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Mirino

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Everything posted by Mirino

  1. Thank you very much. I'm going to mesh the whole component with 2nd order tetra elements then. Anyway, why Prakash is it better to use tetra elements (2nd order) for the whole component instead of tetra and exa combines together?
  2. Hi Prakash, thank you for answering me. I notice that the second image (tetra) is different enough from the first (exa). Therefore, if necessary, is it better to mesh with tetra elements only a small part than the whole component?
  3. Hi. I had to mesh a component. I cut the solid in some parts and I meshed one of them with tetra elements (as you can see in the photo) because I wasn't able to mesh it using exa elements. I meshed the remaining parts with exa elements. Does it make any sense to mesh some parts with tetra and other ones with exa? Should I have meshed the whole component with tetra elements? Thank you.
  4. Hi Prakash, I corrected the penetration there was in my model. I used for both the bullet and the plate the Johnson-Cook material. The plate has a thicnkess of 0.5mm with: plasticty yield stress of 235 MPa; plasticty maximum stress of 360 MPa Due to the small thickness, I thought the bullet would pierce the plate. On the contrary, I have this strange behaviour as you can see looking at the pictures I have attached (displacement in millimeters). (This is https://www.dropbox.com/s/36ic9m7dmqc34vv/proiettile_06.hm?dl=0 the file .hm and this the file .h3d https://www.dropbox.com/s/fozixsq1kptudwq/proiettile_06.h3d?dl=0 )
  5. Hi Chait. Actually after 24 characters the temperature value starts. How did you know that (about the 24 characters)? Because I have not been able to find it.
  6. Hi. I have applied a temperature of 35 °C (through the panel Analysis-->Temperatures) on some of the nodes of my model. When I open the file .fem the id of the node is right next to the value of the temperature. How could one understand what the value of the temperature is just by looking at the file .fem? He or she could say, in my opinion, that the temperature is 5, or 35, or 335... TEMP 3 237335.0 TEMP 3 237835.0
  7. Hi. I had the same error of felipeds. In the interface panel I would select as master a component which was solid (not shell). Since master wants only surface, I fixed the problem in this way: first of all, inside the panel "entity set" I selected the component using as card image SURF_EXT; then, inside the panel "interface," I chose as master the set I previously created. And it worked. Is this procedure correct?
  8. Hi. I have to mesh a component with shell elements. If this component has a thickness of 5mm, what is the lowest element size underneath of which I can't go? Thank you.
  9. Equally, if I want a force with an magnitude less than 55 000 N, setting NINC=1 as Mario suggested, the analysis converges.
  10. Hi. I have been able to make the two analysis run. I used a property with card image PCONT and inside NLPARM I set the value as: NINC=10 MAXITER=25 CONV=UPW EPSU, EPSP, EPSW as default. To make the analysis run I increased the magnitude of the force. As a result of this, in one of the analysis if the magnitude of the force is <54000N the analysis doesn't converge. If the magnitude is >54000N, the analysis converge.
  11. H is the convective heat transfer coefficient: W/m2 C
  12. Hi Prakash. 99.98%. How is that possible and how can I fix this problem?
  13. Hi. I reduced the force by 10% (from 24N to 21.6N) to match the LOAD STEP 0.9 which was convergent. With this new value of the force however, LOAD STEP 0.9 was convergent, while LAOD STEP 1 wasn't. Then, since the EXPERTNL was activated, the LOADSTEP 0.95 was calculated. The bottom line is: LAOD STEP 0.9998 was convergent LOAD STEP 1.0000 was NOT convergent. (Now I no longer have the problem with the disk space since the error is merely: *** ERROR # 941 *** NON-CONVERGENT NONLINEAR ITERATIONS FOR SUBCASE 1.) Here's the final steps (from LOAD STEP 0.8 onwards):
  14. Hi Prakash, I am asked in this exercise to verify whether or not the bullet penetrates the plate. If a penetration occurs, I would say that the bullet ultimately penetrates. However, it is not normal that the analysis does not run.
  15. However, I have fixed the problem in another way. I opened the file.fem with an editor (Notepad) and I wrote in at the certain point this line: $ PARAM,EXPERTNL,CNTSTB $$ And actually it worked finally. On the other hand, since I had the same problem (non-convergent analysis) with another model, I tried to insert again PARAM,EXPERTNL,CNTSTB. This time it didn't work: LOAD STEP 0.1, 0.2, 0.3 ..., 0.9 were convergent, while LOAD STEP 1.0 wasn't. Here's the file: https://www.dropbox.com/s/zl54bn18nfpqs4d/supporto_09.hm?dl=0
  16. Hi Prakash, I have tried activating only EXPERTNL and not CNTNLSUB, but it still doesn't converge.
  17. Hi Prakash, I have sent you the file.
  18. Hi Prakash I'm using Hypermesh 12.0. Inside Control cards-->PARAM I have between many options EXPERTNL and CNTNLSUB. Inside EXPERTNL, I can only choose between YES and NO. The same thing for CNTNLSUB. What am I going to do?
  19. Hi Prakash, obviously the file you shared with me works. However, I tried activating the cards EXPERTNL and CNTNLSUB and I also tried setting in the NLPARM card NINC=25. However, It doesn't converge. What are the changes you made?
  20. Thank you Prakash, I will try and let you know.
  21. Hi Prakash thank you for answering. I have tried including that card but it still doesn't work.
  22. Hi. I get the same error using Radioss to simulate the impact of a bullet against a wall: ZERO OR NEGATIVE VOLUME FOR 3D-ELEMENT ID= but I don't understant how to fix it. Could you somehow help me out? This is the model https://www.dropbox.com/s/k5vct1x7cfcqtwx/proiettile_02.hm?dl=0 Thank you.
  23. Hi. I have come across the same error and I have solved the problem in the following way: first of all, I created a midsurface on the component named "comp_name" with id 33 (bear in mind this number 33). Hence, I got a new component named "Middle Surface" and I created the mesh on the component "Middle surface". Once I would run the analysis, I would get the error ERROR id : 178 ** ERROR IN PART (PROPERTY) IN PART NB 33 I tried to delete the component with the id 33 named "comp_name" and the analysis worked. The question is: why?
  24. Hi! Could you tell me what the meaning is of that substitution and why? I don't understant what the error is. Thank you.
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