GCD Extraction for Composites

Geometry extraction for Composites parts recognizes some Composites-specific GCDs: Ply GCD and Core GCD. In addition, the Component GCD has several properties that are process-group-specific or have process-group-specific meanings.

Some of the Ply and Core properties are extracted from CAD file metadata (for example, the Material Name, Orientation, and Sequence for a given ply). A Composites mapping file allows aPriori to convert the metadata into GCD property values that can be used by the cost model. The default mapping file supports CAD files that contain published Fibersim or CPD ply design data. The mapping file is a fully customizable XSLT file. If you need to support additional metadata formats, contact aPriori Professional Services.

Component GCD

Important properties of the Component GCD include the following:

• Perimeter: total length of the part’s external and internal contours.

• External Perimeter: total length of the part’s external contour.

• Surface Area: surface area of the part.

Ply GCD

Important properties of the Ply GCD include the following:

• Length and Width: this is determined based on the smallest rectangle that (a) encloses the flattened ply, and (b) has a side aligned with the ply’s fiber direction. In particular, ply Length is the length of a side of this rectangle that is aligned with the ply’s fiber direction, and ply Width is the length of a side of this rectangle that is perpendicular to the play’s fiber direction.

• Surface Area: surface area of one side of the flattened ply. This does not include the area of cutouts.

• Surface Area Filled: area of the flattened ply’s convex hull. The convex hull is the region that would be enclosed by a string pulled taught around the edges of the ply; it is the smallest convex region that encloses the flattened ply.

The area of this region approximates the area of the ply prior to the removal of cutouts. It helps determine ply layup rate. See Ply Placing Operation for Hand Layup, Ply Placing Operation for Automated Tape Layup, and Ply Placing Operation for Automated Fiber Placement.

• Average Curvature: this is the ply’s average Gaussian curvature. Total average curvature is the product of this geometric property and Surface Area Filled. Used to determine Ply Deformation Level.

• Max Curvature: this is the ply’s maximum Gaussian curvature. Total maximum curvature is the product of this geometric property and Surface Area Filled. Used to determine Ply Deformation Level.

• Curvature Deviation: this is the standard deviation of the Gaussian curvature across the ply. Total curvature standard deviation is the product of this geometric property and the Surface Area Filled. Used to determine Ply Deformation Level.

• Direction: this is the 0 direction of the rosette, specified as a unit vector. It specifies how the ply is oriented with respect to the part as a whole.

• Orientation: this is the angle between the 0 direction of the rosette and the ply’s fiber direction (that is, the direction of the ply’s warp tows).

• Sequence: determines the order in which the ply is laid up. This is set to -1 if the ply’s ordering information is not available in CAD metadata.

• Material Name: specifies the material used by the ply, as extracted from the CAD model. The cost model uses this name to look up material properties in the material table for the current VPE. See Materials for Composites.

Core GCD

The cost model uses the following Core GCD properties:

• Material Name: specifies the material used by the core, as extracted from the CAD file metadata. The cost model uses this name to look up material properties in the material table for the current VPE, for example, in order to determine the cost per unit area for a given core’s material. See Materials for Composites.

• Perimeter: perimeter of the core. This is the total length of the core edges that must be aligned with a template during core placement.

• Sequence: determines the layer in which the core is placed. This is set to -1 if the core’s sequence information is not available in CAD metadata.

• Surface Area: surface area of the core, including all surfaces of the core.

• Purchase price: cost per unit area for the core.