Learning Forum

[yogeshr]

I am importing very thin tube for modal analysis from space claim to workbench , I want to know what is the accuracy of geometry in workbench . Or is there any setting ine has to set for using high accuracy geometry from space claim to workbench.

[peteroznewman]

If the tube is a solid model, I recommend you create a Midsurface to replace the solid and use shell elements in Mechanical to do the Modal analysis. If you do that, the stiffness of the model will be accurate. If you use solid elements, you will have a risk of an overly stiff model unless you have a few elements through the thickness of the tube wall. This is not an issue once you have shell elements.

If you mesh the tube with linear elements, you will get a faceted model, which will lose the accuracy of the geometry. But the default mesh uses quadratic elements that follow the curvature of the tube more accurately. The higher the mesh density, the closer will be the accuracy of the mesh to the geometry.

[Sandeep Medikonda]

Yogesh,

  I recently came across this nice article which I thought explains accuracy in FEA very well. 

  Hope you find it useful.

Regards,

Sandeep

[yogeshr]

@peterroznewman , thanks for your prompt reply , I am using solid elements with minimum two elements through thickness , I want to ascertain that whatever changes (microns 10) i am doing in thickness are reflected in analysis , one way of ascertaining was to check the change in weight which is reflected in the solution information. But I want to know is there any geometry import setting which can be checked to be sure whatever result  I am getting is accurate ? 

[yogeshr]

Yes it is very useful , thanks . I am more interested in checking the geometry in workbench . Like we put dimension annotation in our spaceclaim model.

[peteroznewman]

yogeshr,

I know of no setting that can change the accuracy of geometry import. The originator of the geometry may have a setting to adjust accuracy. Sounds like you have a way to check that a 10 micron change made a difference in the mass.