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View new features for OptiStruct 2025.
Overview
OptiStruct is a proven, modern structural solver with comprehensive, accurate and scalable solutions for linear and nonlinear analyses across statics and dynamics, vibrations, acoustics, fatigue, heat transfer, and multiphysics disciplines.
Tutorials
Discover OptiStruct functionality with interactive tutorials.
User Guide
This manual provides detailed information regarding the features, functionality, and simulation methods available in OptiStruct.
Reference Guide
This manual provides a detailed list and usage information regarding input entries, output entries, and parameters available in OptiStruct.
Example Guide
The OptiStruct Example Guide is a collection of solved examples for various solution sequences and optimization types and provides you with examples of the real-world applications and capabilities of OptiStruct.
- Nonlinear Small Displacement Analysis
  This section presents nonlinear small displacement analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Nonlinear Large Displacement Analysis
  This section presents nonlinear large displacement analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
  - OS-E: 0100 Nonlinear Analysis of Cantilever Beam
    A cantilever beam undergoing large deflections is conducted and compared with 2D shell and 3D solids elements here, using OptiStruct.
  - OS-E: 0105 Nonlinear Analysis of Cantilever Beams with Follower Forces
    Three cantilever beams are analyzed.
  - OS-E: 0110 Elastic-Plastic Large Displacement Analysis
    Large displacement analysis of a dog-bone type tensile coupon with elastic-plastic material properties is demonstrated in this example.
  - OS-E: 0115 Finite Sliding Contact
    Nonlinear Analysis with finite sliding contact between rack and pinion gears.
  - OS-E: 0120 Nonlinear Static Analysis with Hyperelastic Material Model, under Compression Loading and Unloading
    Behavior of hyperelastic material during loading and unloading phases. Typical examples include rubber mounts, boot seals, and rubber keyboard domes.
  - OS-E: 0125 Diagnose Non-converged Solution using NLMON
    Modeled using solid and shell elements and when the solution is not converged, run diagnostics modeling errors using NLMON.
  - OS-E: 0130 Plate with Central Hole using NLOUT
    A uniform, homogeneous plate which is symmetric about horizontal axes in both geometry and loading, to find the maximum axial stress in the plate with a hole.
  - OS-E: 0135 Contacts and Pretensioning of Bolts
    Nonlinear Static analysis involving contacts and pretensed bolts is demonstrated.
  - OS-E: 0140 Pretension Analysis of Piston
    Convert an Abaqus model to OptiStruct using HyperMesh and SimLab.
  - OS-E: 0145 Nonlinear Analysis of Rack and Pinion using Restart
    This example problem is of a rack and pinion mechanism, and showcases the restart capability available in OptiStruct.
  - OS-E: 0150 Large Displacement Analysis of Chassis
    Demonstrates the use of 2D plate (shell) elements with large displacement analysis.
  - OS-E: 0155 Snap-Fit Analysis (CONSLI versus FINITE)
    Snap-fit is a combination of two components namely mating and base part which form a mechanical attachment between them by means of locators, locks and enhancements. Nonlinear Static Analysis with large displacement theory is used to solve this example.
  - OS-E: 0160 Nonlinear Static Analysis of Snap Fit Assembly Using Continuous Sliding
    Demonstrates the effect of continuous sliding in Nonlinear Static (large displacement) Analysis.
  - OS-E: 0165 Contact Smoothing With Two Concentric Rings
    Contact smoothing is useful to increase accuracy of the contact solution. An enforced displacement to push two concentric rings toward each other to engage the contact is used. The usage of NLOUT entry allows you to study the progression of SPC force over successive increments.
  - OS-E: 0170 Revolute Joint Using JOINTG and MOTNJG
    Demonstrate a revolute joint using JOINTG and MOTNJG. The JOINTG entry can be used for defining a variety of joints, including revolute, ball, universal, cardan, and so on. Motion on these joints can be applied using the MOTNJG entry.
  - OS-E: 0175 Continuum Shell Composites Using PCOMPLS
    The PCOMPLS entry can be used to define continuum shell composites using solid elements. Currently first order CHEXA and CPENTA solid elements are supported.
  - OS-E: 0180 3-Point Bending using RBODY
    Demonstrates RBODY which is used in this nonlinear large displacement implicit analysis involving contacts using OptiStruct.
  - OS-E: 0185 Rubber Ring: Crush and Slide Using Self-Contact
    Demonstrates self-contact which is used in this nonlinear large displacement implicit analysis involving hyperelastic material and contacts using OptiStruct.
  - OS-E: 0190 Large Displacement Subcase as Preload to Linear Subcases
    Preloaded or Prestressed Linear Analysis is any type of Structural Linear Analysis performed on a structure under prior loading.
  - OS-E: 0195 Compression of Helical Springs using Self-Contact
    This example explains how to use the self-contact to simulate the spring compression.
- Nonlinear Transient Analysis
  This section presents nonlinear transient analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Frequency Response Analysis
- Normal Modes Analysis
  This section presents normal modes analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Complex Eigenvalue Analysis
  This section presents complex eigenvalue analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Thermal and Heat Transfer Analysis
  This section presents thermal and heat transfer analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Analysis Techniques
  This section presents analysis technique examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Topology Optimization
- Size (Parameter) Optimization
- Free-shape Optimization
- Shape Optimization
  This section presents shape optimization example problems, solved using OptiStruct. Each example uses a problem description, execution procedures and results to demonstrate how OptiStruct is used in shape optimization.
- Topography Optimization
  The examples in this section demonstrate how topography optimization generates both bead reinforcements in stamped plate structures and rib reinforcements for solid structures.
- ESLM Optimization
  The examples in this section demonstrate how the Equivalent Static Load Method (ESLM) can be used for the optimization of flexible bodies in multibody systems.
- Multiphysics
  This section presents multiphysic examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Rotor Dynamics
- Response Spectrum
  This section presents response spectrum examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Nonlinear Explicit Analysis
  This section presents nonlinear explicit analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
- Piezoelectric Analysis
  This section presents piezoelectric analysis examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used.
Verification Problems
This manual presents solved verification models including NAFEMS problems.
Frequently Asked Questions
This section provides quick responses to typical and frequently asked questions regarding OptiStruct.

OS-E: 0145 Nonlinear Analysis of Rack and Pinion using Restart

This example problem is of a rack and pinion mechanism, and showcases the restart capability available in OptiStruct.

Model Files

Before you begin, copy the file(s) used in this example to your working directory.

Model Description

Nonlinear Quasi-Static (NLSTAT) subcase with Large Displacement (LGDISP) is used here to simulate the interaction between rack and pinion. Contact tracking is based on continuous sliding contact algorithm.

FE Model
Element Types: CHEXA

The linear material properties are:

MAT1
Young’s Modulus: 2.1E5 MPa
Poisson's Ratio: 0.3
Density: 7.85E-9

Results

The deformations are compared (Figure 2).