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Crashphys last won the day on May 23

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About Crashphys

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  1. 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 **** Bottom_Lead_PunchSim_Implicit_NoJig.fem Bottom_Lead_PunchSim_Implicit_NoJig.out Bottom_Lead_PunchSim_Implicit_NoJig_001_nl.out
  2. In case anyone is ever wondering, I finally got around to trying this and Robert's answer works. Thanks Robert!
  3. 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?
  4. 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.
  5. 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
  6. Thank you for letting me know. There goes 7 days of my life :'(
  7. 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.
  8. 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.
  9. 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
  10. There's a few kinematic issue in your model. I think the fact you are working on a skew is resulting in lots of pain, so if you can remake the model not in a skew, I would. I don't have much experience with rigid walls, but from what I can tell: - You did not set any skew for your velocity. I went ahead and change it so it moves in line with your created system. - You were constraining the whole model in the up/down direction while also applying gravity. I applied gravity on your model and constrained only the floor in the up/down direction. - I cannot figure out why the rigid wall has incompatible kinematic BCs. Perhaps someone else will be able to chime in on this. Make sure to review rigid walls and ensure you have implemented it correctly. Try running a tutorial with one first. Incompatible kinematic conditions means you have done something like apply motion and restrict it at the same time on a node or something. test_0001.rad test_0000.rad
  11. Crashphys


    Cannot tell you why without knowing which tutorial or model, however if you would like to view your simulation results, you can just open the animation (_A00X) files in Hyperview instead and all your results will be there.
  12. Hi, In the attached video, the instructor mentions that BC's and initial velocities can be changed mid-simulation using a restart procedure. Since he specifically mentions BC's and Initial velocities, I am wondering if this also extends to other BC's like accelerations. I am currently running a costly simulation and really do not want to restart it just to change a load case that I have not used yet. I want to change a /GRAV card to an /IMPACC card. The acceleration does not begin before the point which I want to restart, so changing it will not change results prior. If I want to change accel types, will the solver read my modified starter file, or will I have to rerun my starter file for it to read it thereby erasing all my progress? I tested to see if I can change the /GRAV card by purposefully sabotaging by inputting values which should break the simulation, then ran my _0002.rad engine file. The solver carried on like normal, which implies to me that I have to re-run my starter file to change the acceleration type. If a procedure exists so that I can change accel type mid simulation, please let me know. Thanks
  13. Thank you for the help. So you think it is worth a try? If possible, would you kindly elaborate what you mean (I'm not super great with computers, not sure what you mean by scratch folder and how to set it up)? Thanks again!
  14. Hi, I noticed I have very high wall time from OptiStruct. I currently run OptiStruct on a server through my school. I am wondering: if I install an external SSD and run my .fem files off of it, will this reduce wall time? The thing is, OptiStruct itself cannot be installed on the SSD - I can only have my own files on it. So my process would be running OptiStruct on the server but using files in my SSD instead of from a local HDD. Can I expect any benefit for this? Thanks in advance.
  15. Hi, I want to model the forming procedure for a part similar to what is shown in the picture below. It is not a flat plate element but more like a square rod which is bent in a Z shape. As I understand it, the best way to do this will be with solid elements but there doesn't seem to be a way to do this other than with a pipe forming simulation. Can anyone advise me on similar tutorials? It is important I model the stresses due to forming very accurately. Thanks
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