Issues with von Mises Stress and von Mises Strain and Plastic Strain Values

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

I have simulated incremental sheet forming process in Hyperworks software and now I am analyzing the results.

1. The issue is that the undeformed portion of the sheet is also showing significant amount of von Mises stress and strain values. Which is absolutely impossible. How come the center undeformed portion of the component is experiencing effective stress and strain. However, there is no plastic strain in that area. Kindly, go through the attached images.

2. Secondly, Plastic strain distribution is correct but it does not sink with the von Mises strain results. What is the difference between the two.

3. Is the values of von Mises strain are in absolute terms or in percentage?

 

<?xml version="1.0" encoding="UTF-8"?>max vm stress.png

<?xml version="1.0" encoding="UTF-8"?>max von mises strain.png

<?xml version="1.0" encoding="UTF-8"?>plastic strain 4.png

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited February 2018

    Which version of HyperWorks you are using for analysis and post processing?I can only see the magnitude but no information about extracted output.

    It would be nice if you can share more information.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    I am using Hyperworks 12.0 version. I am attaching the screen shot of the full screen so that you can have more idea about the chosen options.

     

    Thanks

    <?xml version="1.0" encoding="UTF-8"?>Plastic Strain.PNG

    <?xml version="1.0" encoding="UTF-8"?>V Strain.PNG

    <?xml version="1.0" encoding="UTF-8"?>V stress.PNG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    There is one more issue:

    When I am forming the cone, irrespective of the forming depth after Time Step =4.00, the tool movement causes wrinkling in the component wall. However, provided tool path is rechecked and is correct.

    Whereas, even before I have formed the cone geometry up to the height of 50 mm and no wrinkling occurred at that time.

     

    I have checked the provided time also, but it is also correctly provided.

    Attaching the screen shot of wrinkled component.

     

    Thanks and Reply ASAP.

     

     

    <?xml version="1.0" encoding="UTF-8"?>Pyramid.PNG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    HI,

     

    stresses and strains have to be looked after springback analysis. the stress results after forming are high and unrealistic. Sprinback resets the stress.

     

    Regarding wrinkles, I will update you soon. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    Dear Prakash

     

    How to include spring back in the forming operation which we are simulating.

     

    Regarding wrinkling:

    kindly, share the address where I can share the hyperworks model (.hm) file.

     

    Thanks 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    Hi,

     

    Please use the file transfer link in my signature to share the model file

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    I have shared the files. kindly check.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    Got it, thank you :)/emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20'> 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2018

    Hi @PARNIKA SHRIVASTAVA

     

    Do you have access to HW 2017?

     

    If yes, can you try in latest instead of HW 12.0?

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