USDFLD

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

This page discusses:

ProductsAbaqus/Standard

Elements tested

B21

CPE4

DC1D2

DC2D4

DS4

S4

S4R

Features tested

User subroutine to redefine field variables at a material point.

Problem description

This set of tests verifies that field variable values are properly transferred to a structure when the values are redefined at run time. In every instance an Abaqus material model with dependency on a solution variable (such as temperature or equivalent plastic strain) is implemented with field-variable dependence. The appropriate field values are computed at run-time based on solution values from the previous increment. Every user-defined field variable model is checked against the equivalent Abaqus material model.

The hypoelastic material model is chosen as the basis for nonlinear elastic behavior at small strains for both static and dynamic analyses. Since Abaqus does not provide dependence of the hypoelastic tangent modulus on field variables, it was implemented using an elastic material with the equivalent secant modulus.

Results and discussion

A very close match is obtained between the user field variable approach and the corresponding Abaqus model. Figure 1 shows how the hypoelastic models compare in a static analysis. Matches of a similar nature can be obtained for the other files by using the time-history plotting capability available in the Visualization module of Abaqus/CAE.

Since the field variable approach uses values from the previous increment, the solution should improve as the time increment decreases. This trend was observed throughout.

Input files

udfcd1hs.inp

Steady-state heat transfer analysis, DC1D2 elements.

udfcd1hs.f

User subroutine USDFLD used in udfcd1hs.inp.

udfcd1ht.inp

Transient heat transfer analysis, DC1D2 elements.

udfcd1ht.f

User subroutine USDFLD used in udfcd1ht.inp.

udfcd2hs.inp

Steady-state heat transfer analysis, DC2D4 elements.

udfcd2hs.f

User subroutine USDFLD used in udfcd2hs.inp.

udfcd2ht.inp

Transient heat transfer analysis, DC2D4 elements.

udfcd2ht.f

User subroutine USDFLD used in udfcd2ht.inp.

udfcdshs.inp

Steady-state heat transfer analysis, DS4 elements.

udfcdshs.f

User subroutine USDFLD used in udfcdshs.inp.

udfcdsht.inp

Transient heat transfer analysis, DS4 elements.

udfcdsht.f

User subroutine USDFLD used in udfcdsht.inp.

udfebxdx.inp

Dynamic analysis, elastic, B21 elements.

udfebxdx.f

User subroutine USDFLD used in udfebxdx.inp.

udfebxsx.inp

Static analysis, elastic, B21 elements.

udfebxsx.f

User subroutine USDFLD used in udfebxsx.inp.

udfecxdx.inp

Dynamic analysis, elastic, CPE4 elements.

udfecxdx.f

User subroutine USDFLD used in udfecxdx.inp.

udfecxsx.inp

Static analysis, elastic, CPE4 elements.

udfecxsx.f

User subroutine USDFLD used in udfecxsx.inp.

udfesxdx.inp

Dynamic analysis, elastic, S4R elements.

udfesxdx.f

User subroutine USDFLD used in udfesxdx.inp.

udfesxsx.inp

Static analysis, elastic, S4/S4R elements.

udfesxsx.f

User subroutine USDFLD used in udfesxsx.inp.

udfpbxsf.inp

Static analysis followed by frequency analysis, elastic-plastic, B21 elements.

udfpbxsf.f

User subroutine USDFLD used in udfpbxsf.inp .

udfpcxsf.inp

Static analysis followed by frequency analysis, elastic-plastic, CPE4 elements.

udfpcxsf.f

User subroutine USDFLD used in udfpcxsf.inp.

udfpsxsf.inp

Static analysis followed by frequency analysis, elastic-plastic, S4/S4R elements.

udfpsxsf.f

User subroutine USDFLD used in udfpsxsf.inp.

Figures

Figure 1. Hypoelastic model comparison.