The ABAQUS system includes ABAQUS/Standard, a general-purpose finite element program; ABAQUS/Explicit, an explicit dynamics finite element program; and the Visualization module, an interactive postprocessing program that provides displays and output lists from output database files written by ABAQUS/Standard and ABAQUS/Explicit.
This manual describes the theories used in ABAQUS. Many sections in this manual apply to both ABAQUS/Standard and ABAQUS/Explicit. Certain sections obviously apply only to either ABAQUS/Standard or ABAQUS/Explicit; for example, all sections in the chapter on procedures apply to ABAQUS/Standard, except the section discussing the explicit dynamic integration procedure, which applies to ABAQUS/Explicit. If it is not obvious to which program a section applies, it is clearly indicated.
ABAQUS/Standard includes three added-cost options. The ABAQUS/Aqua option includes features specifically designed for the analysis of beam-like structures installed underwater and subject to loading by water currents and wave action. The ABAQUS/Design option enables the user to parametrize input file quantities and write Python scripts to perform parametric studies. The ABAQUS/Foundation option offers more efficient access to the linear static and dynamic analysis functionality in ABAQUS/Standard. Certain aspects of the theory behind these options are described in this manual. The options are available only if the user's license includes them.
The objective of this manual is to define the theories used in ABAQUS that are generally not available in the standard textbooks on mechanics, structures, and finite elements but are well known to the engineer who uses ABAQUS. The manual is intended as a reference document that defines what is available in the code. Nevertheless, it is written in such a way that it can also be used as a tutorial document by a reader who needs to obtain some background in an unfamiliar area. The material is presented in a way that should make it accessible to any user with an engineering background. Some of the theories may be relatively unfamiliar to such a user; for example, few engineering curricula provide extensive background in plasticity, shell theory, finite deformations of solids, or the analysis of porous media. Yet ABAQUS contains capabilities for all of these models and many others. The manual is far from comprehensive in its coverage of such topics: in this sense it is only a reference volume. The user is strongly encouraged to pursue topics of interest through texts and papers. Chapter 7, “References,” at the end of this manual lists references that should provide a starting point for obtaining such information. (ABAQUS does not supply copies of papers that have appeared in publications other than those of ABAQUS. EPRI reports can be obtained from Research Reports Center (RRC), Box 50490, Palo Alto, CA 94303.)
Chapter 1, “Introduction and Basic Equations,” discusses the notation used in the manual, some basic concepts of kinematics and mechanics—such as rotations, stress, and equilibrium—as well as the basic equations of nonlinear finite element analysis. Chapter 2, “Procedures,” describes the various analysis procedures (nonlinear static stress analysis, dynamics, eigenvalue extraction, etc.) that are available in ABAQUS. Chapter 3, “Elements,” describes the element formulations. Chapter 4, “Mechanical Constitutive Theories,” describes the mechanical constitutive theories.
Chapter 5, “Interface Modeling,” discusses the most important aspects of the contact/interaction formulation in ABAQUS/Standard. Chapter 6, “Loading and Constraints,” describes the formulation of some of the more complicated load types and multi-point constraints.