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DaveStupple
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The Young's modulus thing is definitely my error, I'll try to understand how that happened. The non-reproducable thing may have been me too. With Poisson at zero, the empty solution was very unsymmetrical. I tried Poisson 0.45, and the empty solut…
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Hi Victor, I did try non-linear earlier but it did not solve, but I have tried again now and have results. Maybe it defaulted back to internal solver and I didn't notice? I attach two files because they solved slightly differently for the full con…
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I set the material to be 1 mm thick and to have modulus 400 MPa in-plane and 100 MPa through plane (based on guesswork), with density 400 kg/m^3, and it now collapses when empty and self supports when full. I tried a Poisson ratio of 0.3, but it cau…
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No need for apologies, Victor. Thanks for the intervention, I'll have a play with that model and see if it gets me any further. I think I will have to introduce orthotropicity to the material so that it holds its shape a bit better when full, but it…
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Just realised that some of the configs etc. are not saved in the files, but it should give an idea of what I am trying to do.
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Hi Sergio, Your dxf imports OK for me (Mecway 9.0, 64 bit). I chose mm when it asked what units. Dave
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*geometry I can't see how to go back and edit my post... I am sure I have edited posts before. Edit: It seems I can edit comments, but not original posts.
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Hi Dave, Configurations might be your answer, look this up in the manual. I haven't used them myself, only had a quick play. As far as I can see, changes to the mesh or any individual load/constraint will be applied to all configurations, which is …
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Thanks Victor & Sergio, Victor, the braze would be a thin layer where the optic and the ring share a face now, so no shared edge, though the two bonded contact surfaces would be quite close together. That wedge-shaped gap would need thinking ab…
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Johan, Strange! It looks like it might be reading your temperature (specified in °C) in K. I changed the units here to K and added 273 to each temperature and the results are more sensible, I think.
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Can I ask what RGB stands for? Googling this didn't help.
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The evaluation copy of CurveExpert is pretty useful.
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This might not be your problem, but the units can sometimes be not visible and therefore easy to set wrong. See the end of http://mecway.com/forum/discussion/comment/2113/#Comment_2113
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Ug, There is a dropdown menu at the right of the modulus entry field, use this to choose your units. If you already have a number entered, Mecway will convert, so be careful! What I mean is, if you change from MPa to GPa, Mecway will change your 275…
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Also, Solid Edge offer an (I think) fully functional version for students, that you are not supposed to use for commercial work.
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Just a shot in the dark... having Preview Pane enabled in Windows File Explorer can affect other programs in bizarre ways (scaling etc.). Try switching off Preview, then open a fresh Explorer with Preview still off.
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If I leave the inertia on the x-axis, and set the material density to 0, the solver fails, presumably because there is no resistance to the moment, as you predicted. Makes sense.
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Thanks for that. I initially assumed it was to give the rotation some resistance, but then I noticed the inertia was applied for an x-axis. So maybe you should apply it for the z-axis? I tried this and got a kind of sinusoidal pattern on the rotatio…
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I am puzzled by the rotational inertia constraint about the x-axis. What does this simulate? I have tried suppressing it. or increasing it, but I haven't spotted the effect it has. Keep it simple for me!
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I see what happened. When I open the displacement dialogue, the units buttons are hidden for some reason. They show OK with formula selected, but are pushed out with table selected, though still just accessible.
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Mike, Victor, I think Mike has specified displacement in m rather than mm...? Edit: well I thought so, but when I changed it the solution has too small a displacement. Hmm.
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Method A: I have a uniform mesh but with quadratic elements. This method overestimated the total power by a factor of about 2. This seems quite a big error. I might have made a mistake in the calculation, or it might have something to do with the nu…
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Thanks Victor. It is heat flow rate I am after, and I should have been averagiing rather than summing. Doh! I blame too many hours sitting in front of a screen in a hot office.
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Hi Suktan, I am not very expert at this, but I can give you some suggestions for now, and later you will get replies from the real experts. I have recently been trying to simulate compression of an O-ring. http://mecway.com/forum/discussion/418/c…
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A model with lower modulus (C10=0.83, giving 5 MPa rather than 10 MPa) solves with two distorted elements. The old mesh failed way earlier than this.
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I took one of the models that showed an early mesh failure (i.e. shortly after the O-ring engages the walls of the groove, see image) and changed the O-ring mesh so that it was all hex20 elements (create>plate>circle, then revolve). It now sol…
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With the 5.75 mm groove model, I switched on reduced integration. The model now solves without the minor element failures. Next, I left everything the same and just changed the D1 value to give different Poisson ratios. Poisson 0.4857 seems to be…
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Hi Sergio, In the 5.75 mm model there were 5 collapsed elements, so I excluded these from the volume calculations. In the 5 mm model, there were no collapsed elements. I think the volume change is genuine. In the material properties, with D1 set to …
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I have done this twice now, once with a 5.75 mm groove depth and again with 5 mm, in both cases the groove width (6.5 mm) is a little narrower than the o-ring (7 mm). With the deeper groove the window bottoms out and the o-ring does not quite fill t…
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