Linear Buckling and shell91

[Kottier]

Hi, I'm doing an linear buckling analysis on a composite turbine blade.
Now the certification organisation states that the use of the layered shell91 element, does not result in reliable values.
They advise the use of shell181 in order to obtain reliable results.

Now am I aware of the need to use surf154 element in combination with shell91 for good results, but only when a pressure load is applied and I'm using a nodel force as loading.

Can anybody advise

 

[Drej]

> Now the certification organisation states that the use of the layered shell91 element, does not result in reliable values.

Why?

> They advise the use of shell181 in order to obtain reliable results.

Why?


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[Kottier]

I'm going to find out why they thick so in a few days, there's a meeting scheduled.

But I hoped that some-one could tell me, if doing a linear buckling analysis with shell91 is inreliable or not.

 

[Drej]

Although I'm not 100% on this, there is nothing in the help file to suggest this element is UNSUITABLE for linear buckling, except maybe for a small note on shear transfer -- which could lead to UNRELIABILITY in results depending on your model (no shear transfer between layers could lead to a highly conservative buckling load) -- in the shell91 help file which you should be aware of. A Google search revealed that other people have used this element also, which you should check.


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