Page History

...

One of the important measure in race car design is torsional stiffness. To obtain that specification, a twist test must be performed on the chassis. Here is The figure below shows a simplified version of a race car chassis with a composite monocoque and two front suspension links. To simulate a twist test, the back of the monocoque will be fixed while coupling will be applied to the end of the two front suspensions. The .igs file for the geometry can be downloaded here: monocoque.IGS. 

The analytical calculation of the problem are explained in this PDF document.  These passages are taken from the isotropic analysis section of "Design, Analysis and Testing of a Formula SAE Carbon Fiber Monocoque Chassis" by Jingsi Wu, Owusu A. Agyeman Badu, and Yongcheng Tai.  

Geometry Specification

Image Added

One of the beauty of composite material is to customize the ply lay-ups to achieve optimum properties according to the needs. It is often the case where different ply lay-ups are used at different monocoque regions for their specific needs. This exercise has 4 different regions as shown in the diagram below:

Image Removed

above diagram. Details of the composite layup will be explained during the exercise.

Calculate the Torsional Stiffness

Ansys gives tangential displacement values for torsional displacement. Here are the equations to calculate torsional stiffness.What we will find using ANSYS is torsional displacement. From this, torsional stiffness can be calculated as follows:

Go to Step 1: Pre-Analysis & Start-Up

...