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    • Rahul Ponginan

      Please click here for a short but important announcement   03/26/17

      Dear Users Our Commercial and Academic users around the world can use these same forums here as before i.e. the Altair Support Forum , Commercial users from India with solver queries can go to the Solver Forum for India Commercial Users , Academic Users from India and AOC India Participants are requested to go to the Forum for India Academic Users and AOC India Participants , We will be tending to all queries in all the forums promptly as before, thank you for your understanding. 


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About francois.B

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  1. Absolute Max Principal

    okay thank you a lot !
  2. Absolute Max Principal

    Maybe I should express myself better, I'm trying to obtain the RMS value for Absolute Max Principal Stress, in a .peak file. Regards.
  3. Random Fatigue Analysis

    Okay Thank you a lot ! Please ask me if you need anything else.
  4. Absolute Max Principal

    hello guys, i'm trying to obtain the Absolute MAx principal for my elements (not grids) in a .peak file, in order to have also the number of 0 crossing corresponding to these stress. Is it possible and if yes, how to do you obtain it? I know how to obtain some output but couldn't find this specific output. Below is an example of what I could obtain:
  5. Random Fatigue Analysis

    Hi, Please forgive me I'm kind of new to this and I don't really know how to be sure to look at equivalent PSD stress. here are My files, please tell me if anything is correct. By the way I did one different subcase for direction. NB : I limited the study to one element, ID = 14 (the one taking most damage according to Optistruct). PLAQUE_T.fem RUN_PLAQUE_T_ELEM_14.fem RUN_PLAQUE_T_ELEM_14.peak RUN_PLAQUE_T_MODAL.1.eigv SET_ETUDE.fem
  6. Random Fatigue Analysis

    Hello guys, I'm trying to do a Random fatigue analysis thanks to Optistruct. So first of all, I know that 2017 version has its own module which does this kind of analysis, and I already did it. I'm now trying to compare Optistruct results with a VBA code I did. So here are the step I did: - FRF and Random Subcases (with RANDPS, TABLED1 etc) - I ask for STRESS PSDF .Peak files for X to Z1, X to Z2, Y to Z1, Y to Z2, XY to Z1 and XY to Z2 Here, I can already see the number of positive crossing (which allow me to calculate life). First Question, do I have to divide this number by 2PI? My second question is, is it okay to create a derivated results on Hyperview, which does : RMS VELOCITY / (2*PI RMS DISPLACEMENT) in order to obtain the number of positive zero crossing directly on HyperView? This whole zero crossing things is kind of getting me crazy, a lot of people use it but I do'nt really understand how it works. (By the way, I can give you the files I have on my simple model if it is needed) Thanks for your answers!
  7. Stress extraction problem

    Hi Prakash Pagadala, Thank you for your time, waiting for your answer. Best regards
  8. Stress extraction problem

    Hi, We are using OptiStruct as solver.
  9. Stress extraction problem

    Hello guys, I'm writing to you today because I encounter a weird problem with HyperView. So here is the case. I'm an intern in a French company dealing with automotive and aeroplanes, and I have to develop a tool in order to calculate damages. Here is where I'm stuck, I have to compare RMS stress given by the old tool with the RMS stress given by the new tool I developped. In order to do that, I isolated a weld of my structure with a set I created on Hypermesh. I'll take the longitudinal case but I have the same problems in transversal and vertical ones. So for both case (old tool and new tool), I extract the RMS stress this way: - Result Type: RMS STRESS - Layers : Max - Resolved in: Global System (proj: none) - Averaging method: None Once I configured that (for XX, YY and ZZ stress), I query the stress and export it in a CSV file. A quick comparison of the results has been made for 9 elements (on 106) but as I told before I have the same problem on majority of them. As you can see, It seems that the coordinates system has been change during the extraction or even wehn I plotted it, but we can see that the stresses are really close but not in the good axis (for example element 65942). And for some elements, the stress are good (for example element 65637). How can I be sure that I'm extracting the stress in the same coordinate system? I do'nt really understand why I do have this problem because the extraction process was exactly the same. The results from the fist tool are obtained with a xml file which also give us the PSD. So we used the PSD and verified, with matematical formula, if the RMS stress was good after calculation and the answer is Yes. So it seems that the problem comes from the second tool, for which the results are obtained with OP2 file. If you need any other informations don't hesitate. thank you for your answer. Francois.B