DISP

User subroutine to specify prescribed boundary conditions.

User subroutine DISP:

  • can be used to define the magnitudes of prescribed boundary conditions or connector motions;

  • requires incremental values to be defined for prescribed rotation boundary conditions;

  • is called for all degrees of freedom listed in a user-subroutine-defined boundary condition or connector motion definition;

  • redefines any magnitudes that may be specified (and possibly modified by an amplitude) as part of the associated boundary condition or connector motion definition; and

  • ignores the specified type, if any, of the associated boundary condition or connector motion definition.

The following topics are discussed:

Related Topics
In Other Guides
Boundary conditions in Abaqus/Standard and Abaqus/Explicit
Connector actuation
*BOUNDARY
*CONNECTOR MOTION
Riser dynamics
DISP
Boundary conditions

ProductsAbaqus/Standard

User subroutine interface

      SUBROUTINE  DISP(U,KSTEP,KINC,TIME,NODE,NOEL,JDOF,COORDS)
C
      INCLUDE 'ABA_PARAM.INC'
C
      DIMENSION U(3),TIME(3),COORDS(3)
C


      user coding to define U


      RETURN
      END

Variables to be defined

U(1)

All variable types except rotation: the total value of the prescribed variable at this point. The variable may be displacement, pore pressure, temperature, etc., depending on the degree of freedom constrained. U(1) will be passed into the user subroutine as the value defined by any magnitude and/or amplitude specification for the boundary condition or connector motion.

Rotation variable type: the incremental value of the prescribed rotation at this point. The time increment, passed into the user subroutine through TIME(3), should be used to calculate the incremental value. In addition, U(1) will be passed into user subroutine DISP as the value defined by any magnitude or amplitude specification for the boundary condition.

If the analysis procedure requires that the time derivatives of prescribed variables be defined (for example, in a dynamic analysis the velocity and acceleration, as well as the value of the variable, are needed), d⁢u/d⁢t must be given in U(2) and d2⁢u/d⁢t2 in U(3). The total value of the variable (incremental value in the case of rotation) and its time derivatives must be given in user subroutine DISP, regardless of the type of boundary condition or connector motion.

Variables passed in for information

KSTEP

Step number.

KINC

Increment number.

TIME(1)

Current value of step time.

TIME(2)

Current value of total time.

TIME(3)

Current value of time increment.

NODE

Node number. This variable cannot be used if user subroutine DISP is used to prescribe connector motions.

NOEL

Element number. This variable cannot be used if user subroutine DISP is used to prescribe boundary conditions.

JDOF

Degree of freedom.

COORDS

An array containing the current coordinates of this point. These are the coordinates at the end of the prior increment if geometric nonlinearity is accounted for during the step (see Defining an analysis); otherwise, the array contains the original coordinates of the node. This array cannot be used if user subroutine DISP is used to prescribe connector motions.