What's New

This page describes recent changes in Abaqus user subroutines.

This page discusses:

R2022x FD01 (FP.2205)

User Subroutine UVARM

You can now use user subroutine UVARM to define user output variables in static linear perturbation procedures.

User subroutine UVARM allows you to access material point quantities and use them to define user output variables. This capability was previously available only with general analysis procedures. You can now use it with static perturbation procedures, including analyses with multiple load cases. If multiple load cases are specified in the static perturbation procedure, user subroutine UVARM is called once for each load case. Similar to the behavior with general analysis procedures, material point variables can be accessed from the user subroutine. However, access is limited to only those output variables for which perturbation values are available.

Benefits: This feature extends the capabilities of Abaqus/Standard.
For more information, see UVARM

User Subroutine VSDVINI

User subroutine VSDVINI is now available in Abaqus/Explicit to define initial solution-dependent state variable fields.
In Abaqus/Explicit you can now use user subroutine VSDVINI to define user-defined initial solution-dependent state variable fields at particular material points or shell section points. You can use and update solution-dependent state variables initialized in VSDVINI in other user subroutines called at particular material points (such as VUMAT and VUHARD) or shell section points (such as VUGENS).
Benefits: This feature extends the capabilities of Abaqus/Explicit.
For more information, see VSDVINI

R2022x GA

User Subroutine VUGENS

User subroutine VUGENS is particularly useful if the nonlinear behavior of the section involves geometric as well as material nonlinearity, such as may occur due to section collapse.
The subroutine provides the following information:
  • Section states at the start of the increment (section forces and moments, deformation gradient, solution-dependent state variables, temperature, and any predefined field variables).
  • Section states at the end of the increment (deformation gradients, curvature, temperature, and any predefined field variables.
  • Membrane strain increments.
  • Incremental curvature.
  • Time increment.

User subroutine VUGENS must update the forces, moments, and solution-dependent state variables to their values at the end of the increment; and it must provide the section stiffness matrix. You must program the complete section response in the user subroutine.

Benefits: In Abaqus/Explicit you can now define the shell section response in user subroutine VUGENS for the more general case where the section response may be nonlinear.
For more information, see VUGENS