VII.4.4.3 composite post-processing

Function “getCompositeRF” of “ExtractionCriteria” VBA module calculates reserve factors using the classical laminate analysis. More precisely, the Shell Forces and Moments are recovered on shell elements with laminated properties (PCOMP or PCOMPG properties), and the layered reserve factors are calculated using “calcFiniteElementResponse” method of the generic Database class. Note however that one limitation of this post-processing function is that no thermo-elastic or hygro-elastic contribution is taken into account in the post-processing. Reserve factors are generally calculated at mid thickness of each layer. One exception is the inter-laminar shear stress reserve factor which is calculated at bottom sub-layer of the selected plies.

Function “getCompositeRF” has the following arguments:

1.

The name of the load case for which the calculation is done.

2.

The location(s) in elements of the points at which reserve factors will be calculated. (For example “ElemCenters” or “ElemCorners”.)

3.

The name of a Group on which the reserve factors are calculated.

4.

The name of the failure criterion for which reserve factors are calculated. (The list of available criteria is summarized in Table II.1.2.)

5.

A selection of cells containing the list of layers on which the composite criterion is to be estimated.

6.

The factor of safety.

7.

Two optional String arguments corresponding to the name of the GMSH file in which the envelope of inverse reserve factors shall be saved, and the name of the Result by which the Result is referred to in GMSH.

The function returns an Array of one line and five columns containing:

1.

The element ID for minimum reserve factor.

2.

The node ID for minimum reserve factor.

3.

The layer ID for minimum reserve factor.

4.

The sub-layer ID for minimum reserve factor.

5.

The minimum reserve factor.

The use of “getCompositeRF” function is illustrated in “post_composite” worksheet.

“getCompositeRF2” function defined in “UserCriteria” Module is a variant of “getCompositeRF” with two additional arguments:

• “bCurvature” is a boolean that specifies that one loads the laminates with “Curvature Tensor” instead of “Shell Moments Tensor” to calculate laminate load response. item “tempFieldId” corresponds to an integer that allows to retrieve a temperature field from “sqliteResults.db3” database to load the laminate. This contribution is taken into account if the database is located in excel working directory, and if the specified temperature field is found in the database. In the example, the “TempLoad” parameter is used to associate the temperature fields to post-processing load case.

Note that one explains in section IV.2.8.5 how the SQLite database containing the temperature Results can be produced.

“getCompositeRF3” function defined in “UserCriteria” Module is a variant of “getCompositeRF” that calculates laminate failure criteria directly from the stresses extracted from finite element model results. This function has been used to test the different variants of the functions calculating laminate criteria. The arguments of this function are the same as those of “getCompositeRF” function.