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disla
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Start with a much-reduced model to find the right contact parameters , mesh density and material model to get a better understanding of the problem. Other problems may emerge when going to the full model but big ones would be cleaned. The problem i…
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It's a bit of a pity that you have to keep one unused to put the dummy constraint on That's the one the user wants to release.
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Example attached. Mecway warning about “Rotational DOF do not apply to beam or shell elements with the ccx solver” is sorted out. Hopefully Victor finds a way to implement this.
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Thanks Victor
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https://we.tl/t-JKQM1dZVqb
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Not sure if it was @JohnM or Sergio who posted many years ago the idea of self-contact. It works very well in this case. One needs one contact for the initial Strip , Cilinder, and a second contact with itself once the first turn has roll. Don’t o…
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I have looked the textbook theoretical solution in more detail and noticed that the Maximum tangential stress was evaluated at the mean radius not the external face. I think it's worth to update the liml file taking that small difference into consid…
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Manual warns about the inacuracy of distributing across curved surfaces. It can be seen just by redefining the C_SURf_D faces to the ones shown on the picture.
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File in a second post so if there is some comment I can update.
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Regarding what options to consider for ADJUST I would say all the options mentioned by polymathic including suppressing the ADJUST parameter as it makes a big difference. (See attached file).
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Hello, I have edit and rewrite my previous summary. Hopefully, it is more clear and not so model specific and more accurate. It only refers to the creation of the contact itself and how ADJUST affects the result at the end of the first extra step. …
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If the attached file is representative of your model set up, I have a possible explanation of why the dummy force helps to progress. Even if the contact is achieved with ADJUST as mine (Number of contact spring elements=672) the convergence can fail…
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Could you try if adding ADJUST=0.1 solves with no more changes? That can be done with modify Keyword without the need to rewrite the contact. NOTE: That will affect all the contacts if you have more than one. I have two parallel contact stacks in…
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If I’m reading properly the manual, this would be the sequence. 1-Adjust. 2-Clearance/penetration evaluation. 3-Springs generation. Points 2) and 3) may loop as the model evolves. ADJUST response to Initial Geometric Penetration (TIED) If ADJ…
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Hi, Could the adjust parameter be responsible? I’m missing it specially with unilateral. I have been trying different configurations . File attached as example. Apart from finding some combinations of master and slave more suitable than others, if …
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** Generated by Mecway 24 *NODE 1,-0.1010898679595,-0.5279358078186,0 2,-0.1011483875011,-0.5310025307924,0 3,0,0,0 4,-0.1012028779094,-0.5340692537661,0 5,-0.04410311149671,-0.1385981326659,0 6,-0.100960740244,-0.5218023618711,0 7,-0.101299…
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Wow, that’s more tricky than it looks like. The bow is under a combination of bending moment and Compressive force. I also agree with Victor that’s a nonlinear problem. Second order elements can capture better the end surface normal. That’s importa…
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Hi Mishal, Without forgetting the need to perform a convergence study, one general hint to foresee the required mesh density is to ask oneself ; how do I expected the Stress field will be?. Then put more elements where you expect more variation. Lo…
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Nonlinear quasi static step. Compression only and nonlinear only tension springs require nonlinearity. Quasistatic because I'm lifting the system linearly. Why?. Because only 3-legged tables do not limp. Better to check the lifting process when one …
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I would solve this without dynamics if the lifting manoubers is done “slowly”. I guess your nonlinear static attempts could be failing because of rigid body motions.(It has happened to me). Some hints: 1-I’m considering an only compression suppor…
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like beam ends where they seem better. I agree. On free ends they could be of big help to impose moments and rotations without noticeable side effects and regarding midspan knots is just a matter of paying attention to refinement to avoid Knots w…
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Those dark lines could then be a good help to know where some refinement would be recommended. Thanks Victor
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I have also notice that recently. Seems like the way the BC are set up affects how fast they later move. I base my comment on a recent inp file shared in the ccx forum. When the BC is applied to each node separately the graphics slow down up to th…
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Knots (ccx) may be of nice help when applied to the extreme of beams or shell elements but, when they emerge inadvertently in between the spam , they can affect considerably the results. In between knots make the expanded nodes between elements to …
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Thank you Raynotrent and standardsapplied. Nice!! . We have now a lot of options.
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Hi JohnM, I have made some progress. Deviation with respect to the direct measure is below 0.3%. Expected 0.1481 mm Direct Measure. Mean of the three nodes. Final Displacement 0.1484 mm Castigliano Deviation 0.25% …
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I’m looking for a general solution for this problem based on formula. Meantime, I built the equivalent model removing the rigid body part to allow direct measure of deflection. This is the result I’m using as reference. I’m sharing it in case someon…
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You could give it a try to this. It's free. Registration required. It's in French. https://www.cticm.com/logiciel/propsection/ I haven't test this other but was recomended in the calculix forum some time ago. https://sectionproperties.readthedocs…
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Mecway 24 has a new feature which does this I completely miss that. Now I see you have managed to build a local coordinate system aligned along the symmetry plane and following the shell face. Impressive. . I finally managed to solve 1/4 hemi…
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Sorry, the picture.
