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Everything posted by Vrushang

  1. For your reference, Please refer this PAPER. 1. This paper gives you the comparison between different dynamic sub structuring models with respect to it's experimental prediction. https://orbi.ulg.ac.be/bitstream/2268/192786/1/273_roe.pdf 2. This paper gives idea about the accuracy required to get good results for stresses. http://web.mit.edu/kjb/www/Principal_Publications/Component_mode_synthesis_with_subspace_iterations_for_controlled_accuracy_of_frequency_and_mode_shape_solutions.pdf Have a Nice Day...
  2. Hi @SKGPrashanth , If you directly connect shell elements and 3d elements by rigid elements, you may get an error because 2d shell elements have 6 Degrees of freedom and 3d solid elements have 3 degrees of freedom, because of this reason if you extract the face of the 3d elements then this face elements are directly connected with the 3d solid elements and compensate that 6 degrees of freedom. You can give negligible thickness to that face elements ex: 0.01 mm and PSHELL as a property with any dummy material. (By default AUTOSPC card is ON, that remove this 3 extra degree of freedom of shell when it is in contact with solid, but in general it is not recommended to connect solid and shell elements directly by rigid elements. It may leads you to in correct behavior of your system). Regarding the equivalence of the nodes, it simply means your outer surface of the tube is directly connected with inner surface elements faces of the brackets and you don't get any friction effect. Another problem is that your original dimension of the pipe may change (i don't know exact geometry but may be) that leads to incorrect distribution of the stresses and displacement. you can model pipe as 3d solid elements and create contact pair between them, that will also take in to consider the friction between the components. Regarding Best Approach, There is nothing like best approach in FEA. The only thing that matters is how well you capture the physics of your system. For the same system your model will change if you are interested to study it with respect to strength, with respect to vibration, with respect to multi-body dynamics, with respect to fatigue or other non-linear analysis. In your case, please describe the purpose of this analysis then i think i can help you to decide how to connect the two components. By the way, your mesh is really nice, can you please share with me the methodology that you adept to generate the mesh. Thank you... Have a Nice Day...
  3. Sir, can you share PDF file and model file for the same. I don't find this in my Tutorials directory. I am using v13.0.
  4. Can any one Guide me for, Tutorial or Steps for: set up different type of contact condition between two solid and run in optistruct. (fix condition between surface pairs) post processing contact analysis result in Hyperview.
  5. @Prakash Pagadala Thank you sir for help. I attached hm and fem file for this problem: when i run analysis, it gives me error, ERROR IN Analysis In .FEM file it write this lines for PBEAML properties: $$HMERROR: Only OS Solver Standard Sections are supported. OptiStruct gives this error: *** ERROR # 1479 *** in the input data: Incorrectly formatted numeric data in field 9. (If it is a character field, it should start with a letter.) ERROR IN Optimization setup When i try to create DIM2 as a size design variable from Optimization>size>generic Relationship i can not get the DIM2 option. (Image for this is attached as opti.png) If DIM2 is not possible with GUI, I can do that with TCL script. but is there any way to access this from GUI. fem.fem Normal_mode.hm tunnelingeffectfiles.zip
  6. Hi There, I think you can use solid thinking inspire for geometric cleanup.
  7. Is it possible to get the value of Lagrange coefficient (lambda) at the end of constrained optimization in optistruct? (in particularly size optimization) I want this values because it will give you important clue for solution of optimization problem. It is possible to fetch this values at the end of optimization in MATLAB, So may be there is some way to fetch this values from Optistruct as well.
  8. Can i choose Inner radius and outer radius as design variable for size optimization of a structure made up of 1D tube element ?
  9. I think if you convert your rigid body model into flexible one you might get what you want.
  10. Tank you @tinh for your instant reply. can you please elaborate more on curves, or give some external link for the same. Thank you.
  11. Hi sir/Madam, in constraints panel i do not find any option to select local coordinate, how can i constraint only one degree of freedom with respect to local coordinate system ? and what is use of curve option in constraint panel ? Thank you...
  12. You can use ELEM OFFSET option available in 3D panel, for more information use link given below. element offset video (http://www.altairuniversity.com/wp-content/uploads/2013/12/offset1.mp4)
  13. Hi There, i want to open and see information in .h3d file as i see in NASTRAN .f06 file but i can not open .H3D or .RES in any text editor. Can i see the results and summery of what done in optistruct ? The only way i know how to access it is by HYPERVIEW but i want to select set of natural frequency and paste it in to report, is it possible with hyperview to export result that i want?
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