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MikeMcMullen
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The paper is quite helpful. The recommend values are also reasonably consistent with recommended values I have seen. Good luck on the example problem!
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Note that I actually do not use FEM for dealing with "allowable" stresses in concrete as these have been set by codes based on much simpler calculation methods before FEM was well developed, and may be narrowly applicable. I use it for problems out…
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For this example, of flexure in a solid beam, the tensile strength used normally would be "modulus of rupture". In reality it is dependent on the depth or volume of the tensile zone and is higher than the splitting stress as the extreme stress zone…
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Tensile strength in concrete has many definitions for concrete and in reality they vary a lot depending upon what they are used for, how they are tested, the sample size, prior strain history, and due to extreme variability compared to modern steel,…
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Ooh. That would be wonderful. Especially if it worked with Mecway. If I read the manual right it only requires a few more cards than the compression only approach, and a knowlege of the friction angle and dilation angle. There are a few examples…
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Calculix 2.21 now includes Mohr Coulomb. What we need is a good reinforced concrete example using it. It would still not include the specific non-linearity of concrete in tension and compression, but may be good enough. Some mentions from past im…
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To be expected. The first half dozen to dozen attempts are in single precision which is usually an order of magnitude faster on most machines, but about 7 digit accuracy, but in long sequences of calculations rounding and truncating errors will red…
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I have had some luck. There is an approximation for the tensile strength that works ok for matching bending tests of cracked reinforced concrete that uses a tensile strength of about 0.30mpa to 0.60 mpa or so and nominal reinforcing of perhaps 0.1…
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I have a suspecion that this partly depends on the ratio between memory bandwidth and core speed. Most problems require at least the solution out of cache, usually most of the calculations, and L3 is usually shared. Looking through the literature …
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I have been using the version 23 beta for about 2 weeks with no issues related to the program, and it did pick up some badly shaped elements not found before.
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I have been looking for cracks. Note stresses seem pretty regular, just deflections, and often unusual directions. Also having convergence issues, though sometimes reaches solution, though this may be expected with the compression only concrete mo…
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I routinely work with meshs of about 2M nodes (using quite a bit of page fileing). They take a couple of hours on my 64 GB machine, though I usually run non-linear which is much much slower than purely linear problems. At this size viewing mesh or…
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It appears that the problem runs OK, though convergence is iffy. I got the stresses etc to show. Problem was that element and model edges obscured the color. The deflection of bars is still iffy not being very close to the concrete they are attac…
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Seems to be a difficulty keeping the common nodes common between Mecway and CCX with the forced rectangular element which has the nodes at the corners of the shape, and the Mecway truss members which have the nodes along the CL. I will need to chan…
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I think I thought out what the problem is. I think video card latency as the model gets larger causes the existing node to not be found quickly on the second pick for the line 2 element creation. I am running a Nvidia 1660 Ti. Used to use a Ryzen…
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I will work on this a bit more. I think that issue may relate to the phrase "existing node". When I try to click on existing nodes, sometimes it selects an existing node, and sometimes creates a new one. I have no clue why one case and not the ot…
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4 to 6 x added nodes does not sound bad. I may try again. My main issues were difficulties generating the truss members, the bigger problem being not snapping on the second point, but treating it as a manual point location. that when located in th…
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I agree, but my thinking is that looking into the python used for the freedad examples may give a clue to what needs to be done in Mecway. I think the Freecad uses Calculix for this exasmple, but I am not sure.
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I think there is a similar example in FreeCAD. https://youtube.com/watch?v=VQINrNWdOHo
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I am probably never going to do this, but can you potentially show progress by using two instances of Mecway, one running the Iron python script to run the problems save them, and alter run and save again with an incremented name, and another instan…
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May be vaguely related to what I found running largish problems on my Ryzen 3700X, 8 cores, 16 thread, two channel machine. I found that assigning 8 cores/threads was slower than 6, and 4 only a few percent slower than 6, and more memory was needed…
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That location no longer works for accessing those DLLs, and the later fersion from 2023.1 or 2023.2 don't work for downloading, at least with a computer with an AMD processor. Older dlls work with other compiles. I have yet to try downloading from…
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Started playing with this yesterday. Internal solver is very fast. The CCX provided is not as it seems to single thread. Not your problem, but I also Looked at Calculix 4win2.21 and have difficulty with getting the appropriate MKL dlls for the dy…
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I think it is a limitation of the implicit solution process in general as often there is a problem with converging on a solution if the resistance does not increase at least a little with increasing strain. Therefore the material models are not per…
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14.4 GB was probably related to a point relevent to an 8 GB or 16 GB laptop with a slow hard drive.
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This may help me as well. 100 GB might have been faster simply due to never getting out of core. I dealt with some of these issues by increasing virtual memory which worked pretty well for problems needing up to 160% of available ram, above that g…
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If this uses the Pastix solver I had this issue a couple of years back. Someone (3rav?) did a recompile with i8 for me that corrected this. Otherwise use Pardiso with the intel speed ups. The advantage of Pastix seems to fade somewhat for larger …
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I am always careful not to post due to potential prior art. Lurk instead so I can pick up bits here and there. May get back to running some simpler FEM problems after a while. Buckling always interested me (especially plastic post buckling behavi…
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Buy two licenses. I did, but it was due to a very fatal CPU/MB crash, until Victor sent me an e-mail after I had purchased another, I had lost the KEY due to this crash. He offered to refund me the price of one of the keys, but I refused due to hi…
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Correct about Freecad, and I don't use it for that reason. Its method of just defining constraints and relationships has its virtues when the dimensions are unknowns, but I don't work that way. That is the part of the design process that I occupy.…
