Stress analysis with different materials produces same results problem

[Oli_Young]

Hi - can someone help? Noob question: I am trying to compare the results of two stress analyses - moments on steel and plastic levers, but the results seem to be the same. (Please see attached file) What might I be doing wrong?

[TheCADWhisperer]

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

Your image does not show the stress values? (Or displacement values.)

[Oli_Young]

Thanks for the reply. I thought the graph showing a factor 8 was the result of the test - and in both instances it is the same? I have enclosed the f3d file as well in the hope that you can help me understand, thanks.

[dsouzasujay]

Hi @Oli_Young 

As per Hooke’s law, Stress is proportional to Strain.

Stress=Load/Area

Strain=Change in Length/Original Length

So, Stress does not depend upon “Type” of material . Stress depends on the area on which force is acting.
If two objects of the same dimensions are subjected to identical loads(In your case Load case1 and Load case2 has same loads), then the stresses in the two objects will be identical.

[Oli_Young]

I think I have found the issue, and now I get a comparison that reflects the different reactions of a different material. 

[TheCADWhisperer]

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@Oli_Young wrote:

 I thought the graph showing a factor 8 was the result of the test - and in both instances it is the same?

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Actually - it is not showing that both are the same.

It is showing that both are 8+ that is, both are SF greater than 8.

You can change the SF legend to get actual values, but greater than 8 we probably don't care.

We generally only care about SF when it starts to approach 1 (linear elastic limit).

https://www.youtube.com/playlist?list=PLp5izJt_zvN0KUccGh5OrgbNTZ_c4vYxs