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My model is a cylinder under internal pressure. The cylinder is fixed in three supports along the length and the material is steel. According to physics of the model, I think there is no large displacement in that model. Do you think it needs to be run with NLSTAT large displacement? How about running with nonlinear material simulation?

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Hi,

If the problem doesn't involve any large displacement, you can just try with NLSTAT where materail nonlinearity will be taken care.

 

Regarding FSI models, I am waiting for experts view. But from .cci file I can see that the solver couldn't make a connection after 2400 secs

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Do I follow OS-T: 1520 Finite Sliding of Rack and Pinion Gear Model or OS-T: 1500 Nonlinear Implicit Analysis of Bending of a Plate?

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Hi,

 

I don't have access to tutorials right now. But you can search in form for information and examples on small displacement analysis

 

This is one tutorial I remember for NLSTAT small displacement analysis... OS-T: 1360 NLSTAT Analysis of Gasket Materials in Contact

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Hi

Do you mean the following tutorial? Its fem file is in attachment.

In my model, since the supports are not symmetric, there is no symmetry in the whole model. Therefore I have to model whole cylinder. Furthermore, there is no gasket so there are no contact surfaces.

gasket_model.fem

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2 hours ago, Prakash Pagadala said:

Follow the same process shown in tutorial, but don't add PARAM>>LGDISP and in load case refer NLPARAM card in just NLPARM AND NOT TO NLPARM(LGDISP)

Could you please set up attached fem file according to your suggestions above?

Thank you.

gasket_model.fem

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Hi Prakash

Is it possible to have cyclic internal pressure in a cylinder then do implicit analysis on it, please? The internal pressure is a function of time.

Thank you.

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If I understood correctly, the pressure loading follows a cyclic frequency (time).

 

If this is the case you can use Nonlinear transient (implicit) analysis where the load is applied WRT time

 

Please refer to this post:

 

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Can NL_DTRANS.fem be used for small displacement, as well? I need a dynamic implicit simulation for a cylinder under cyclic internal pressure. According to the physics of my model, there is no large displacement in the cylinder. However it can have nonlinearity in material which is steel.

Thank you.

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Hi Prakash

Could you please let me know how I can have a static subcase with a DLOAD? Furthermore, how may I use dynamic subcase to use DLOAD?

Thank you.

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Hi,

 

DLOAD is used for dynamic analysis and can't be used for a static subcase. 

 

You can use DLOAD for linear transient, NL transient, FRF analysis, for example. 

 

Tutorials for the same are available on OptiStruct help. Please refer the same on how to set up.

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Hi Prakash

Is there any way to have a better displacement contour for attached figure, please? There are some disturbations in contour. It is for a transient analysis. I would like to have a very smooth contour.

Thank you.

Disp.PNG

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Hi Prakash

Even by using Simple Averaging method, still there is no smooth contour. What is the possible source of this problem and how to manage it, please? It happens when a model has high number of elements and specially in transient simulation that needs to do high number of iterations.

 

By the way, is there any news about the FSI tutorials error, please?

Thank you.

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Hi

Yes, it is happening for all time steps in the transient analysis. The model has more than five million elements and the simulation has been run on a cluster with several CPUs; it took a few hours to finish.

Thank you.

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