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  1. Hi, I had a question about this. I have a model with element size 1. When I optimize it and apply a minimal member size constraint of 1, 2 and 3, all 3 results are different. Can someone explain why since I understood that when I put 1 or 2, the minimal member size will be set to 3 and all 3 results should be the same. Thank you!
  2. Hi tinh, I think I found the problem! I created a mesh for the entire solid (before breaking it into smaller solids). Then I wanted to create a mesh in every solid separately but I just turned of the entire mesh and didn't remove it. Nothing was generated but the browers said: meshing...ready When I removed the complete mesh (that I hid). Every solid meshed without any problem! Thanks for your time anyway!
  3. Hi, It does create a component with a mesh. This mesh is on the intersection surface between 2 solids but ofcourse I dont want that, I want the whole solid to be meshed.
  4. Hi, The other components are things I added and earlier meshes I created. When I turn them on, I still dont see the mesh I wanted to. I think it is something else?
  5. Hello I imported a STEP-file to perform a topology optimization on an aircraft engine bracket. I edited the solid to create non-design regions (where my loads and constraints are) and design regions (that needs to be optimized). Without editing the geometry, I could mesh it without any problem using tetramesh: volume tetra. Now I wanted to redo the job and mesh the non-design regions in one component with a mesh and the design region in another component. But since I divided my geometry, I dont see the mesh when I perform it using tetramesh (2D mesh works). Sometimes is gives an error about free edges and sometimes nothing at all but I never see a mesh. I tried to cut me solid in other ways but still I can't mesh it. Anyone an idea how to solve this problem? ps: as you can see in the drawing, I can see the mesh in the non-design region of the upper holes but the other non-design regions (in white), don't show any mesh. When I try meshing the complete body, sometimes it only meshes the intersection face between the different solids.
  6. Hi Simon Thank you, this was already very helpfull! About the design and non-design spaces: I wanted to do that but I dont know how. The geometry is a loaded STEP-file and I cannot select just a part to be meshed as non-design region and another as design region since OptiStruct always selects the whole geometry. Any tips?
  7. Hi, I am optimizing an aircraft engine bracket (see image) and I would like to apply a (one horizontal and one vertical) load to the upper openings (indicated). It is a point load that should be applied to the middle of these openings since there is some kind of bolt carrying the load in real life. Applying a load to the centre of the opening and so 'air' obviously is impossible. Anyone any idea how to apply the load or linkt the centre of the opening to the structure? thank you!
  8. Hi I looked in the documentation but don't succes to make up my mind: Which are the solver methods used for topology optimization? I found that solvers used are -MFD -SQP -DUAL and DUAL2 -BIGOPT But in the beginning of the user manual Altair also talks about the optimality criteria method but in the manual I can not find anything about it. Which is the default solver for topology optimization and which others optimization algorithms can be used to solve a topology optimization problem?
  9. Hi, I was wondering how the creation of the stiffness matrix is defined. I don't mean how I implement it but I mean how OptiStruct knows how to generate a stiffness matrix. I was looking in the documentation for this but couldn't find it. Can someone help me? Thank you
  10. Hi, I am curious about the algoritms and codes used in OptiStruct and all the possibilities of the software. Does anyone know if there is some documentation about this and where I can find it?
  11. Hi, Thank you for your answer What I don't really understand is what the global stress constraint exactly does in topology optimization. In the above definition you mention it ignores local stresses that are too high but what is the point of using the stress constraint then? Your local stresses will still be too high. What is exactly meant by 'artificial stress concentrations' because as I understood the global stress constraint makes sure they are below the limit (declared in the global constraint) but I don't get what they exactly are.
  12. Hi, I know this question is already asked multiple times but I still haven't fully understood it. What is the exact difference when I define my stress constraint in the design variable of topology optimization or when I add it as a response and then a constraint of the optimization. When I add it in the design variable, without any other constraint it doesn't do anything (see attachment). Opposite to when I define it as a response and constraint. Then it does give results, although not very good ones. When I apply them both on one design, it gives a different result then when I only apply one of them 2. I do topology optimization of a hook with a minimum compliance and no other constraints or requirements. thank you!
  13. Hi, I am using HyperWorks 2019, student edition and am running a linear static analysis of a beam (topology optimization). I would like to display the displacements and stresses in the optimized structure. I found a tutuorial that could just go to a second page in hyperview where for each iteration the stresses and displacements could be visualized. I just have one tab that displays the densities (since in did a min compliance problem with volumefraction constraints). Does anyone have an idea about how to view the displacements? Thank you in advance!
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