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DaveStupple
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Finer mesh in the o-ring failed catastrophically. Sergio makes a good point about the stiffness of Viton. I will try to get some physical tests sorted, but they are likely to be quite basic to start with. I do think the model is likely to over-estim…
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Using just displacement, and calculating a C10 value of 1.68 to represent Young's modulus of 10MPa, I can solve but with a few distorted elements. When I do the same for 5MPa, it is too soft and the model fails horribly. From the 10MPa model, I summ…
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I have not succeeded with the application of force after an initial displacement. I did not use OP=NEW, I just let the new STEP do this. It goes through the motions then returns a 'too many cutbacks' error, so it must be the fault of Theresa May and…
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It is very difficult to find data. I am running three analyses with C10 values (0.17, 0.84, 1.7) that represent Young's Modulus 1, 5 and 10 MPa, which I think is a reasonable range. I have no measured data, it would be useful to try to get this whe…
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Victor, I did go back and re-read your original post more carefully and have been experimenting with a second step - not there yet, but feel I am close. I will certainly take a look at the force approach too. Will let you know. Hi Sergio, the id…
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Trying to do the custom CCX step to 'switch off' the displacement when I bring in the force... I copied the whole block of *BOUNDARY text and pasted in the custom step box, e.g. *BOUNDARY,AMPLITUDE=A_67A728BC732D 4873,2,,1 *BOUNDARY,AMPLITUDE=A…
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Oops, I see the forces there, plain to see...!
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That's fantastic thanks Victor & Sergio. Lots for me to read up on and better understand, particularly setting the values for the hyperelastic models. I will try to work with your model and bring the force in using tables. If this does not work …
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Can't see how to edit the above, but it occurs to me now that my point about the model coping with non-compressibility and limited room to expand might be not right. The model copes OK and continues to compress/expand when only dislacement is used t…
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It looks like the original poster is no longer with us, but I have a bit more to add in case it's of interest. The steady state thermal model that I have been working with lately has 69261 elements (quadratic) and 284774 nodes. Graphics is a bit s…
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Looking at the trend line of the temperature plot I notice that gradient 1 and intercept 0 are outside the given uncertainty intervals (I have not looked this up, but I would presume they are 95%). So there does seem to be a systematic difference be…
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When I plot the temperatures node-for-node from the CCX model against the temperatures from the Mecway model from which it was generated, I get a very nice fit along the X=Y line as I would hope. This tells me that the models are returning near iden…
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Gentlemen, this is great progress. I have the scaled-up model solving in CCX giving very similar temperatures to the Mecway solution. This model includes the material with the temperature-dependent CTC. Excellent news, thanks for your help so far. …
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Hi Victor, Scaling the quantities 'properly' like I did failed to work, but when I followed your recipe , it worked perfectly and the model solves in Mecway to give the same temperatures as the original. I haven't worked out why you scaled the uni…
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Hi Sergio, I'm not sure I understand the question! I created the model with Mecway, meshing manually. The model solves fine in Mecway and gives feasible results. I don't know what you mean by preprocess, so I guess that means there is no preproce…
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Hi Sergio, Thanks for taking a look. The model has internal heat in a thin film, and within the thin film the heat has both a vertical and a horizontal distribution (modelling the heating effect of an electron beam). This is the reason for such sm…
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Thanks Victor, I've tried to progress this but hit a brick wall. I'll start a new post.
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Hi all, I'm trying to get CCX to run my thermal steady state model, using Mecway 6 Beta 2, hoping that CCX will now cope with pyramid elements in the mesh. 1. I see *CFLUX entries in the CCX inp file. I guess these are representing my interna…
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Thanks for taking the time, Victor. I will have to think about this and look at the link in more detail.
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OK, I can see why the effect could be so small. In another situation, where radiation might be significant, how would you approach the ambient temperature for an object in a vacuum chamber? Is there just a relatively constant background radiation fr…
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I have attempted to use the CCX solver on my model, with the following errors: Error: pyr13 element in Thermal Steady State cannot be converted. Error: convection could not be converted. My model has many pyramid elements (used in gradi…
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Another thought, clicking on the orange 'Forum' button (top right) can sort this out.
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VMH and Sergio, No, no, no. This mesh is generated manually by a fallible man at a desk in the south of England, who has imperfect concentration and is prone to making mistakes. I laid an edge across a face (several instances) in a linear model, an…
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This works with both linear and quadratic models. The images are from the linear model. From above the problem faces are highlighted blue and easy to spot. From below (i.e. behind the faces), the blue highlight is not visible but the faces are dark …
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That's useful, as (I assume) it doesn't rely on quadratic elements. I'll try that.
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Thanks Victor & Sergio, I'll try some of these and report back. Looking at stress away from the sharp corner is definitely a good idea (and obvious, on reflection). I've started looking at Calculix but it'll take me a while to figure.
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Victor, scaling now much better, buttons are now a sensible size. I was just about to feed back on some other issues, but I think the Beta 2 has them sorted, the main one being an annoying flicker when selecting.
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Makes more sense now, thanks Victor
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Hi Victor, Thanks for looking at this. The laptop screen has 4k resolution (3840 x 2160) and scaling set to 225%. The external monitor has 1920 x 1200 and scaling at 100%. Both show the icons too small, but text etc. is fine. I tried disabling sca…
