section • The wavelength of the highest vibration mode
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– 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
• Number of nodes 节点数
• Degrees of freedom 自由度数 • Formulation 公式 • Integration 积分
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ABAQUS/Standard 基础教程
A1.5
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.
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ABAQUS/Standard 基础教程
A1.10
Elements in ABAQUS
• Full integration: 完全积分
Full integration Reduced integration
• The minimum integration order required for exact integration of the strain energy for an undistorted element with linear material properties.
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ABAQUS/Standard 基础教程
A1.9
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.
• Reduced integration: 简缩积分 • The integration rule that is one order less than the full integration rule.
Firstorder interpolation
Secondorder interpolation
– 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.
2003, ABAQUS软件公司北京代表处.
ABAQUS/Standard 基础教程
Structural Elements (Shells and Beams) vs. Continuum Elements
2003, ABAQUS软件公司北京办事处.
ABAQUS/Standard 基础教程
ห้องสมุดไป่ตู้
A1.14
–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
special-purpose elements like springs, dashpots, and masses
truss elements
2003, ABAQUS软件公司北京代表处.
ABAQUS/Standard 基础教程
A1.6
Elements in ABAQUS
• Number of nodes 节点数(interpolation)
DC1D2E: Diffusion (heat transfer), Continuum, 1-D, 2-node, Electrical
2003, ABAQUS软件公司北京代表处.
ABAQUS/Standard 基础教程
A1.12