2d element orientation / Tensor Component Syy

Rahul_P1
Rahul_P1
Altair Employee
edited October 2020 in Community Q&A

I observed some problems while analyzing my structure in HyperView. I still put my thread in the preprocessing forum, as I think the problem arises during preprocessing.

iyi0s-HyperView_Tensor_Component_Syy.jpg

The tube is meshed with 2D -> automesh -> QI optimized.
Mesh type: mixed
second order elements

The surfaces of the lower section (and also top section, which is not displayed) of the tube were trimmed to get a better mesh orientation in the middle section of the tube.

I would expect all Syy vectors to point into the same direction. So they should point from bottom left to top right in the picture. But some (in the trimmed section) are pointing in a perpendicular direction. This direction (in my opinion) should be Sxx and not Syy.

Is there any possibility to change the orientation of the affected elements?
BTW: The shell normals of all elements is pointing into the same direction. But I think this wouldn't affect the orientation of the element x and y axis.

What else could be the problem?

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Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited May 2015

    monoton,

    There are several interesting things to discuss in your topic,

    Firstly the elements that have the Syy in perpendicular are deformed as can be seen in the image.

    Secondly we have to keep in mind that after solving the solver writes out the results for each element, this then is read by HyperView, For Quad elements, the reader automatically selects one of two methods of the elemental coordinate system.
    see this topic below
    Forum » Visualisation (Postprocessing) » HyperView » Prinicpal stresses vector and graphic information

    Thirdly I see from your image that you are using version 10.0 or 10.1, is that right? what is the update you have for your tool, please check with help > updates and system information.

    Use the projection rule to visualise the stress components with different projected coordinate systems. For shell (or planar) elements, results in any 3D coordinate system can be projected onto the element plane, the projection rule defines how the local x axis is obtained, this will give different directions for your Syy.

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited May 2015

    Rahul,
    Thank you for your helpful input!
    I could solve the problem - at least for the analysis, which I need to do.
    Maybe I'm missing little more background knowledge, but for me it's sufficient to define a local coordinate system.
    Actually I tried it before I opened this thread, but I didn't succeed.
    Now, maybe just by chance, I've seen, that the ID of my (in HyperWorks defined) local coordinate system is not the same ID as in HyperView. After realizing it, I was able to obtain the correct stress plots.
    Best Regards,
    monoton

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