The problem of FEA analysis with P-Adaptive method 2

[cchngtn]

Dear respected Engineer,

I have found something strange about the P-method in cosmoswork professional. ( but may be I have wrong setting)

I found that when I increase the P-Adaptive method,
the polynomial I use 3, then 4, loop 3.

the maximum stress in analysis become higher and higher.

Why this happend?

 

[johnhors]

Have you got a sharp corner ?

 

[Kwan]

Sure sounds like a singularity to me. Perhaps a corner or some ugly elements?

 

[cchngtn]

Yes, that is true that the higher stress is at the corner element, but why this happend?

Is it I need to redesign the corner?

 

[johnhors]

You have to replace the corner with a fillet radius.

 

[EricZhao]

You have two choice to deal with sharp inner corner.

1) if you are confident that the corner is not the point of interest, just ignore it. the stress singularity is just a numerical issue.

2) if the corner is indeed your point of interest. model it with a fillet. Pure sharp corner doesn't exist in the real world.

 

[cchngtn]

Thanks. I change the design to fillet. But there is still some point have the higher and higher stress concentration.
why?

May be I should ommit the point?

 

[cchngtn]

For the weldment for the hollow beam to other hollow beam,
I found that I cant doing the fillet corner. The beam I definte in flat corner to represent the weldment, but the critical point concentrate at the flat corner. That is why I say the stress become higher and higher.

 

[mloew]

It sounds indeed like a singularity. You either need to refine the model in that area to realistically represent the geometry you are trying to study if it is an area of interest, or ignore the results in that area. Some good information on P-Method can be found in the FAQ P-Elements (faq828-810).

Best regards,

Matthew Ian Loew


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