Search the Community
Showing results for tags 'desvar'.
Found 4 results
Hi, I am working on a structural optimization of a model containing more then one PSHELL and PCOMPP properties. I am experiencing some issues with the sized model generated after the free-size optimization (*_sizing.fem) as output requested by the FSTOSZ line (OUTPUT,FSTOSZ,YES,4). I do not have any problem with the composite laminates but I have an unexpected behavior with the PSHELL components in the sized model generated. I try to explain the issue below with an example in brackets. If I have more then one PSHELL defined in the initial model (e.g., the PSHELL properties 2 and 3), I expect to have 4 times the number of PSHELL of the initial model in the new one (e.g, 2100, 2200, 2300, 2400, 3100, 3200, 3300, 3400) assigned to respective components (e.g., 2100->2400 assigned to components with initial property 2, and 3100->3400 assigned to components with initial property 3). The problem is that, in the new sized model generated, only 4 of these PSHELLs (e.g., 2100->2400) are assigned to components of the model and all the others are defined but not assigned (e.g., 3100->3400). Furthermore, the 4 properties considered (e.g, 2100->2400) are assigned to the entire designable space, also to components where I would have expected different properties (e.g., PSHELLs 2100->2400 are also applied to components with property 3 in the initial model, where I expect the 3100->3400 to be). This creates even more difficulties if the number of PSHELLs involved increases, because it becomes impossible to reproduce properly the optimized thickness distribution in the sized model with only 4 properties. I hope the description of the problem is clear enough. I am wondering if I miss something in the definition of the optimization problem or this is a known behavior for Optistruct. I would greatly appreciate any suggestion/information concerning this problem. Thank you in advance, Alessandro
Hi, I'm doing a DSYS type optimization and I inserted some parameters in the "desvar" part, and I'm not able to identify the values of these optimized parameters in the hyperview. Can someone help me??
Hi, After doing the HyperMesh morphing tutorials and the Optistruct shape optimization tutorials, I created a shape optimization file on my own. It consists of a cylindrical cantilever which is loaded sideways at the free end. The goal is to find an optimized cross section. The inner part remains unchanged, for the outer part (connected using equivalence) three different shapes are defined (elliptical morphing along x, along y and circular stretching). When minimizing the volume of the cantilever while limiting the stress in z-direction, the expected elliptical cross section results and the optimization constraint is fulfilled: Shape_opt_stress_constr.hm When limiting the displacement in load direction at the end of the cantilever, the cross section shrinks to a circle of minimum diameter and the displacement is much larger than the specified 0.15. Shape_opt_disp_constr.hm Isn't it possible to use displacement dconstraints for shape optimization? The solver (Optistruct) doesn't recognise the constraint violation and minimizes the volume to the extreme, leading to very high displacements. Thanks in advance for any inputs.
Hello! I have a problem and I haven't solved it for few days already. There is a rectangular composite plate and it is necessary to optimize thickness of the each ply to reach minimum mass and acceptable stiffness. Besides the thickness of each ply must to be multiple of the certain number. But a freesize optimisation with a composite optimisation result to the laminate with plies of different forms and each ply has inconstant thickness. I tried a lot of different ways, but it didn't help. For example, increasing of MINDIM is confined by some average dimension, and inspite of defined TMANUF of plies and PLYMAN of desvar the thickness is not multiple of the number. Can anybody help me? Best regards