Elemental System

AM_20700

Is there a way to visualize or set the elemental system?

I simulated a shaft that is subjected to a longitudinal (global X direction) force. I calculated the stress to be 0.313 MPa. When I plot the XX stress in the global system, I get the correct value everywhere:

When I plot the XX stress in the elemental system, I get the correct value at 2 quarters of the shaft, and a value of 0 in the other 2 quarters:

When I plot the YY stress in the elemental system, the values are mirrored:

What is going on? I suspect that the elemental systems were flipped when I meshed a 1/4 of the shaft and then mirrored it twice. But how do I control the elemental systems, or at least visualize them?

PaulAltair

In HyperMesh, you can review the orientation in the pre-processor: using the 'orientation' review tool (search for it or use the magnifying glass icon on the 'Normals' tool in elements ribbon)

This allows you to review element orientations

For some solvers (e.g. Radioss) you can request orientation as a 'result' in and of itself to review in post.

If your material is isotropic, then the element orientation does not really matter, i.e. your model is ok as it is now. but if you want to re-orient the elements you can do this in Hypermesh too.

AM_20700

Paul Sharp_21301 said:

In HyperMesh, you can review the orientation in the pre-processor: using the 'orientation' review tool (search for it or use the magnifying glass icon on the 'Normals' tool in elements ribbon)

This allows you to review element orientations

For some solvers (e.g. Radioss) you can request orientation as a 'result' in and of itself to review in post.

If your material is isotropic, then the element orientation does not really matter, i.e. your model is ok as it is now. but if you want to re-orient the elements you can do this in Hypermesh too.

Thanks.
Now that I can visualize the misalignment of the elemental systems, how do I correct/align them?

PaulAltair

actually, having looked, I don't think there is a way to update it in HW, without a script (except by manually redefining the element connectivity one by one)

As I said in first post, there is rarely any need to do it though, the orientation doesn't matter. in most 'real world' meshes, the mesh is not regular as you have in your tube and then elemental orientation wouldn't make sense at all.

It would really only matter for composite/orthotropic material definition and only then in some limited cases (as then, you usually set a material orientation separate to elemental), you can do that by using the material orientation tool. 

This though would simply set a 'correction' angle on the element (BETA) depending on the FE code. It doesn't actually update the element orientation

Michele Macchioni

in the same orientation tool you can use "orientation tab"

See below