topic Re: Frame Analysis Errors in Inventor Forum

Frame Analysis Errors

ayanF4AT5 — Tue, 29 Mar 2022 13:10:22 GMT

I am trying to do frame analysis on a simple trailer. Once I select the 'Simulate' command I get two types of errors;

1. Torsional Section Modulus is zero

2. Unsupported frame member(s) were found...

As for the first error, I did some research and found that the workaround is to edit the Wz in the 'Beam Properties' dialogue box to a value of around 100 but I couldn't find anything on the second error.

Please help.

Re: Frame Analysis Errors

ayanF4AT5 — Tue, 29 Mar 2022 13:12:36 GMT

Here is a snap

Re: Frame Analysis Errors

JDMather — Tue, 29 Mar 2022 15:07:51 GMT

@ayanF4AT5 wrote:

Wz in the 'Beam Properties' dialogue box to a value of around 100

I wouldn’t just pull a number out of thin air.

Most likely both errors are resulting from the same Properties issue.

Can you Attach your assembly here (or at least one of the components with missing property)?

Oh wait a minute. Looks like you have a bent pipe - that is not supported with Beam Elements. You will have to replace (only for the purpose of Frame Analysis) with unbent pipes).

Re: Frame Analysis Errors

ayanF4AT5 — Wed, 30 Mar 2022 06:04:37 GMT

Thank you JD for your prompt reply.

I did replace the bent pipes with unbent pipes. There is still one error showing; Torsional section Modulus is Zero.

How do I fix this please?

Re: Frame Analysis Errors

JDMather — Wed, 30 Mar 2022 12:43:58 GMT

You did not Attach your assembly or a simple mock-up assembly which created extra work for me.

I had to do this work to find the issue.

Whoever created the original iPart configurations did not specify all of the Properties.

Therefore you need to calculate the Section Modulus for the 50x50x4 and the 25x25x2 and enter these into the Wz Beam Properties.

>>Area Moment of Inertia Section Properties: Rectangle Tube Calculator (engineersedge.com)<<

(Be sure to change the units to mm and enter the inside dimensions first.)

This is what I expected you to Attach - a simple assembly of these two components (at a minimum) to save me time (or the entire assembly).

Re: Frame Analysis Errors

ayanF4AT5 — Wed, 30 Mar 2022 13:18:20 GMT

Sorry about that JD, I used the calculator to get the Section Modulus as 1307.62667 and 10461.01333 units cubed respectively and inserted them in their Beam Properties. Attached is the file.

Thank you, I've learnt a lot.