Nonlinear Analysis

Material Nonlinear

• Plasticity
  
• Nonlinear elasticity
• Large strain hyperelastic
• Large strain isotropic
• Thermo-elasticity
• Temperature dependence
• Creep
• Brittle material (concrete)
• Shape memory material (Nitinol)

Geometric Nonlinear

• Large displacements and rotations (updated Lagrangian)
• Follower forces
• Snap-through analysis
• Displacement control

Contact

• Gap
• Slide Line
• Surface-to-Surface
• All contact elements (gap, slide line, and surface-to-surface contact) support friction

A nonlinear static post-buckling analysis of a thin-walled square tube. The analysis involves large displacements and rotations with a nonlinear plastic material and surface contact. Note the secondary buckling that occurs after the outer surfaces near the fixed end contacts.

Nonlinear Composites

• Progressive Ply Failure Analysis for Nonlinear Static and Transient solutions (PPFA)*
• Helius:MCT Ply Failure integration*
• Adaptive Nonlinear Static and Transient Analysis
• Temperature dependent composites material properties

Tension Only

• Cable
• Shell Element
• Multiple loading conditions

Direct Nonlinear Solutions
(No Restarts Required)

• Nonlinear Buckling
• Nonlinear Prestress (static and dynamic response)
• Nonlinear Transient Response (Event Simulation)

This video demonstrates nonlinear transient press forming simulation of a thin metal sheet using NEi Explicit. The sheet is modeled with plate elements and uses a nonlinear plastic material property to account for plastic strain. The die (not shown) was setup as a solid rigid part. The contour shows the remaining plastic strain after the die is removed. This analysis is very useful in predicting the final shape of a stamped sheet metal part.

A nonlinear transient analysis of a rubber membrane. The analysis involves large displacements, rotations, and post-buckling behavior.

Automated Solutions Tools

• Adaptive (load increment and time step)
• Combined load-displacement control method
• Arc-length methods
• Stiffness updates for unloading
• Implicit Newmark-Beta time step integrator
• Automated Surface Contact Generation (ASCG™)
• Automated Edge Contact Generation (AECG™)
• Automated Impact Analysis (AIA™)

Global Matrix Output

• Linear stiffness matrix
• Tangent stiffness matrix
• Mass matrix

Direct Matrix Input Grid (DMIG) Support

• Stiffness matrix import and export
• Mass matrix import and export
• Damping matrix import and export
• Load vector import and export

Modal Reduction

• Static condensation
• Export reduced stiffness matrix using DMIG format

A nonlinear static analysis of a rivet being deformed to hold two plates together. One end of the rivet is held fixed while the other end is forced into compression with a force load. A nonlinear material is used to accurately model the material behavior and high strains involved. Surface contact with friction is used between all parts.

Full Analysis Compatibility

• Linear analysis model can be easily extended to nonlinear analysis
• All elements can be included
• Similar output formats
• User definable restart capability for nonlinear static analysis

Visualization in the Editor

• Maximum displacements, stresses, etc. can be tracked as a function of loading
• View results real-time as they change for each load increment or time step
• Change nonlinear parameters real-time
• Generate dynamic plots automatically during nonlinear analysis
• Generate x-y plots real-time and store as MS Excel Comma Separated Variable (.CSV) files
• Generate multiple plots with a single command
• Custom x-y plotting of results