Plastic Analysis

HamwicHamwic
I am investigating elastic plastic deformation.

The manual Section 14.1 Custom model definition provides a method of defining custom material properties.


The material is S275 steel.
Yield 275 N/mm^2
UTS 410 N/mm^2
E 210000 N/mm^2
23 % elongation to break

Is my interpretation below correct.


*SOLID SECTION,ELSET=Default,MATERIAL=MyMaterial
*MATERIAL,NAME=MyMaterial

*ELASTIC
210e9,0.3
*PLASTIC
275e6,0
410e6,0.23


Any help / advice appreciated.

Thank You

JN

Comments

  • SergioSergio
    Hamwik, those are engineering stress/strain values, you must transform to true stress/strain to use in CCX (true stress is a little higher than engineering stress). Also, the second point of your PLASTIC card is the ultimate stress/strain, but you must sustract the elastic strain portion from the ultimate strain (very few for steel, but for other can be significant).
  • HamwicHamwic
    Thank you for your comments.
    I am quite comfortable with elastic analysis but I have a lot to learn about plastic analysis.

    Can you suggest any reading material which may assist with the basics.

    Thank you.
  • SteveMeltonSteveMelton
    agree, for plastic analysis always use true stress/strain
  • HamwicHamwic
    Sergio / Steve

    Thank you for the pointers. I have it sorted now.

    Jim
  • SergioSergio
    Another trick is to add an extra point at very large strain (100% strain and compute the stress for this point to keep the tangent modulus constant) in order to help to converge in case of having a very small high plastic strain hot spot in your model. Obvioulsy you must take care that strains/stress values over the ultimate values cannot be taken in count.
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