About Bilinear Isotropic Hardening Plastic Model !

- April 27, 2021 at 9:35 am
  
  Van Toan Nguyen
  Subscriber
  
  Hi everyone,nWhen I input data, the yellows marks occur. What does it mean? Thank you so much.n n
- April 27, 2021 at 4:07 pm
  
  Ram Gopisetti
  Ansys Employee
  
  Have you defined the Density and Basic Elastic terms and ANSYS WORKBENCH only takes 7 rows of data in Bilinear Isotropic Hardening by default. So we have to be wise to choose those points so that the interpolation handled by the solver falls within those curves. For more information , you can look into APDL commands to define more points. nCheers, Ramnn
- April 27, 2021 at 4:14 pm
  
  Sheldon Imaoka
  Ansys Employee
  
  Hi ToanNguyen,In addition to the helpful comment provided by ram_gopisetti, I just wanted to add two additional points:If Tangent Modulus is highlighted in yellow, it may be that your tangent modulus entered at 20 degC is higher than your elastic modulus, which is not permitted since plasticity should cause softening of the material, not hardening of the material (compared to its elastic deformation).nAs ram_gopisetti noted, the bilinear isotropic hardening model is currently limited to 6 temperatures, so that is why the remaining temperature sets are highlighted in yellow. A workaround is to use the multilinear isotropic hardening model, which does not have such a limit. You will need to input 2 data points - the first is the yield point (with zero plastic strain). The second should be a 'large' value to provide the same effect as the tangent modulus specification in bilinear isotropic hardening, but note that you will input stress and plastic strain (not total strain).Regards,Sheldo