Torsional Constant of Cross Section

[mark1550]

I am attempting to calculate the torsional constant (area polar moment of inertia and warping constant) for an irregular cross section. I have the cross section image in DXF format. I read about Matlab programming that can calculate the polar moment of inertia by thresholding the picture and integrating the pixels. I can also construct a CAD file and I have access to Autodesk Inventor although I think at best this will provide the polar moment of inertia. I tried downloading the demo version of ShapeDesigner which does provide the actual torsional constant and warping function but the demo version doesn't allow any functionality. Any tips/thoughts on software or other routes that I might be able to use would be greatly appreciated.

Thanks!!!!

 

[john1999]

Hi mark1550,
I have the same problem as you computing J and CW. I contact support at mechatools.com for the ShapeDesigner Software. I send them the dxf file. The Demo version of shapedeigner is limetd to 12 points and 2 shapes and the DXF conversion not allowed in the demo version.

I purshased the ShapeDesigner V6.4 and really it works reslly good, So I resolved my problem

I hope this helps you

John

 

[GregLocock]

Be very careful. The torsional constant of an irregular section is not the same as the polar moment of inertia.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[JStephen]

Perhaps numerical integration via spreadsheet.