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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. 

George P Johnson

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Everything posted by George P Johnson

  1. Hypergraph axis magnitude

    Hi, You can change the X parameter. Please refer the image attached.
  2. How do I create a template to extract responses for nodes in HyperGraph?

    Hi, Can you please elaborate on your query?. If you are looking for magnitude and phase response for each node in a text file, you need to create 17 output request for 17 nodes and 17 sets which contains each node with OPTI as format and form as BOTH.
  3. Volume Calculation

    Hi, The possible workaround is to export the deformed shape from HyperView and open the same in HyperMesh and recheck the volume. This link shows exporting a deformed shape from HyperView: https://www.youtube.com/watch?v=i_P5GBsUo3U
  4. Intersections and Penetrations

    Hi Ushay, It is always recommended to remove the intersections and penetrations before the run. These could result in weird behavior of the model. We have a tutorial in Help Menu which shows removing intersections and penetrations, HM-3320: Penetration.
  5. bugg in hm graphic area

    Hi Yukesh, Please click on Shaded Elements and Mesh Lines option in the toolbar and review. Also, from mask browser click on show for elements. Please try with these options.
  6. Difficulty finding correct time step

    Hi Brandon, Please review the engine out (_0001.out) file while running so that you can review the time step and can find what is causing the time step to drop. It can be due to an element, a node or an interface. •For an element, check the related material (especially its Young modulus and density in case of an elastic-plastic material; and its viscosity in case of a visco-elastic material). There must not be an error in the units system that this data is given in. Check the size of the element, since elemental length is proportional to time step. •For a node, check the characteristics of connected elements. If the node is on the master side or the slave side of an interface, this interface must be verified. •For an interface, the gap of the interface must be verified if some failure happens on the master or the slave side of the interface. These are the possible workarounds for time step drop.
  7. Difficulty finding correct time step

    Hi Brandon, Yes, lowering the Tmin in /DT/NODA/CST will reduce the mass error. Mass error of 38 percent is very high. Reduce the Tmin value and try running.
  8. RADIOSS solver stopping after starter run

    Hi Ajay, This seems like the RADIOSS solver is stopping after the starter run. Ensure the engine file (_0001.rad) is present, with the same file name as of the starter.
  9. plot graph in a restarted analysis

    Hi Guru, How much was the run time for the first run, that is in _0001.rad?. Also, please upload T02 file, plot and review the curve.
  10. plot graph in a restarted analysis

    Hi Guru, Choose the first time history file, that is T01 and plot. This will contain the whole time history data for the complete run.
  11. Energy Error

    Hi Pohan, The energy error percentage is the parameter that checks the energy conservation during each numerical cycle and it is computed by RADIOSS is a percentage. If the energy error is negative it means that some energy has been dissipated. If the error is positive there is an energy creation. If the positive energy error is high, the source of this energy has to be identified. Incompatible kinematic conditions can lead to such a situation. Normally, the energy error must be negative and decreasing (except for the first cycle ). The error should be less than 15% at the end of computation but if the model undergoes high plastic deformation the energy error can increase.
  12. Both kinetic energy and internal energy are not consistence!!

    Hi Nut, You are right, the time step value chosen should be an optimal one. As a general note, although increasing Tmin value increases the computational speed considerably, care must be taken to see that a bound is put on the percentage of mass increase. It should not change the physics of the problem i.e. mass increase is allowed for deformable bodies but if applied to rigid bodies then results will be different than the original model. Hence always the mass error created should be very less.
  13. Radioss material comment

    Hi Toan, In the solver window it is not possible. In the out file only you can review.
  14. Radioss material comment

    Hi, In such a case user can get the material information in the starter out file. Open the starter out (_0000.out) in Textpad where user can get the material details. RADIOSS writes these parameters default.
  15. Frictionless Contact

    Hi, In the interface card user can specify the type of Frictional Formulation and input the friction accordingly. If the user don't want to introduce friction leave these blank.
  16. measure distance

    Hi Toan, Did you try with hm_getdistance The format is hm_getdistance entity_type id1 id2 syst_id
  17. Difficulty finding correct time step

    Hi Brandon, Please review the results with this run time. Ensure the mass error is less than 5% (.05), due to the imposed time step, which is always a good practice.
  18. Both kinetic energy and internal energy are not consistence!!

    Hi Nut, If you are using Tmin as 0, that means no time step is imposed in the model and so no mass will be added in the model and the DM/M will remain zero. But in case if you want to impose a time step, which controls the model from dropping time step, mass will be added but the Tmin should be an optimum value that the mass added in the model should be less than 5% (.05).
  19. Radioss material comment

    Hi Toan, Can you be more clear on the query, that is which comment window?. From 2017 version, in the model browser user can view the material parameters and its options description in the entity editor.
  20. connectors

    Hi, Please find the tutorials. You can download the respective model files from https://altairuniversity.com/model-files-for-student-edition-users-accompaniment-to-the-tutorials-in-help/ HM-3000.pdf HM-3400.pdf HM-3410.pdf HM-3420.pdf HM-3430.pdf HM-4020.pdf
  21. Both kinetic energy and internal energy are not consistence!!

    Hi Nut, While imposing a time step the best practice is to have less than 5% added mass (0.05) which can be monitored in the engine out file (DM/M). The energy plot is a typical quasi static simulation plot. We have a similar kind of tutorial in Help Menu, RD-3530: Buckling of a Tube using Half Tube Mesh. I recommend you to refer the same.
  22. Difficulty finding correct time step

    Hi Brandon, Normally explicit analysis will range in 100-300 milliseconds, but this depends on the application. For crash analysis or bird strike analysis, it will last for hardly 50 milliseconds.
  23. Difficulty finding correct time step

    Hi Brandon, Which unit system are you following in this model?. Is it kg, mm, ms? The run time specified also seems high. I'm presuming that the unit system is kg, mm, ms and so, the total run time provided is 5000 ms, that is 5 seconds which is very high for explicit analysis. Please recheck the same.
  24. No 0001.rad is written during calculation

    Hi Guillaume, There is no need to rename, since both the starter and engine files are merged. You can directly run the file. To provide the run time, either open the _0000.rad file Textpad or Notepad and manually change the run time under /RUN. Please see the attached image. Else import the file in HyperMesh, change the run time and export again. Since you are a beginner I recommend you to practice a crash box tutorial which is available at https://altairuniversity.com/wp-content/uploads/2016/11/Crash_Box_1.pdf Also, you can get exposed to various analyses using Altair tools at https://altairuniversity.com/conceptual-design-of-a-3-wheeler-motorbike/
  25. No 0001.rad is written during calculation

    Hi Guillaume, Since you have checked "Merge starter and engine file" option, the engine control cards defined will be in the starter file (_0000.rad) itself and that's why engine file was not created separately. Open the _0000.rad file in Textpad or Notepad and ensure that engine control cards are present. If the control cards are present in the starter file you can run the same.
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