How to curve quadratic elements

[Vocs]

Hello,

I'm having trouble in meshing a plane model using quadratic shell elements in Abaqus CAE. I have to model a quarter of circle and I want the elements on the border to be perfectly coincident with the external circumference. However the mesh created by Abaqus has just the nodes on the circumference with straight lines connecting them. How can I curve the elements to match all the circumference?

Thanks

 

[portliner]

CAE sometimes do NOT place the midside node on the underlying geometry to avoid bad forming elements. You can bypass this by increasing the seeding.

You can use the, mesh > edit, function and project the nodes to the geometry, boring!

 

[johnhors]

The nodes are on the circumference, beyond that what do you expect? The boundary of a quadratic element is as the name implies defined by a quadratic equation. No pre or post processor is going to bother drawing this quadratic curve on the screen!! Besides a circular arc cannot be represented by the quadratic shape functions of these elements, therefore the element boundaries will never perfectly match the circumference. I suggest you create a finer mesh!

http://www.Roshaz.com

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[Vocs]

Thank you very much for your replies. I thought that Abaqus could draw the quadratic shape of the elements on screen as other fem softwares that I used in the past do.

 

[johnhors]

I thought that Abaqus could draw the quadratic shape of the elements on screen as other fem softwares that I used in the past do.

I can understand a p-method based fem computing the boundary curve from the element shape functions for display purposes, but I am not aware of any h-method fem (like Abaqus) using anything other than straight lines between the nodes of an element in a display.

What are these "other fem softwares" that do?

http://www.Roshaz.com

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[Vocs]

I used Straus7

 

[johnhors]

Vocs, yes you are correct Straus7 (or Strand7) does indeed compute and plot the curve for element boundaries on quadratic elements.

However Strand7 uses the old windows GDI graphics system, whereas Abaqus/CAE (along with all other vendors except Strand7 !) use OpenGL graphics. I know which I would rather use.

http://www.Roshaz.com

quality, cost effective FEA solutions

 

[Vocs]

Ok, do you know if there is a way to force Abaqus to draw the real shape of the elements? My current model is small so I won't have any graphical performance issues.

 

[johnhors]

"Ok, do you know if there is a way to force Abaqus to draw the real shape of the elements?"

No, you will not be able to do this. You either go back to Straus7 or write your own software to do this.

http://www.Roshaz.com

quality, cost effective FEA solutions