Karamba 3D Stress Lines

Hi everyone.

I'm new to Karamba and I would like to make a structural analysis on a concrete panel (which is part of a shell structure). I'm interested in finding the principal stress lines through the solid of the panel.

I populated the geometry randomly of the panel as the source input for the stress lines. However, as can be seen in the picture below, the stress lines are only drawn on the surfaces of the mesh, not inside the volume.

I have several questions:

1) Is it possible to visualize 3D stress lines going through the solid?

2) Is populating the geometry randomly a good source input for the stress lines?

3) How would you find the (let's say four) most principal stress lines?

4) Is it possible to use a surface as a support instead of a node?

5) How would you easily extract a stress line with a slider?

Could anyone help me out please? Thank you.

Attachments:

New Panel Karamba.gh, 23 KB

Replies to This Discussion

Permalink Reply by Karamba3D on August 12, 2016 at 5:55am

Hi Erik,

at the moment Karamba can only do calculations with trusses, beams and shells. Solids are not included. One of the reasons for this is that volumetric finite element calculations are computationally expensive due to the large number of elements one needs, to get results of acceptable accuracy. Another reason is that the large number of results is hard to handle and interpret. A third reason is that in structural engineering it is normally not necessary to use volumetric calculations.

In Karamba you can visualize the principal stress lines on an arbitrary layers between the top and bottom of a shell element (e.g. 'Layer of results' in the 'ShellView'-component), but not principal stress lines in thickness direction.

In each point of a shell under plane stress there are two in-plane normal stresses and on shear stress. These stresses depend on the coordinate system under which they are viewed. It is always possible to rotate that coordinate system so that the shear stresse is zero and the normal stresses are a maximum and minimum with respect to the rotation angle. The coordinate axes then point in the principal stress directions. The principal stress lines are curves which are always tangent to the principal stress directions. Therefore there is no most principal stress line.

For supporting a structure surface-wise place nodal supports on all nodes which are situated on that surface. The same works for line supports.

In Karamba 1.2.1 you can extract the minimum and maximum Van Mises stress using the 'Utilization'-component. Another option would be the 'ShellVecResults'-component.

Best,

Clemens

Permalink Reply by Erik Pelicaen on August 14, 2016 at 4:10pm