ABAQUS Keywords Reference Manual  

*DFLUX
Specify distributed fluxes in heat transfer or mass diffusion analyses.

This option is used to apply distributed fluxes in fully coupled thermal-stress analysis. In ABAQUS/Standard it is also used for heat transfer, coupled thermal-electrical, and mass diffusion analyses.

Products: ABAQUS/Standard  ABAQUS/Explicit  

Type: History data

Level: Step  

References:

Optional parameters:

AMPLITUDE

Set this parameter equal to the name of the amplitude curve that defines the magnitude of the distributed fluxes during the step (“Amplitude curves,” Section 19.1.2 of the ABAQUS Analysis User's Manual).

If this parameter is omitted for uniform flux types in an ABAQUS/Standard analysis, the reference magnitude is applied immediately at the beginning of the step or linearly over the step, depending on the value assigned to the AMPLITUDE parameter on the *STEP option (“Procedures: overview,” Section 6.1.1 of the ABAQUS Analysis User's Manual). If this parameter is omitted in an ABAQUS/Explicit analysis, the reference magnitude is applied immediately at the beginning of the step.

For nonuniform fluxes of type BFNU and SnNU (which are available only in ABAQUS/Standard), the flux magnitude is defined in user subroutine DFLUX, and AMPLITUDE references are ignored.

OP

Set OP=MOD (default) for existing *DFLUXs to remain, with this option modifying existing fluxes or defining additional fluxes.

Set OP=NEW if all existing *DFLUXs applied to the model should be removed.

REGION TYPE

This parameter applies only to ABAQUS/Explicit analyses.

This parameter is relevant only for distributed fluxes applied to the boundary of an adaptive mesh domain. If a distributed flux is applied to a surface in the interior of an adaptive mesh domain, the nodes on the surface will move with the material in all directions (they will be nonadaptive). ABAQUS/Explicit will create a boundary region automatically on the surface subjected to the defined distributed flux.

Set REGION TYPE=LAGRANGIAN (default) to apply the distributed flux to a Lagrangian boundary region. The edge of a Lagrangian boundary region will follow the material while allowing adaptive meshing along the edge and within the interior of the region.

Set REGION TYPE=SLIDING to apply the distributed flux to a sliding boundary region. The edge of a sliding boundary region will slide over the material. Adaptive meshing will occur along the edge and in the interior of the region. Mesh constraints are typically applied on the edge of a sliding boundary region to fix it spatially.

Set REGION TYPE=EULERIAN to apply the distributed flux to an Eulerian boundary region. This option is used to create a boundary region across which material can flow. Mesh constraints must be used normal to an Eulerian boundary region to allow material to flow through the region. If no mesh constraints are applied, an Eulerian boundary region will behave in the same way as a sliding boundary region.

Data lines to define a distributed flux: 

First line:

  1. Element number or element set label.

  2. Reference flux magnitude (units of JT–1L–2 for surface fluxes and JT–1L–3 for body fluxes). It is needed for uniform fluxes only. If this value is given for nonuniform fluxes, it will be passed into user subroutine DFLUX, where the actual flux magnitude is defined.

    In heat transfer analysis the units are JT–1L–2 for surface fluxes and JT–1L–3 for body fluxes. In mass diffusion analysis the units are PLT–1 for surface fluxes and PT–1 for body fluxes.

Repeat this data line as often as necessary to define distributed fluxes for different element surfaces.