*DSLOAD

Keyword type: step

This option allows for (a) the specification of section stresses on the boundary of submodels, cf. the *SUBMODEL card and (b) the application of a pressure on a facial surface.

For submodels there are two required parameters: SUBMODEL and either STEP or DATA SET. Underneath the *DSLOAD card faces are listed for which a section stress will be calculated by interpolation from the global model. To this end these faces have to be part of a *SUBMODEL card, TYPE=SURFACE. The latter card also lists the name of the global model results file.

In case the global calculation was a *STATIC calculation the STEP parameter specifies the step in the global model which will be used for the interpolation. If results for more than one increment within the step are stored, the last increment is taken.

In case the global calculation was a *FREQUENCY calculation the DATA SET parameter specifies the mode in the global model which will be used for the interpolation. It is the number preceding the string MODAL in the .frd-file and it corresponds to the dataset number if viewing the .frd-file with CalculiX GraphiX. Notice that the global frequency calculation is not allowed to contain preloading nor cyclic symmetry.

The distributed load type label convention is the same as for the *DLOAD card. Notice that

• the section stresses are applied at once at the start of the step, no matter the kind of procedure the user has selected. For instance, the loads in a *STATIC procedure are usually ramped during the step. This is not the case of the section stresses.
• the section stresses are interpolated from the stress values at the nodes of the global model. These latter stresses have been extrapolated in the global model calculation from the stresses at the integration points. Therefore, the section stresses are not particular accurate and generally the global equilibrium of the submodel will not be well fulfilled, resulting in stress concentrations near the nodes which are fixed in the submodel. Therefore, the use of section stresses is not recommended. A better procedure is the application of nodal forces (*CLOAD) at the intersection. These nodal forces may be obtained by performing a preliminary submodel calculation with displacement boundary conditions and requesting nodal force output.

For the application of a pressure on a facial surface there is one optional parameter AMPLITUDE specifying the name of the amplitude by which the pressure is to be multiplied (cf. *AMPLITUDE). The load label for pressure is P.

If more than one *DSLOAD card occurs in the input deck, or a *DLOAD and at least one *DSLOAD card, the rules explained underneath the keyword *DLOAD also apply here.

First line:

• *DSLOAD
• For submodels: enter the parameter SUBMODEL (no argument) and STEP with its argument

Following line for surface loading on submodels:

• Element number or element set label.
• Distributed load type label.

Repeat this line if needed.

Following line for pressure application on a surface:

• Surface name.
• Load label (the only available right now is P for pressure)
• Pressure.

Repeat this line if needed.

Example:

*DSLOAD,SUBMODEL,STEP=4
Se1,P3

specifies hat on face 3 of all elements belonging to set Se1 the section stress is to be determined by interpolation from step 4 in the global model.

Example files: .