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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. 

Adrien E

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  1. LGDISP with PCOMP property

    OK. Thank you for your reply.
  2. 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
  3. Thank you for your response Here is the .out file. I am thinking of changing the initial move limit to see if it can help. optim.out
  4. Hello, I am performing size optimization of a composite structure containing several zones. The objective is to minimize the mass while respecting displacement, composite failure and buckling constraints. I have twelve design variables representing different orientation thickness in different zones. Each design variable is linked to a discrete design value in order to account for a realistic ply thickness (multiple of my unitary ply thickness). My properties (PCOMP) link linearly one design variable to my components. I am running my job through a nonlinear quasi static optimization (NLSTAT) because of an elastomeric component in my model. The analysis is going well except that I can’t understand the way optistruct actualize my design variables: - -I set initially my design variables to my upper bound - At iteration 0 all constraints are satisfied - But then the solver only decreases all the design variables through the different iterations. This makes constraints violation more and more important. - At the last iteration all my design variables have reached my lower bound and the design is qualified unfeasible while all the constraints were satisfied at the beginning of the analysis. How does optistruct determine the design variable for the next iteration? I suppose there is an algorithm to converge toward an optimum solution but in my case it looks like my design variables just decrease from upper to lower bound. So I suppose there is a problem in the way I set my optimization problem. Do you have any clue of what that problem could be? Thank you very much for your help. Adrien