element for vessel

[payaam2000]

Dear All

I am a new user of ANSYS 11. I am going to model a pressure vessel with a nozzle on it. This means that vessel is not symmetric.
the loads are inside pressure and external force on nozzle. I want to know:
1- which element number should i use?
2- can i prepare model of the vessel in autocad and then transfer it to ANSYS? if yes, which extension of autocad export file is the best?

Thanks

 

[TGS4]

Depends - do you want to use shell elements of solid elements? What's the purpose of the analysis? What will you do with the results? How will you know what you have modeled accurately reflects the real thing?

(BTW, these are typical questions that every engineer should ask every time they pick up an FEA program to simulate anything.)

 

[payaam2000]

Dear TGS4

kindly be informed that i need 3 dimensional stress and at final stage i want to linearized the stresses in order to find bending stress & membrane stress.

would you please help me.

best regards

 

[TGS4]

Perhaps I wasn't clear the first time around:

1) Do you want to use 3D shell elements or 3D solid elements?
2) I understand what you want to do with the results (linearize stresses, etc). But, What's the purpose of the analysis?
3) How will you know what you have modeled accurately reflects the real thing?

and one more for good measure - linear or higher-order element?

Have you ever evaluated a pressure vessel FEA before? If not, do you have adequate mentorship for this task. It's not as easy as it looks.

 

[payaam2000]

Dear TGS4

Kindly be informed:

1&2- I need Sx,Sy,Sz,Txy,Txz,Tyz and at final stage i want to linearized stresses in order to specify bending stress and membrane stress. I don't know 3d shell or 3d solid element have these out puts or not?
3- I can evaluate that if FE model is accurate because stress in cylinder component of pressure vessel can be calculated by the rules.

As a background I have studied and modeled ANSYS 10 examples from tutorial file.

thank you for your consideration
looking forward for your reply

 

[TGS4]

OK - if you don't know whether you want shell elements or solid 3D elements, then there is a much bigger problem than you think. And you won't find your answer here.

Again - Have you ever evaluated a pressure vessel FEA before? If not, do you have adequate mentorship for this task? It's not as easy as it looks. Are you following any particular Pressure Vessel Code? Have you read any literature (journal and conference papers, textbooks, etc) on this topic?

 

[payaam2000]

Dear TGS4

Kindly it is requested to give a brief explanation about this subject and introduce a reference book or article or web site in this regard.

Thanks a lot

 

[TGS4]

http://www.google.com

http://www.eng-tips.com

Start with searching the latter. I also have very good luck with the former. I would also recommend store.asme.org, but you'll have to pay for those papers.