Objective: Generate CAD Entities that represent the stiffener of a HyperX stiffened panel or beam for the purpose of exporting optimized geometry to CAD software.
This utility can create lofted Surface or Solid entity for the stiffener of optimized Zones. The utility can be used with either the smeared or technique 2 discrete modeling techniques for stiffened panels or beams. See About Discrete Modeling Techniques. The latest Sizing results from each Zone or Panel Segment are used to generate the stiffener geometry.
For discretely stiffened panels, the 1D elements that represent the stiffener are used to define the location of the generated CAD geometry. For smeared stiffened panels and beams, CAD Curves are used define the position of the stiffeners. The stiffener is offset from the mesh by the thickness of the skin for both modeling approaches.
The output is intended to be a reference for CAD designers and therefore does not include features such as fillets or smooth transitions in stiffener height. The output entities are broken up by Zone boundaries, with a constant stiffener cross section within the boundary.
Important
When using this utility with smeared stiffened panels on thin structures (such as a wing), or structures that have a "U" shape, it is recommended to generate the stiffener geometry with multiple runs of the utility. This can avoid issues with multiple possible projections of the guide curve onto different Zones. In the case of a wing, run the top and bottom skins separately.
-
Zones with a uniaxial stiffener concept assigned (See here to generate grid concepts).
-
Sizing results using the Detailed Sizing mode.
-
For smeared stiffened panels and beams, CAD Curves are needed to dictate stiffener location.
Select either Zones with a smeared stiffener concept or panel segments using technique 2 stiffeners. Both types cannot be selected simultaneously.
If smeared stiffeners are used, select CAD Curves that define stiffener location. The Curves should be close to the Zones so that they are projected correctly.
Three settings control where stiffeners are generated relative to the Structure mesh:
-
Midsurface - Generates a Surface at the middle of the stiffener profile, instead of a 3D volume representing the stiffener. The midsurface is intended to be exported and used for meshing.
-
Opposite Normal - Determines which side of the mesh the stiffener is generated. By default, the stiffeners are generated opposite of the element normals, which is the standard HyperX analysis approach. If the option is inactive, the stiffeners will be generated on the same side as the element normal vectors.
The images above show stiffeners generated for the same Zone and Guide Curve. The stiffener on the right was generated with "Opposite Normal" selected.
-
Skin Offset - Determines the distance between the mesh and where the stiffener is generated. If active, the stiffener is shifted away from the mesh by a distance equal to the skin thickness result on that Zone. If inactive, the foot of the generated stiffener will be coincident with the mesh.
The images above show stiffeners generated for the same Zone and Guide Curve. The stiffener on the bottom was generated with "Skin Offset" selected.
Two types of 3D profiles are available for the lofted stiffeners.
-
Surface - Generated by lofting the stiffener profile along the axis of the stiffener. Results in a stiffener profile with openings at either end.
-
Solid Geometry - Similar to the above, except the output stiffener is a solid entity with closed ends.
Two options are available for 2D geometry.
-
Multiple along Stiffeners - Produces a 2D profile of the stiffener at both ends of the stiffener section as well as at the center of the stiffener. Two profiles are generated at the center if there are an even number of elements along the guide curve in that Zone.
-
Single at Zone Centroid - Produces a single 2D profile of the stiffener at the geometric centroid of the Zone.
Clicking the Apply button will generation CAD geometry according to the selected settings. The generated geometry will be organized into folders in the CAD Tree according to the parent Zone (from which the stiffener dimensions were acquired). The geometry is also automatically associated with the Zone and will be selected whenever the Zone itself is selected.
-
Export CAD entities