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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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Found 11 results

  1. Dear sir, I want to analyse a model in radioss implicit which was ran in abaqus for vertical loading (non linear static problem with contacts), what are the basic implicit cards i should use to perfrom non linear implicit analysis (with vertical loading of a plate on roof structure and type 7 contacts , elastic - plastic material also) in radioss and compare the results with abaqus. Is there any tutorial which have executed the run in radioss using implicit cards. Thank you.
  2. http://www.altairhyperworks.com/training/new_feature_videos/14/videos/OS/fast_cont/fast_cont.htm
  3. LGDISP with PCOMP property

    Hello, I tried to run a job containing PCOMP and a hyperelastic solid modelized with MATHE card. I use a NLSTAT analysis. The run is ok in small displacement but when I use LGDISP I got the following error : *** FATAL ERROR # 3215 *** PCOMP in conjunction with PARAM, LGDISP is not supported. How can I do to perform large displacement analysis with PCOMP and hyperelastic components ? Thank you
  4. Hello, I am performing a large displacement nonlinear quasi-static analysis of a steel coupon under cyclic loading. I am applying displacement cycles using TLOAD1 and DLOAD, so that I can apply the entire loading protocol in a single subcase (cyclicing between 0.75 mm and 0). I would like to control the loading increment so that I have a smooth force-deformation hysteresis curve, but no matter what I try, the loading increment seems to increase beyond what I specified with NINC in NLPARM. For example, I have specified NINC=1000 (so that the increment should be 0.001), but in total my entire analysis has only about 150 increments. I have EXPERTNL turned off, and if I also turn off LGDISP, everything works fine, but once I turn LGDISP on, the increment seems to be automatically determined. Please advise! See attached for my model. Thank you, Justin Coupon4B_largedef.hm
  5. Is there a way to write out results for each time step when using the implicit solver for NLSTAT in Optistruct? Or, should I convert the model to BLOCK and run it with the RADIOSS explicit solver?
  6. Brake squeal analysis

    Hello, I'm trying to make a complex eigenvalue analysis with a non linear quasi-static as preload for a brake model. The aim of this work is to determinate unstable modes and to study squeal phenomenon. Using the full version with solvers patch 14.0.210 I succeed to launch the analysis, but the modes extracted are all stable. I tried lots of contact configurations: with the HM contact manager, using gap elements and using superelements with DMIG matrix, but Optistruct always gave the same results. The only way to have unstable modes is to use frictional elastic slip distance , but in this way the calculated modes have too low frequencies and too high dampings that is not correct (I have correct results for this model from someone who used another software). All the used values are appropriate to simulate squeal phenomenon and congruent compared to the respective units of measure. Does Optistruct allow to perform this kind of work?? If yes, could anyone help me, please?? Thanks Alberto
  7. nonlinear no converge

    Hi! I use math nonlinear and contact as shown below, set the curve material but solve nonlinear, the result does not converge, but the problem of linear static, then the result. So you could comment for me to solve this problem. M14 momen 30%.hm
  8. Hello! I am currently working on the analysis of a two piece wheel hub for a wheel hub drive. The model contains apart from the mesh a few contacts (some of them with a negative clearance for bolt pretension) and springs to modell the stiffness of the wheel bearings. My problem is that the analysis does converge pretty well but there are no results attached. I already tried to define several ouputs with different options but I never got results. If I just change the load step to "linear static" and run the analysis there are results. Did someone have the same problem already or does someone have an idea what could be my fault? I am working with HW 13 and Optistruct. Many thanks in advance! Regards, Max
  9. GAP with model 3D

    Hello, Could you give me one method to create element gap between the axis and the lug ? I use Optistruct with nonlinear gap analysis. The nodes of the lug and the axis have the same coordinate. Mesh with CPENTA and CHEXA. Thanks for help. Benoit
  10. Hi, Due to contacts in my model I wanna let my optimization run nonlinear. So far the linear analysis and optimization works. To let the analysis and optimization run nonlinear I created a load collector with the card image NLPARM. Additionally I created a non-linear quasi-static loadstep. The nonlinear analysis gives me results where as the optimization does not give any result even though I can let the optimization run without any error. Here I'm uploading a very simplified model that is compatible to the HyperWorks student edition. The contacts are not implemented yet. But there should be contact between the green, the yellow and the blue component. Maybe someone can tell me by which criteria I have to decide if the contact partner is master or slave. I'd be glad to get any advice how I can set up a nonlinear optimization with contacts in Optistruct. My question is: which steps do I have to carry out to turn a linear into a nonlinear optimization. Unfortunately I couldn't find that much information about it. Felix P.S. The model shows a medical implant for connecting bones. Maybe someone is wondering what it is Impl-Mandible-Fib-4S-Uebergang_vernetzt_1_temp13_Federn.zip
  11. Preloaded modal analysis

    Hello everyone, I would like to ask for an advice in solving a modal problem on a preloaded structure. I know that this is easily attainable with linear statics using STATSUB card, but I would like to find normal modes of a structure after non-linear static analysis (with contacts). Is it possible to run this sequence of analyses in OptiStruct: nonlinear statics --> normal modes? If not, would you have any suggestions how to do this? Best regards, Jakub