DISP

This problem contains basic test cases for one or more Abaqus elements and features.

The following topics are discussed:

Elements tested
Features tested
Problem description
Results and discussion
Input files

ProductsAbaqus/Standard

Elements tested

T3D2

Features tested

User subroutine to provide prescribed nodal behavior (displacements, velocities, and accelerations).

Problem description

A straight section built with one-dimensional truss elements is used in a dynamic analysis. The model has boundary conditions prescribed at nodes 2, 3, and 4 (nodes TRUSS.3, TRUSS.5, and TRUSS.7 in the model defined in terms of an assembly of part instances) using user subroutine DISP, while at nodes 5, 6, and 7 (TRUSS.9, TRUSS.11, and TRUSS.13) the boundary conditions are prescribed using an amplitude definition. A displacement variation is specified at nodes 2 and 5 (TRUSS.3 and TRUSS.9), a velocity variation is specified at nodes 3 and 6 (TRUSS.5 and TRUSS.11), and an acceleration variation is specified at nodes 4 and 7 (TRUSS.7 and TRUSS.13). The variation prescribed is

f (x) = 1.5 \sin (.1 π t) + .5 \cos (.1 π t) .

For the variations specified using DISP, the appropriate derivatives and integrals have to be incorporated into the subroutine. For the amplitude specification Abaqus automatically performs the necessary differentiation and integration. Identical variations are specified in both methods such that the results should be identical.

Results and discussion

The responses of the nodal degrees of freedom can be plotted to show that user subroutine DISP is providing the same history as the amplitude description.

Input files

udispxxx.inp: Input file for this analysis.
udispxxx.f: User subroutine DISP used in udispxxx.inp.
udispxxx_part1.inp: Input file for this analysis with the model defined in terms of an assembly of part instances. This file refers to the user subroutine DISP that uses the utility routine GETPARTINFO.
udispxxx_part1.f: User subroutine DISP used in udispxxx_part1.inp (illustrates the use of the utility routine GETPARTINFO).
udispxxx_part2.inp: Input file for this analysis with the model defined in terms of an assembly of part instances. This file refers to the user subroutine DISP that uses the utility routine GETINTERNAL.
udispxxx_part2.f: User subroutine DISP used in udispxxx_part2.inp (illustrates the use of the utility routine GETINTERNAL).