Hi Clemens! Thanks for your kind help!
Sorry, but if I select Line-load option the membrane seems not loaded while the beams does. Conversely, the results look better if I just select the Point-load option (i.e. the membrane appears loaded and transmits the force to the beams).
You can check in the figure below that the 2nd order analysis displacements (Disp.II panel) are huge in comparison with those obtained from Non-Linear and Large-Deformation analyses. Should I understand that I get such wrong results because the membrane has not been pre-stressed? If so, how would it be pre-stressed?
Ok, I´ll take this into account when I have multiple load-cases. Thanks!
I´ve installed the last Karamba 3D WIP and compared the results between Non-Linear (NL) and Large Deformation (LD) analyses Membrane2.gh (82.4 KB). If you play with the “Beam/Subtriangle Subdivs” slider you will check that the maximum displacements and membrane shape smoothly converge for both analyses, so it looks great! However, I can´t find the way to show the Von Mises stress or Utilization % in LD analysis. ShellView only produces output for Cross-section Render Setting. Why is this so? It would be great comparing the results from both types of analysis.
After this initial comparison, I´ve set False the Bending input of the MeshToShell component (in Materials Cross-Section group) to test your brand new membrane finite elements. Unfortunately, the Non-Linear component crashes and complains with the following error (with all solution procedures):
[“1. Unknown error occurred while solving for the structural response of the system. May cause errors in exported models.”]
The Large Deformation component also crashes, but with a different error:
[“1. Could not calculate deformed model. Use the component ‘Analyze’ to get details.”]
The Analyze component says:
[“1. There are 6 rigid body modes in the system. This means some parts can move freely without causing deformation. Try to use the ‘Eigen Modes’-component and activate the display of local coordinate axes: The first eigen-mode will be the rigid body motion. If this does not help, check whether you have a pinned support directly attached to a hinge. A hinge introduces an extra node which may cause the problem. When analyzing a flat shell structure one has to lock the rotation perpendicular to the plate in at least one node.”]
Accordingly, I´ve checked the normal modes and the membrane blows out above and below the triangle plane…
- By the way, I can´t adequately visualize the normal modes (with Bending of shell elements set to True). I can only visualize something if I set the Result-Case from Model View component to number 4… but I haven´t used Load Cases yet…
Am I doing something wrong? Is Karamba 2.0.0 WIP ready to model this kind of membrane systems or should we wait for the final release? Thanks!