OptiStruct for Linear Analysis (3) Inertia Relief Analysis

1. Inertia Relief Analysis Setup

In this lesson we will cover a brief explanation of what inertia relief analysis is and the necessary information needed for setting up and running an inertia relief analysis in OptiStruct.  Watch the video below to learn more.

What is Inertia Relief?

Inertia Relief analysis allows the simulation of unconstrained structures. Typical applications include: an airplane in flight, suspension parts of a car, or a satellite in space.

With Inertia Relief, the applied loads are balanced by a set of translational and rotational accelerations. These accelerations provide body forces, distributed over the structure in such a way that the sum total of the applied forces on the structure is zero. This provides the steady-state stress and deformed shape in the structure as if it were freely accelerating due to the applied loads. 

Boundary conditions are applied only to restrain rigid body motion. Because the external loads are balanced by the accelerations, the reaction forces corresponding to these boundary conditions are zero.

Inertia Relief Analysis Setup

• PARAM

• SUPORT

• Mass/COG/MOI

Inertia Relief Analysis Workflow

2. Exercise - Satellite Inertia Relief Analysis

In this exercise we will start by loading a satellite model in HyperWorks. Next, we will set up inertia relief constraints and create four loading conditions – 3Gx, 3Gy, 2Gz, and 4.7G combined load.  Then, we will update the run options and parameters and define loadsteps before running the analysis in OptiStruct.  Finally, we will post-process the displacement and vonMises stress results for the four loadsteps in the HyperView client.

Watch the video below to view a demonstration of the exercise.  Then download the PDF and model files to do the exercise yourself!

 

Files:

• ex2a.pdf
• 2A.zip

 

Next: OptiStruct for Linear Analysis (4) Normal Modes Analysis