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Crashphys

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  1. Go to tools -> BCs manager on the top of your screen. Everything else is done the same as HM 2017
  2. Your suggestions all worked. Thank you for the help!
  3. Hi, Sorry yes I do. It does not seem to give indication of any errors, but I do have this warning: The structure of surface-to-surface contact element is quite different than that of node-to-surface contact element. No internal CGAP/CGAPG elements are created for surface-to-surface contact.
  4. Hi, I implemented the changes as you suggested and they were very helpful. It now works well, but for some reason the contact interface for the bottom is not working right (see image below). Do you have any ideas why? I have not been able to figure it out. Thanks
  5. Hi, I am trying to model a punching simulation in implicit, but upon contact the model basically explodes like the picture below. I have successfully modeled this in explicit, but I would like to try it in implicit and compare. Can anyone suggest why this is happening? When it happens I get an error: *** ERROR # 4965 *** Maximum number of time increment cutbacks reached, analysis aborted. *** ERROR # 5905 *** Severe element distortion detected, analysis aborted. I set NCUTS to 50 using NLADAPT card. I suspect something might be wrong with the contact interface perhaps?
  6. It's better if you share the model so far, but from the looks of it you have only one response set up. You need to have a volfrac response set up in order to set a constraint on it, and it does not seem you have one. Revise your steps during the volfrac response set up.
  7. EDIT: Problem solved. Hi, I am trying to perform a simple 3D beam non-linear bending analysis and get the following error int he attached .out file. I have attached the .fem for reference. Can anyone help me out? *** INTERNAL PROGRAMMING ERROR *** in file "hexa8_bb_ls.F", at location # 158. ioerr(1) = 995 **** ABORTING RUN DUE TO AN INTERNAL ERROR ****
  8. In case anyone is ever wondering, I finally got around to trying this and Robert's answer works. Thanks Robert!
  9. Hi Simon, I guess this is not so much a software problem but a theoretical one but: Considering there are both loads and displacements applied here, if I wanted to optimize this is there a way to address this if I wanted to run OS optimization with stress constraints?
  10. Hi Simon, Thanks again for the help. In this case, loads are applied and not displacements. That's what makes it all the more confusing... Worth mentioning also: For all load cases, compliance appears to increase with increased core thickness.
  11. Hi, I am modelling sandwich panels applied to a wall with loading in various cases. In sandwich theory, the stress should decrease with core thickness. However when the core is thick here, the minimum principal stress is much higher than when the core is thin. I am aware there is a high load specifically at this point in specific so stress is high, however stress should still decrease with increased thickness. I am wondering if anyone has an explanation to help me understand? Thin Composite: Thick Composite: forum.zip
  12. Thank you for letting me know. There goes 7 days of my life :'(
  13. I think there are a few issues in your model you need to fix. At a glance, your INTER/TYPE7 has a set gapmin of 0.1. This implies that anything within 10 cm of your impactor is in contact with it. Meanwhile, your impactor starts only ~1 mm away from the foam, which implies your impactor is penetrating 10 cm into the foam from T=0 seconds. Unfortunately my solver is currently bogged down with some other work, so I can't play around with your model. Make sure you read up on TYPE7 Interfaces in the reference manual. I recommend gapmin to be 0.1*(smallest 3d elem edge length) as per recommendations in the manual.
  14. Time until a solution is attained is variable and depends on your time step heavily. If your elements keep distorting, your simulation may start at a 3 hour solve time, then when it calculates the next stage it will estimate 3.5 hours due to the deformation. You can achieve reduction in sim times with DT/NODA/CST or AMS (see video). You might also consider the multi-domain method.
  15. The model you are working with would help in finding you a solution. Which composite? How did you model the bird? Just like how no one can correct your code without seeing what your program is line-by-line, no one can guess what your simulation is doing. I have attached a bird strike simulation I performed on a GLARE plate from a while back. Let me know if it works for you. GLARE2_0000.rad GLARE2_0001.rad
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