ttavio
Civil/Environmental
- May 28, 2020
- 5
I am trying to implement a creep model for saline rocks through a UMAT subroutine.
From other works, I understood that during the implementation the Jacobian DDSDDE is defined considering the elastic material. Done this, the increment of viscous deformation (delta_ev) is calculated and the elastic deformation (delta_el) is obtained, making delta_el = dstran- delta_ev. Finally the tension is calculated by making stress = stress + ddsdde * delta_el.
When applying the subroutine in a triaxial test I come across the following error "The select primary variable is not available in the current frame for any elements in the current display group". This error appears when I use maximum increments in the 1 h viscous steps. However, when I use smaller increments, this error disappears and the simulation occurs correctly.
How can I solve this problem?
From other works, I understood that during the implementation the Jacobian DDSDDE is defined considering the elastic material. Done this, the increment of viscous deformation (delta_ev) is calculated and the elastic deformation (delta_el) is obtained, making delta_el = dstran- delta_ev. Finally the tension is calculated by making stress = stress + ddsdde * delta_el.
When applying the subroutine in a triaxial test I come across the following error "The select primary variable is not available in the current frame for any elements in the current display group". This error appears when I use maximum increments in the 1 h viscous steps. However, when I use smaller increments, this error disappears and the simulation occurs correctly.
How can I solve this problem?