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Pranav Hari

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  1. Julio liked a post in a topic by Pranav Hari in Composite mechanical properties   
    Hello Julio
     
    Apart from the e-book "Practical Aspects of Finite Element Simulation"  please refer the composite e-book also which specializes on composite modelling https://altairuniversity.com/free-ebook-introduction-to-practical-aspects-of-composites/
     
    Also refer composite tutorials from online help 
  2. Wiz211 liked a post in a topic by Pranav Hari in I can't see the buttons on the HyperMesh User Interface   
    Hello Wiz211
     
    Also try deleting the settings file and try again
     
     
  3. Sherdil.Leo0 liked a post in a topic by Pranav Hari in Application of Ifric inside INTER/TYPE7   
    Hi Skill.Leo0
     
    This is explained in the Radioss reference guide and user guide. Please have a look
     

     
    You can provide Type 7 interface to contact setup between brake pads and brake disk. Refer the attached example also BRAKE2_0000.rad BRAKE2_0001.rad BRAKE2_0002.rad
  4. Pranav Hari liked a post in a topic by Pritish Shubham in Query regarding Error (ERR) percent during solving the problem   
    Dear Pranav 
       Thanks for giving me such a detailed insight on the queries I had put on ERR Percentage. Its great to know these things which can help me understand the outcome of analysis in much better way. 
     
    Thanks and regards
    Pritish
  5. Pritish Shubham liked a post in a topic by Pranav Hari in Query regarding Error (ERR) percent during solving the problem   
    Hi Pritish Shubham
     
     
    ERR signifies the Energy error percentage
     
    It doesn't mean the deviation from the result. Negative Energy Error represents energy dissipated from the system and this can be from many sources including plastic deformation and Hourglass energy. 
    Please check the hourglass energy of the model.Keep Isolid=24 and try running the simulation.
    If the components penetrate each other due to the loads applied the user need to define an interface/contact between them for achieving a realistic simulation. The master segment can be parts, elements, contact surface, node sets and similarly for slave the selection can be parts and node sets. Once these master slave sets are identified the algorithm will check these locations for potential penetration of a slave node through a master segment, and this check is done in every time step
     
    Negative Energy Error represents energy dissipated from the system and positive energy error means energy absorbed in the system
     
    4. What should be the ideal scenario of ERR  Values we should expect while running a solution?
     
    You should check hourglass energy and contact energy in your model. ideally (Hour glass energy + contact energy)/Total energy < 15%
     
    Also, check the Radioss explicit e-book( https://altairuniversity.com/free-ebooks-2/free-ebook-crash-analysis-with-radioss-a-study-guide/) Page 283 onwards
     
     
     
     
    Check this forum post also
     
  6. tinh liked a post in a topic by Pranav Hari in Element Birth and Death   
    Hi bhanutheja
     
    It is possible by using /ACTIV card. It describes the deactivation/activation of element groups
    Check Radioss reference guide for more details. In 2019 HM iform option was added to /ACTIV card where you can activate and deactivate the elements.
     

  7. Pranav Hari liked a post in a topic by Andy in Problem: Plastic strain results do not match with the Von Mises stress results.   
    Hi,
    With LAW2, Iflag=1 the UTS and strain at UTS are engineering strain values.    But the output by Radioss is true stress and strain.  If you look in the Radioss starter you can see the Iflag=0, a, b, n values that are calculated using your input. 
     
    JOHNSON COOK MODEL : YIELD STRESS . . . . . . . . . . . . .= 355.0000000000 ULTIMATE STRESS (UTS) . . . . . . . . .= 470.0000000000 STRAIN AT UTS (Ag). . . . . . . . . . .= 9.0000000000000E-02 YIELD COEFFICIENT A . . . . . . . . . .= 355.0000000000 YIELD COEFFICIENT B . . . . . . . . . .= 312.9879880695 YIELD COEFFICIENT N . . . . . . . . . .= 0.2806664576242 EPS-MAX . . . . . . . . . . . . . . . .= 0.2100000000000 SIG-MAX . . . . . . . . . . . . . . . .= 1.0000000000000E+30 ISO-KINEMATIC HARDENING FACTOR. . . . .= 0.000000000000  
    You can input the a, b, n value into the equation in the comments of LAW2.    Note this equation is true stress as a function of plastic strain and I have left off the temperature and strain rate terms.
     
    Or the pre-processor HyperCrash lets you plot a material when you use a, b, n in LAW2.
     

     
    Note that this is a plot of True stress versus true strain (not plastic strain). 
     
    Please check if your output makes better sense using these stress strain plots. 
     
    It is good that you are thinking about the results with respect to your material input to see if they make sense.  Not everyone does this but they should!
     
    Thanks,
    Andy
     
  8. tinh liked a post in a topic by Pranav Hari in Why Rigid bodies are all regrouped together when passing from Hypercrash to Hypermesh   
    Hi JM Desrosiers
     
    While importing it back to Hypermesh, uncheck the solver option as shown in the image below. It will be in the separate components then.
     

     
     
  9. Santhosh Ravichandran liked a post in a topic by Pranav Hari in Optistruct Steady State Heat transfer Analysis   
    Hi Santhosh Ravichandran
     
    Refer tutorial OST: 1085, 1095 from OptiSruct help and check whether it helps.
  10. Hyperman liked a post in a topic by Pranav Hari in Total strain energy of a component in Optistruct   
    Hi Joao
     
     
    you will get the result in the .h3D file. You can open it in HyperView and change the result type to strain energy
     

     
    Also, check this pdf document about strain energy summation
    Calculating The Part Total Strain Energy File.pdf
  11. Tejas J liked a post in a topic by Pranav Hari in BATCHMESH   
    Hi Tejas J
     
    Check the online help for basis documentations on batchmesh
     

     
    Also, check the tutorial 
    HM-3140: Batch Meshing
  12. yehoo liked a post in a topic by Pranav Hari in error 1253   
    Hi yehoo
     
    I can see from the .OUT file, that the gravity has zero value. Please update it
    Also, the shell elements are not assigned with PSHELL property. Check and ensure whether all the shell elements (quad4) are assigned with a PSHELL property.
     
    If the error still persists, please share the model file.
    You can use the secure transfer link if needed.
    https://ftin.india.altair.com:8443/filedrop/~Ma3TaE
     
  13. Subhu liked a post in a topic by Pranav Hari in Token for feature   
    Hi Subhu
     
     If licensed under HyperWorks Units, each invocation of SimSolid will draw 30 HWU
  14. Livil Lyle liked a post in a topic by Pranav Hari in Envelope some previously generated derived load steps.   
    Hi manurico
     
    Yes, it is possible.
     

     
  15. Dragon_heart liked a post in a topic by Pranav Hari in Rubber component meshing   
    Hi Dragon_heart
     
    You can check this video as well as the learning library for more documents on Hexa meshing.
     
    https://altairuniversity.com/learning-library/
     
     
     
     
    Thanks
  16. pohan liked a post in a topic by Pranav Hari in Radioss Error 784: Error in Table definition   
    Hi Madhura
     
    1. Right click on the model browser and click create a curve.
     

     
    2.  click "new" and create a new curve. Change the option to /Table/1
     
    .
     
    3. Close all other windows and select the curve you just created from the model browser. change the options as in the image below. click on data:Ifunc and enter the values in the popup dialogue box
         
     

     
    4. There will be 3 fields to define. Ifunc, Strain rate (Ai) and Temp (Bi).
    HM lists this as Ifunc, V(0), V(1).
     
    5. Now you can assign this curve from the material data: Table_ID
     

     
     
    Hope it is clear...
     
  17. rabi liked a post in a topic by Pranav Hari in the is mesh not enclosed   
    Hi rabi
     
    Try adjusting the tolerance in the equivalence panel. Please note that adjusting tolerance should not affect the remaining mesh at any points
    Or try 2D> replace and replace the nodes manually to give connectivity
     
     

  18. Pranav Hari liked a post in a topic by Hyperman in Is it normal that Radioss solver showing huge amount of time remaining to solve a problem.   
    Hi,
     
    in explicit method the timestep is affected by characteristic element length, stiffness and density. Please go through the timestep chapter in Free eBook: Crash Analysis With RADIOSS – A Study Guide. Also recommended is 2017 Radioss user guide starting from page 30.
     
    Timestep_Crash_Analysis_with_RADIOSS.pdf
     
    Review what is causing very low time step in the engine out file:
    •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. If some elements are distorting badly during simulation it will lead to very low time step and the run will terminate. In this case use small strain formulation (in the property card).
    •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. Check the interfaces defined in the model for any penetrations.
     
    https://altair-2.wistia.com/medias/osd349gz4k
     
    To reduce solving time use mass scaling (DT/NODA) or advanced mass scaling (AMS). Any targeted model for AMS application should run first in /DT/NODA/CST with a reasonable energy error (ERROR < +2%) and acceptable added mass (MAS.ER < 0.02) along its simulation time. A model unable to run with /DT/NODA/CST will not run with AMS either. Output the number of AMS iterations per cycle via /DT/AMS/Iflag - Iflag =2 may help to monitor convergence quality at no extra CPU cost.
    Maximum allowed iterations before the divergence stops is 1000. 75 to 100 iteration per cycle is a sign of a poor convergence 50 still may provide some speedup
    30 iterations or less is considered a good convergence.There should be only a few cycles where INTER is controlling the timestep. 
     
    Use Multi-Domain Technique if your model has different subdomains characterized by different mesh sizes and consequently very different minimal time step. 
     
    Additionally, you can use single precision (Radioss panel options: -sp) to speed up computation. 
    Run time remaining can increase during the run even if the timestep does not drop. This happens when available CPU power is used during the run for other tasks (use Windows task manager to check how much CPU is utilized).
     
    Negative Energy Error represents energy dissipated from the system and this can be from many sources including plastic deformation and Hourglass energy. 
    If you have included coefficient of friction then the energy error is due to coefficient of friction which is justified. If this amount of energy error is there when no coefficient of friction is defined, then it may be a case of penetration which is problematic. The combined energy error (contact + hourglass) should be less than 15% of the total energy. 
     
    Energy error.pdf
     
    The following contact settings are recommended for type 7:
    Istf=4
    Igap=2
    Fscale_Gap=0.8
    INACTI=6
    Gap_min=1
    Fric = 0.1
    Iform=2
     
    You can try increasing the Gapmin in your TYPE7 interface which will allow the contact to work sooner and prevent deep penetration. It is also possible to use  /DT/INTER/DEL in the engine file to release slave nodes from the interface when time step drops below the value given in this option /DT/INTER/DEL- however, if there are many nodes released during the run the results can be questionable.
  19. Rahul R liked a post in a topic by Pranav Hari in warning   
    Hi JIAYU SUN
     
    This is because the GeForce series of Nvidia is not officially recommended by HyperWorks. However, this warninig message only appear once. You can proceed further and you may experience some graphical issues in the future.
    HyperWorks_2017_Hardware_Recommendations_and_Certifications.pdf
  20. Laura27 liked a post in a topic by Pranav Hari in Installation Student Edition 2017   
    Hi Laura27
     
    When you click on this link, HyperWorks student edition package will be downloaded which has the above-mentioned features. 
    As you mentioned those aren't separate links but is a single link for HyperWorks student edition download.
     

     
    When the download is finished, install the software and use the altair_lic.dat file attached with the mail.
    Set the license file by creating an environment variable as described in the mail.
  21. forestis liked a post in a topic by Pranav Hari in Getting error: Graphics card not supported when viewing results in Hyperview   
    Hi forestis
     
    HyperWorks do support Nvidia graphics cards, but not the Geforce series. Nvidia Quadro series is officially recommended. The Quadro series is more geared towards CAD and graphics designs, while the GeForce line leans towards gaming.
    However, you can still work with the GeForce series. The thing is, you may face some graphical issues.
    Check the GPU recommendation of HyperWorks (pdf)
     
    Also, check this to see the difference between Geforce and Quadro series of Nvidia. You can understand which series is best suited for software/simulation/design application.
    https://www.quora.com/What-is-the-difference-between-Nvidia-Quadro-and-Geforce-How-each-of-them-perform-on-CAD-and-Gaming
     
    hyperworks_2018_hardware_recommendations_and_certifications (1).pdf
  22. Pranav Hari liked a post in a topic by Hyperman in Unable to generate Spot weld connection between Solid elements   
    Contact surfaces can also be used.
  23. MEIYARASU19 liked a post in a topic by Pranav Hari in Listing Loads   
    Hi karth
     
    In HyperView use the vector option, where you can view the magnitude and direction of displacement for selected nodes.
     

  24. Guy01 liked a post in a topic by Pranav Hari in Surface Edge Thickness   
    Hi Aerokid
     
    Press "O" from Hypermesh or go to preference and select graphics.
    Tick the option for thick 1D elements as shown below
     

     
     

  25. Pranav Hari liked a post in a topic by Hyperman in Cutting analysis OptiStruct/Radioss??   
    Hi,
     
    in addition to @Pranav Hari suggestions, it looks like the example you shared is a 2D plane strain analysis. It is computationally more efficient to run this type of analysis instead of 3D analysis.  Check the following topic for details:
     
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