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      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 81 results

  1. Bolt position optimization

    Hi, I have a model of a plate with many holes that need to be fastened to a beam. I want to make an optimization with Hyperstudy to know where I need to put the bolts to have the minimum stress inside the plate. How can I define my model in Hypermesh, in which Hyperstudy will be able to create all the possible combinations of bolts position for a DOE ? Thank you, Benjamin
  2. Hello All, I created simple cylindrical shell with a hole at the center and i wanna make this shell stiffer by adding ribs on its surface thus i need to perform topography optimization in order to get ribs configuration and i did as you can see in attached picture. But after i added ribs(stiffeners) to base model and run it under the linear buckling loading , i came up with less critical load than i got from the model without any ribs so i am confused now how it could be possible. I picked objective is to minimize response which was "buckling" is there anyone knows what could be the correct objective to get correct ribs configuration? Aim is to make more stiffener structure under the linear buckling loading.
  3. Hello everyone, I am currently running some optimizations for a strucutural component, which I have to write an Essay about. While looking at the eigen modes Output, this question accured: What is the Unit displayed on the scale? It says Eigen Modes Magnitude, but does that mean the oscillation in Hz, the displacement in mm, no unit or another unit? I appreciate any help and hints!
  4. Hello, I am working on an optimization problem of a blade. One of my constraints will be centre of gravity. I would like to keep the cog at 1/4 of the chord. I am having trouble in understanding how to define the upper and lower limits of cg. Should they be the coordinates? If so on whicj plane and how can I define the reference point to find out what the coordinates are? Thank you, Muge
  5. flaecheopti_multiobjective.femHello, i was trying to make a multi-objective optimization by combining a "massfrac" and a "compliance" response in the dresp2 "function" card. Unfortunately I always get the following error message: A fatal error has been detected during input processing: *** ERROR # 557 *** DRESP2 3 is not referenced above the first SUBCASE. This type of response must be specified above the first SUBCASE. This error occurs in DESOBJ 3. I don't understand how I'm supposed to reference the dresp2 above the first subcase. The Hyperworks Help does not specify how to reference it above the subcase only that in some cases it is necessary. I tried to create the responses before creating the loadstep but that didn't solve it. I also tried to just cut+paste the objective section from the subcase information in the .fem-file infront of the loadstep section. But running the edited .fem-file from the command prompt didn't work either. Am I missing something here? The .fem-file is (hopefully) attached. Thanks for any helpful tip!
  6. Hello, I am running lattice optimization on certain shapes that I would like to 3D print. I was wondering if a separate tool or software is required/can be used to make the obtained lattice structure manufacturable? What would be the method for manufacturing the varying lattice densities? Thank you, Muge Candogan
  7. Non Linear Optimization with Pretension

    Hello All, I am running a Non Linear Optimization with the following load conditions: STEP-1 Assembly fit using PCONT clearance Pretension STEP-2 Temperature change from 23 degres to -40 degrees Non linear optistruct run was clear but when I run the model for optimization I get the following error: *** ERROR # 415 *** Static Subcase 2 has "STATSUB(PRETENS)" defined. Optimization with compliance cannot be performed. Any suggestions will be highly appreciated. Thanks Praveen
  8. Hi, So while reviewing the result of topology optimization in hyperview we have two different pages showing design history (densities) and the subcase result (displacement and stresses). How can i plot the contour value of stresses or displacement while at the same time showing the iso-value of densities (optimized shape)? Thanks! bayupu
  9. Error 789

    Dear community, I have a problem with the composite size optimization if I set a value for TMANUF for the plies. After the free-sizing, I use the sized model to perform a sizing optimization setting a specific manufacturable thickness for the plies involved (TMANUF). The solver is able to run the iteration zero, but it stops giving me the following error when iteration 1 starts. *** ERROR # 789 *** Invalid design properties w.r.t. the design variables were found. number of invalid property items = 6 This happens only if I set a value for TMANUF and also if I delete all the settings for maximum and minimum laminate thickness. Unfortunately, I cannot share the model I am working on. Any suggestion on the matter? Thanks in advance, Alessandro
  10. Dear Community, I find a problem in imposing minimum ply thickness constraint (PLYTHK) during free-size optimization. Whatever value I put in the DSIZE card as minimum ply thickness, this seems to be ignored by the solver and I get, in the resultant size model, plies with thickness lower than the value I specify. I have attached a simple model as example. In the example: Although I set 0.05mm as minimum ply thickness for all the plies, I get plies with lower thickness (e.g, ply 205200 is 0.02mm thick, ply 310300 is 0.0096mm thick, and so on...) in the sized resultant model. Has anybody found the same behaviour? and, has anybody found a solution? Thanks for the support, Alessandro plythk_issue_sizing.13.fem plythk_issue.hm
  11. optistruct

    when i do optimization of an automobile part , this part having more than 200 iteration in optimization result. how to reduce or minimize the iteration in optimization result.
  12. knuckle optimization

    Should I do optimization after model has passed linear analysis or it can be done from beginning? Bcoz when I am doing from beginning then stress distribution are non uniform and thus its removing too much of material
  13. Hello, I am trying to run topology optimization on rod elements. The optimization response would be buckling. I have two questions: 1) I am not clear about the upper and lower constraints for buckling response. Are they buckling load factors? What should I consider to define such constraint for buckling? 2) During the analysis and optimization, I am supposed to keep the length to diameter ratio greater than or equal to 10. How can I implement this as a constraint? Thank you in advance, Muge Candogan
  14. Different Lattice Types

    Hi, Does anyone know what is the difference between different lattice types( type 1, 2 , 3 and 4) in lattice optimization by Optistruct? And how can I get their properties after optimization? Thank you,
  15. Hi, I am doing topology optimization for a cantilever beam and I want to know the mass reduction after optimization. Does anyone know how to calculate the mass for optimized result. In lattice optimization , I can import the .fem file into hyperworks and calculate the mass. But for topology optimization, it didn't work. Is there anyway I can calculate the mass for topology optimized results. Thank you, Regards, Soraya
  16. @Deep we are reducing mass of pitman arm so my question is what is the difference between mass and mass fraction, volume and volume fraction??
  17. Hi, I am wondering that does the Optistruct is a mesh independent optimize solver? in other words, does the topo optimization result in Optistruct change with mesh refinement? I don't have time to make a model for verification so hopefully someone can help me on this. It should not have different pattern of topo optimization for finer elements if proper sensitivity filter used. Thanks,
  18. Optimization constraints

    Hello, I have tried running a topology optimization on a simply supported beam. I defined the objective as min. mass but did not introduce any stress or deformation constraints. And the optimization gave results. Is it possible to run a topology optimization without constraints? Then based on which parameter the software optimizes the structure, does it automatically introduce constraints by itself? Thank you, Muge Candogan
  19. Size Optimization of Stiffened Plate.

    Is there any tutorials available for Optimization of stiffened plate. In my case my design variable is size of the stiffener and keeping dimension of the plate as constant. And constraint is, max displacement of the plate should not go 1mm..
  20. I am attempting to optimize an imported geometry though I ran into several problems; - The mesh quality was apparently lacking (used the tetra mesh option to mesh create it), so I bypassed this check by using a control card. - Though point loads and contraints have been applied to the mesh, the output is only of a few iterations and too closely resembles the geometry to be called a viable optimization: reducing the upper bound of the optimization constraints does not appear to resolve this... As a side note, I would also like to know if it would be possible to implement moments onto the mesh. I have a general idea but I'm not entirely sure. I will attach supplementary files as soon as I am able. Thanks Edit: I would also like to mention my goal is to minimise compliance with a volumefraction or mass fraction as an optimization constraint. Edit2: Nevermind I solved my own problem.
  21. 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
  22. Lattice Optimization Confusion

    Hi there, I'm new to lattice optimization and confronted a curious problem. My test example is a cubic, with dimension 240mm*146mm*1000m for example, after state analysis, the max displacement is about 7.5mm. Then I did lattice optimization, set volume_fraction as constraint and Min_compliance(Max stiffness) as objective. I set the density as Design_variable, with range 0.01~1, as shown in pic attached. And I have two control cards to set optimization process. My three questions are: 1. What should I choose for "Config" for these two cards respectively? One just controls interation number and the other control lattice parameter? 2. When I set minimum of lattice radius value, for example10mm, it appears as the maximum radius value in the control card. Why does this happen? 3. Is it possible for me to have a lattice optimized structure having same stiffness(max disp) as the original solid one? And How? Is it possible to achieve it just by changing lattice radius? Great thanks!
  23. How to define ply percentage & balance constrained in HyperStudy? Following are definition from fem file. DCOMP 1 STACK 2 + PLYPCT 45 20 25 BYANG + PLYPCT 90 55 60 BYANG + PLYPCT 45 20 25 BYANG + BALANCE -45.0 45.0 BYANG I have created model in hm for 32 ply. In hyper stydy I am defining discrete design variable for ply direction which will take up values -45,0,45,90. But I am unable to add ply percentage & balance constraints in hyper study. 32_ply.fem
  24. DSHUFFLE card RANGE parameter

    Hi everyone, In the Optistruct 13.0 Reference guide, it says that in the DSHUFFLE card can be defined a RANGE parameter. However I can't find it in my software which is v13.0. Can anybody explain why? Thank you, Gonçalo
  25. Hello Friends, In my Optimization Inputs before I gave mass as constriant and I got new mass everytime in Responses Table. But now I Need volume also, for that I took one more volume Response and Volume constraint with lower bound Zero, so I can see what happen in upper bound. But it Shows nothing in Response Table. Please help... Thank you, Regards, Jay
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