Introduction Chapter One

Training Manual September 30, 2001 Inventory # Introduction Welcome! Welcome to the Advanced Structural Nonlinearities Training Course! This training course covers the wide range of constitutive models available in ANSYS, including advanced plasticity, viscoplasticity/creep, and hyperelasticity. Appropriate element selection, geometric instability, and element birth-and-death will be discussed as well. It is intended for ANSYS users who are already familiar with basic procedures for performing nonlinear static analyses using ANSYS (topics covered in the Basic Structural Nonlinearities class).

Training Manual September 30, 2001 Inventory # Introduction Welcome! This is the last in a series of three training courses on ANSYS nonlinearities: –Basic Structural Nonlinearities (2 days) –Advanced Contact and Bolt Pretension (1 day) –Advanced Structural Nonlinearities (2 days)

Training Manual September 30, 2001 Inventory # Introduction Course Objectives The topics covered in this Advanced Nonlinearities seminar can be classified into the following areas: Element Technology Metal Inelasticity Rubber Elasticity Geotechnical Materials Geometric Instability Element Birth & Death Rate-independent Behavior 1 Rate-dependent Behavior 2 Rate-independent Behavior 3 Rate-dependent Behavior 4 Linear Buckling Nonlinear Buckling Concrete Granular Materials 1 Plasticity models covered in this class do not include BISO, MISO, BKIN, KINH/MKIN since these have been addressed in the Basic Structural Nonlinearities Course 2 Includes creep (implicit and explicit CREEP) and viscoplasticity (RATE & ANAND) models. 3 i.e., Hyperelasticity 4 Although it is under the categorization of ‘Rubber elasticity,’ glass viscoelasticity model is also addressed in this section

Training Manual September 30, 2001 Inventory # Introduction Course Objectives Much of this seminar will focus on the 18x family of elements, due to their complete wealth of nonlinear features: –BEAM188/189 can have multi-material cross-section. SHELL181 supports composite definition. –HILL (anisotropic Hill potential) can be used with any plasticity model (including CREEP, RATE). –CHAB (Chaboche nonlinear kinematic hardening) can be combined with any isotropic hardening. –Although some cells above are blank, this is usually because item is not applicable to element. –All 18x elements support USERMAT user-defined material as well as USERCREEP user-defined implicit creep law. Elements support USERHYPER user-defined hyperelasticity model. User-programmable features will not be covered in this seminar. Please refer to ANSYS Guide to User-Programmable Features for details.

Training Manual September 30, 2001 Inventory # Introduction Course Objectives This class will cover ANSYS usage in these nonlinear topics. –When applicable, general information on material behavior, testing, and curve-fitting procedures will be discussed. Please keep in mind that this is not a material science course. It is assumed that the reader will be adequately familiar with the material behavior to make good engineering judgements. –This class will focus on issues pertinent to procedural aspects of usage of the material laws in ANSYS. –When possible, references for further reading will be presented. –Material testing should be done by those familiar with these types of procedures.

Training Manual September 30, 2001 Inventory # Introduction Course Material The Training Manual you have is an exact copy of the slides. Workshop descriptions and instructions are included in the Workshop Supplement. Copies of the workshop files are available (upon request) through your instructor.

Training Manual September 30, 2001 Inventory # Introduction Topics Covered 2. Element Technology 3. Advanced Rate-Independent Plasticity 4. Creep 5. Rate-Dependent Plasticity 6. Hyperelasticity 7. Viscoelasticity 8. Drucker-Prager/Concrete 9. Geometric Instability: Buckling 10. Element Birth and Death

Material Input Chapter One, Appendix A

Training Manual September 30, 2001 Inventory # Introduction Material Input Before beginning discussion on the Advanced Nonlinearities topics, the material input procedure will be covered. Nonlinear constitutive models can be input via commands or in the Materials GUI. –Commands take the following form: MP command defines linear material properties, if needed. TB command selects the nonlinear constitutive model TBTEMP defines temperature for temperature-dependency TBDATA defines the material parameters –(For MISO, KINH materials, TBPT is used instead) TBTEMP and TBDATA can be repeated for each temperature –GUI method of input uses the Materials GUI (explained next)

Training Manual September 30, 2001 Inventory # Introduction Materials GUI All structural material properties, linear and/or nonlinear, are conveniently defined through the Materials GUI –Main Menu > Preprocessor > Material Props > Material Models... Currently Defined Materials Available Constitutive Models

Training Manual September 30, 2001 Inventory # Introduction Materials GUI Structural Constitutive Models are organized into categories for easier selection:

Training Manual September 30, 2001 Inventory # If required, linear properties can be defined first through the Materials GUI: –Structural > Linear > Elastic > Isotropic Introduction Materials GUI

Training Manual September 30, 2001 Inventory # Introduction Materials GUI Note that if you may select a nonlinear constitutive model prior to defining the linear material data (EX, PRXY, etc.). If this nonlinear material requires linear material data, the Materials GUI will provide a warning: Then, the appropriate dialog box will appear. You will need to enter these linear material properties prior to providing input of nonlinear properties. Through this manner, the Materials GUI ensures proper and consistent material definition.

Training Manual September 30, 2001 Inventory # Introduction Materials GUI Other properties such as thermal expansion coefficient and density can also be defined, as needed.

Training Manual September 30, 2001 Inventory # Introduction Materials GUI Most materials can be temperature-dependent. The Materials GUI provides a dynamic spreadsheet where temperature- dependent constants can easily be added or deleted. –Data points are dynamically input (if applicable) –Some materials allow plotting of temperature-dependent data.

Training Manual September 30, 2001 Inventory # Introduction Materials GUI In the Materials GUI, new materials can be defined easily by specifying a different Material ID.

Training Manual September 30, 2001 Inventory # Introduction Materials GUI Materials may also be conveniently copied or deleted in the Materials GUI.