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Simon Križnik

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Everything posted by Simon Križnik

  1. Hi, from https://altairuniversity.com/free-ebook-learn-dynamic-analysis-with-altair-optistruct/
  2. The nodes of the imported loads are equivalenced with those of the detailed model which are overlaying each other as a consequence of importing the free body loads. In the attached tutorial (HM-9010) this is done in step 10. I see no reason why it can't be done using displacement data.
  3. The icon used to start Hypermesh: I have it on my Windows taskbar, and it can also be found in the start menu, or search programs and files for "Hypermesh".
  4. Tied contacts are created automatically (along with materials, properties,...) when creating connectors with post script (see the end of the previously shared tutorial). Type 2 tied contact: VII_b_Interface Type 2 in RADIOSS - Altair University
  5. Hi, Radioss is a solver for highly non-linear problems under dynamic loadings by default. The analysis type is defined through control cards, for example: implicit/explicit method, dynamic/quasistatic, 3D/plane strain/axisymmetric analysis,... In Radioss the concept of loadsteps can be applied through multiple engine files in which the "subcases" can only be solved sequentially. For more info refer to https://altairuniversity.com/free-ebooks/free-ebook-crash-analysis-with-radioss-a-study-guide/
  6. Glad to help. Actually, location: elements have to be selected only on one side. The connection of adhesive brick elements is done through type 2 tied contact and is able to connect elements with different mesh sizes.
  7. I have explained how it is supposed to work. The issue is likely in your model and I can only guess without the model.
  8. Hi, Right click HyperMesh icon> Select Properties and change the "start in" location to another directory and try again.
  9. This is strange. Can you share the model file in .hm format?
  10. Hi, under Export options, you have set the Export to Custom. Click Select Entities which will take you to Entity State browser where you can define which entities are exported.
  11. Hi, it is possible- please refer to the following documents and links: https://insider.altairhyperworks.com/free-body-diagrams/ https://altairuniversity.com/learning-library/radioss-sub-modeling-cut-approach/ Free Body Diagrams.pdf Free Body Diagrams (FBD).pdf HM-9010__Free_Body_Diagram.pdf Subcase Specific Modeling.pdf
  12. Hi, control cards can be enabled or disabled: The same can be done by checking Status parameter of the control card (in the entity browser):
  13. Hi, Is there a reason to add complexity with frames and imposed displacements? The gravity load also on floor 2 and its rigid body nodes will result in a zero relative velocity with respect to the ball. An example of imposed velocity through frame can be found: drop_test_IMPVEL-edit_0000.rad
  14. Hi, I am able to create an area connector of type adhesive (contact) in Radioss (Hyperworks 2019.1 in Block format 140 user profile). The red rectangle indicates the connector realization failed for some reason (usually due to inappropriate tolerance).
  15. Hi, Unfortunately, no material law supports strain hardening exponent exceeding 1. As a workaround, try with material law 36 which is an isotropic elasto-plastic material using user-defined functions for the work-hardening portion of the stress-strain curve for different strain rates. While this material law does not have the convenience of describing the work hardening with only a few parameters, it allows describing the work hardening in greater detail with tabulated input.
  16. Hi, there were no Sol2SPH examples so I created it. In this example, the solid is switched to SPH upon element deletion (defined with energy failure model). Alternatively, the switch can be initiated by minimum timestep defined in DT/BRICK/DEL. For more information refer to the attached documents and link. http://blog.altair.com.cn/article.html?id=ac9r9ko3q0dnvst97iei1ogp6p8ah5xk Solid to SPH Option (Sol2SPH).pdf Sol2SPH Particle Behavior.pdf sol2sph_0000.rad
  17. Hi, modeling cable/pipe contact is computationally expensive (in particular the implicit method has convergence difficulties with stick-slip frictional phenomenon). Depending on the analysis objectives and assumptions, this system can be simplified as a cable pulley mechanism using: -Belt-Pulley system in Motionsolve -Spring TYPE12 in Radioss Create a Belt-Pulley Subsystem.pdf Spring TYPE12 - Pulley (_PROP_SPR_PUL).pdf
  18. Glad to help. In the model you shared the PSHELL property is applicable only to the two plates on either end. The lattice structure in between should be explicitly modeled with solid or beam elements. This model can not be simplified (homogenized) into a single layer of shell elements, due to shell elements being plane stress elements (no through-thickness stress). What T max value are you referring to? There is no such parameter in the PSHELL card. The thickness parameter assigns the missing third dimension to 2D (shell) elements.
  19. Hi, in the PSHELL property card the T parameter is the thickness and should be greater than 0. The thickness specified will be assigned to all shell elements in components referencing this property card. Property can also be assigned directly to elements by right-clicking the property in the browser and go for assign option. Alternatively, the nodal thickness can be assigned on CQUAD4 or CTRIA3 elements.
  20. Hi, Looks like the INIV/AXIS is not supported in Hypermesh. You can manually include the unsupported cards in the solver deck file with text editor. Attached is an example engine file from RD-E: 5501 Fan Blade Rotation Initialization fan_blade_initialize_0002.rad Tip: Ctrl+F to search for any keyword supported in HM (input in the upper right corner).
  21. Hi, exporting solver deck from Hypercrash will include names of parameters.
  22. Hi, you need to load the Vehicle Safety Tools preference file in HG (File > Load > select Vehicle Safety Tools > Load) Next, injury>HIC>Hic-Curve, chose the acceleration curve (shift+click), set windows length and finally click on apply. HIC_CURVE.wmv
  23. There are probably many methods to check the thickness assigned to elements. Display By Thickness: You can also use the visualization toolbar (View>toolbars>Visualization) for the 3D representation.
  24. Hi, what "geometry tab" are you referring to? Thickness is defined in the property that is assigned to the component.
  25. Hi, The engine file is not included (again). Use Engine File Assistant to easily define control cards. Engine file can be merged with starter on export: check the "Merge starter and engine file" option so the engine control cards defined will be in the starter file (_0000.rad). Open the _0000.rad file in Textpad or Notepad and ensure that engine control cards are present. It is not obvious how the model is not plausible- do you have experimental tests or previous experience? I can only think of the axial crushing might be too stiff. A geometric imperfection can be introduced with a /RANDOM nodal noise. There are intersections and penetrations in the contact interface which should be corrected. There are also 10 bad quality elements (negative volume).
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