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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. Missing "NORMAL TERMINATION" in output file

    Hi, Type 18 interface is a coupling between a Lagrangian material and an ALE material, and for Type 18 interface the penetrations cannot be checked in HyperCrash or HyperMesh using penetration tools. Ignore these warnings, try running and we will review the results.
  2. MAT36

    Hi Zhaoying, For /MAT/LAW36 we provide post yield values in stress-strain curve, and the elastic portion of the material is defined by the Young modulus and Poisson’s ratio. By introducing strain rates we are controlling the change in strain (deformation) of a material with respect to time. Material plasticity curves can be given for up an arbitrary number of strain rates. Based on this strain rate the speed at which deformation of an object from its original shape occurs can be controlled.
  3. Leaf spring analysis

    Hi Pratik, Imposed displacement is what I meant which you have to provide to the bottom nodes.
  4. Leaf spring analysis

    Hi Pratik, We have discussed on a similar model. As told before for achieving this simulation you will have to run this simulation for a long time in RADIOSS, which is not recommended. Else,instead of concentrated load we will have to try with an imposed load (imposed displacement) type so that we can simulate it in a short time. The other option is to run with OptiStruct, where you can easily simulate this.
  5. Autocontact in Radioss

    Hi, Did you try fixing the initial penetrations using penetration check (Tools>>Penetration check) tool in HyperMesh?. The below post shows the same: For Type 7 interface use the recommended parameters: Istf=4 Igap=2 Fscale_Gap=0.8 INACTI=6 Gap_min= Fric = 0.1 Iform=2. Use a small Gapmin value for the contact.
  6. Autocontact in Radioss

    Hi, We don't have an AutoContact tool in RADIOSS similar to OptiStruct. I think you are trying to model a self interface. If so, then you can model the same using Type 7 interface.
  7. Pressing force for fitment analysis

    Hi Ganesh, Normally for axisymmetric we use 2D elements to model them. Use N2D3D = 1 for /ANALY card in the Starter file and ensure that the elements are defined in YZ plane and their normals have to be in the positive X-position. Let us also know the contacts you have used in this model. Also please share the .h3d of this simulation or atleast the .gif of the simulation.
  8. Pressing force for fitment analysis

    Hi Ganesh, For axisymmetric analysis there are many modelling restrictions and also all the normal results extracted are also not available for axisymmetric cases and so we normally don't recommend axisymmetric approach. For saving time, you can try varying the imposed load curve, ie instead of ramping in 0.1 you can ramp the load in .03 or .05. Also, you can introduce time step control (/DT/NODA/CST) so that you can save run time, but keep the mass error less than 5%.
  9. Pressing force for fitment analysis

    Hi Ganesh, Just let us know why you want to try with axisymmetric analysis as there are many restrictions on axisymmetric modeling for RADIOSS solver.
  10. Hi Abhinav, I'm attaching a snapshot showing normal unit consistency followed for FE analysis. Please go through and ensure the values are correct. The user has to ensure that the unit system followed is correct, there is no other ways to check the unit consistency. You can create a set for these elements and recall the same set in cross section panel. Resulting forces acting on these sections will be stored in the Time History file. and for that create an output block for this section. I recommend you to go through RD-T: 3540 Front Impact Bumper Model tutorial in Help menu where we have shown creating sections.

    Hi, This message is written for Interface TYPE2 using the search formulation for the closest master segment Isearch =2 (default value). This message is written to say that the slave node projects out of the closest master segment. You can ignore these warnings.

    Hi, In Help menu we have a lot of material on Hypermorph and we have a good number of tutorials also on the same. Please go through it. You can also go through https://altairuniversity.com/8212-morphing-using-morph-volumes/ which is a webinar on Hypermorph.
  13. Generating Enforced Velocities as a function of initial position

    Hi, Similar to analytical_field option we have equation option but it is not available for RADIOSS solver.
  14. Meaning of different strains in post-processing ?

    Hi, Plastic strain is the strain in which the deformed body does not return to its original shape after the removal of the applied force. The plastic strain value is calculated by the solver whereas the von Mises strain is calculated by the HyperView. HyperView calculates the von Mises strain from the six strain components. vonMises Strain = where: , , represent the principal strains as calculated above for a strain tensor. is the Poisson ratio set to a default value of 0.5.
  15. Generating Enforced Velocities as a function of initial position

    Hi, I don't think we have a script/option available for this function as of now. You have to manually create curves and assign to these nodes.
  16. Modify X axis with Node ID

    Hi, I'm attaching a document which shows creating a cross plot values along a specified node path. I think this may help you, please go through the same. Cross plot values along a specified node path.pdf
  17. NODE ID

    Hi Zhaoying, You can review the node group in HyperCrash but I don't think it's possible to see the node ids of the node group in HyperCrash. I suggest you to export the model from HyperCrash, manually open the model file (_0000.rad) in Textpad and review the node group where you can see all the node ids.
  18. Error

    Hi Kamalakarrao, The out files clearly shows many penetrations in your interfaces. Please depenetrate them and also clear any intersections if any are present. Please go through the below post which shows the tool for checking and clearing penetrations in the model:
  19. Leaf Spring Nonlinear Analysis using Radioss solver

    Hi Pratik, It is not possible to minimize the run time for this model. I have also ran for a long time for those results. You can solve this with implicit solver, and please use OptiStruct, where you can use NLSTAT with LGDISP to solve the same.
  20. Pressing force for fitment analysis

    Hi Ganesh, The animation looks fine. Create an output block for the rigid body, so to see the force you can plot the force on this RBODY in a particular direction using T01 file in HyperGraph.
  21. Element distortion @ contact interface

    Hi Karthic, |FNX| is the absolute value of normal force of the X-component of the contact force. It is the X-component of normal contact force applied to the master segment due to slave node. Please go through the Help menu on /TH/INTER where this is shown. Normally we check for the normal forces and resultant force.
  22. Hi Abhinav, Let me know the unis consistency you have followed in your model. Also share a pic of your stress- strain curve.
  23. Element distortion @ contact interface

    Hi Karthic, The above approach seems correct. Create an output block for contact and from the T01 file you can plot the normal resultant force for the contact (NF). Also you can generate animation files containing vectorial data for contact force using /ANIM/VECT/CONT
  24. SPH Inlets/Outlets Conditions

    Hi Sara, I checked the same file in HyperCrash but it shows only 2 components and it runs fine without any errors in RADIOSS. The same file is attached for your reference. test7_0000.rad
  25. Pressing force for fitment analysis

    Hi Ganesh, There are two options for interference fit. First you can simulate the physical press fit process in RADIOSS. Define contact between the two parts, constrain one part and apply an imposed displacement on the other part and simulation the physical press fit process. Second option is to use /INTER/TYPE24 contact and set INACTI=-1 which will apply forces to remove initial intersection caused by the press fit. The one limitation with INACTI=-1 is that it applies the force all at once and for large initial penetrations the force can be too large. To reduce the force you can use the STFAC option on /INTER/TYPE24. In the attached model, STFAC=0.25 seems to give reasonable results. Run the model with STFAC=1 (default) see the difference. I ran the attached model in RADIOSS version 2017.1 but 14.0.230 or 2017.0 should also be fine. Please review the attached. Interference_Fit_rad_s2_0000.rad Interference_Fit_rad_s2_0001.rad