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Victor
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Comments
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Yes, I intend to add rigid body too.
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Not usually. But it's hard to tell from the picture if there's anything else going on. If you're using the CCX solver, those kinds of sharp corners with large thickness can sometimes cause it to fail. There will likely be more error in that region …
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The graphics are only single-threaded.
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That's probably just an artifact of the display if there are sharp corners since it displays each element as a prism.
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Yes, I'll add point mass for CCX soon. Center of gravity is going on the list but I can't promise.
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You can use Shell offset under Mesh tools -> Element properties to move the midplane by half the thickness.
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Unfortunately, offset shells won't be correct with dynamics because the offset is ignored in generating the mass matrix. That means the mass is at the mesh nodes while the stiffness is offset, so there's a spurious rotational inertia. If you don't m…
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Yes, it does disk swapping when it detects there's not enough RAM. The solver (Pardiso) also optimizes the ordering in the matrix so there's no need to consider node numbering in the model. Bonded contact creates constraint equations between each …
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This is pretty unscientific but I found 21 sources (journal articles, books, FEA software manuals) that describe the Tresca criterion: 3/21: Tresca stress refers to maximum shear stress 1/21: Tresca stress refers to 2*maximum shear stress 2/21: Tre…
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Will it be OK if you can just control the color instead of thickness? The mesh lines are the same thickness and I guess they're visible enough because of the contrasting color. This idea of selecting things in the graphics area is hard and I probab…
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Yes, fixed nodes can be used with contact because it's done with elastic springs so it's not subject to possible conflicts of MPCs the way bonded contact can be. But you should be able to fix only the surface, not the whole interior. If you fix the…
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Mecway's internal solver beam elements are only Euler beams which means they have to be slender as well as other limitations. Also, no shear stress output. In principle, CCX's expanded beams should be more accurate. However, they sometimes have weir…
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You can't do that in Mecway but it should be possible with your CAD software, at least joining the manifold edges. You can also install the Netgen app which has a tool to heal geometry. Other people have found it useful but I haven't used it myself.
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It's arbitrary. That's a good point that it should follow something predictable. I'm not sure what though. There might not be any currently selected one. Maybe it can just remember the most recently selected one. If you're editing the .liml file, t…
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Thanks. I'll do a rough survey of literature and see if there's any consistency to this. Do you have a suggestion for an alternative name for this quantity? Perhaps "Tresca stress × 2".
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I can't find any evidence that the term "Tresca stress" means maximum shear stress. I think it's just a sloppy ambiguous shorthand. Neither the page you linked to nor a textbook I have which covers the topic use that term at all. My textbook does de…
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Mecway calculates Tresca stress as the maximum difference between principal stresses without dividing by 2. If you're seeing results that are not that, it could be due to node averaging and lack of mesh refinement. As for whether it should divide b…
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It's just as well it's not obvious because it's wrong :P Sorry about that! You can have a restoring force that depends on displacement in the form of a linear spring. The reason not to use linear is really that displacements and rotations don't upda…
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It requires nonlinear dynamic response analysis. Nonlinear because the restoring force applied by gravity depends on the displacement. Dynamic instead of quasi-static because quasi-static only produces solutions that are in static equilibrium at eve…
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I've reproduced the problem that the ccx.exe 2.15 on dhondt.de can have obvious random errors with modal vibration (*FREQUENCY) that the single-threaded version included with Mecway doesn't. Here is a solution from the multithreaded one on the left …
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Yes, at some stage, I'll look into those earlier reported eigenvalue problems. Just a note that when it says "Using up to 8 cpu(s)", that range does include 1 and it used to be only 1 for the single core version.
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Yes. The CCX from dhondt.de is compiled for multicore but the one with Mecway isn't. I'm surprised it still does that with stiffness and stress though. The multicore versions usually fail more test cases than single core and sometimes produce bad re…
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You mean in the solution? I'll see if I can add that. Can you identify which material properties are most useful besides density?
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It used to be that way (dark/light) but mostly it doesn't matter which side is which so it would usually be an unnecessary detail. I'll probably fix Automesh 3D to allow either.
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There's another limitation of Automesh 3D which I realised isn't mentioned in the error message. Shell elements have to all be oriented the same way (inwards or outwards). The sides of the small shaft are inverted. Use View -> Show element axes t…
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No multi-select, sorry. Only the new menu items. Also delete empty/delete unused/etc. for named selections.
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Not sure if I'm properly understanding this, but it seems like you can already calculate the cold shape and just need modify the hot shape to that without any stress, is that right? For that, you can use non-zero displacement constraints at various…
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That probably makes sense now that default component doesn't have to be there. I'll need to check for possible side effects but I'll add it to my list for next time.
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It's effectively the same as a beta but if no bugs are discovered, I'll make it the final one. One already was (regression to v9 behavior of element selection on wireframe) so I've now updated it to rc2. Once the download page is updated to show ve…
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That's an estimate of the error in the stress that newer CCX versions (2.12-2.15) generate. It's described in the "Gradient error estimator" section of the CCX manual.
