Hi Clemens! Thanks for your kind help!
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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).
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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?
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Ok, I´ll take this into account when I have multiple load-cases. Thanks!
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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.
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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!