Robot 2015 - torsional constant

[Anonymous]

see below

[Anonymous]

Hi I am trying to input a section into the robot 2015 similar to what I have done in previous 2012. The problem is it appears the torsional constant Ixx is wrong. I think this should be much bigger. The Iy and Iz values are correct as is the profile size.  Is this another error or am I doing something wrong. Please advise. See screen captures below.

Thanks

Daniel

[Artur.Kosakowski]

Calculations of Ix for thin walled section defined as solids may be inaccurate. Try to define it in the thin walled mode of the Section builder and then calculate IX. 

See message 4 from http://forums.autodesk.com/t5/Robot-Structural-Analysis/Custom-sections/m-p/3331345

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[Anonymous]

Artur,

How come it did it in 2012? Can we get it to do it in 2015 with an update?

I have read the message 4 but I am unsure how to do this - can you show me in screen captures step by step. Sorry about still relatively new and only way I was taught was to input profile through section difination.

Will the profile still look the same in the model?

Thanks

Daniel

[Artur.Kosakowski]

The Robot version is irrelevant.

After you calculated and saved your section defined as above in the user database:

1. Start new section definition in the Section Builder using the thin walled mode

2. Define the shape of a section

3. Calculate it and note Ix value

4. Replace the original IX with the new one in the user section database using the Section Database browser (Tools > Section Database)

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[Anonymous]

Hi Artur,

Just trying to import another section. It appears all values are not calculated when reuning calculation. Can you please explain why? See below 

[Rafal.Gaweda]

As fas as I can see the section has two separate parts - not possible for such section to calculate these values

[Anonymous]

Ok is there no way this can be calculated when separate? What if i use line between parts