workshop 6 mid-surface extraction wing · pdf filegeneral outline of workshop steps...
TRANSCRIPT
WS6-1PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
WORKSHOP 6
MID-SURFACE EXTRACTIONWING SECTION
3D Parasolid Solids 2D Surfaces
WS6-2PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
WS6-3PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
Problem Description The design department has produced a solid model of an
aircraft wing section.
The task is to extract mid-surfaces from the solid model,preparing for shell meshing.
MID-SURFACEWING SECTION
WS6-4PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
The solid model consists of five individual solids asshown in the exploded view.
MID-SURFACEWING SECTION
WS6-5PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
The model of the wing section is shown without theupper wing skin.
Rib (3)
Rib stiffener (9)
Lower wing skin
Rib cap (6)
MID-SURFACEWING SECTION
WS6-6PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
Idealization Replace the solid geometry with surface geometry. Mesh the surfaces
to create plate elements. Mesh the edges of surfaces to create barelements.
Wing skins and ribsare modeled usingplate elements
Rib stiffeners andrib caps aremodeled usingbar elements
MID-SURFACEWING SECTION
WS6-7PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps Import the Parasolid model file wing_section.xmt_txt
MID-SURFACEWING SECTION
WS6-8PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
Rib Solids, Solid 1:3
Skin Solids, Solid 4:5
General outline of workshop steps (continued) Five parasolid solids
MID-SURFACEWING SECTION
WS6-9PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
Rib321
Solid 3.7Solid 2.7Solid 1.7Offset SolidFace List
Solid 3.5Solid 2.5Solid 1.5Solid FaceList
General outline of workshop steps (continued) Create rib surfaces
They will be the length(X-direction) of the ribs
MID-SURFACEWING SECTION
WS6-10PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Create rib stiffener surfaces
They will be the width (Z-direction) of the ribs
Solid3.41
Solid3.37
Solid3.33
Solid2.41
Solid2.37
Solid2.33
Solid1.41
Solid1.37
Solid1.33
OffsetSolidFace
Solid3.40
Solid3.36
Solid3.32
Solid2.40
Solid2.36
Solid2.32
Solid1.40
Solid1.36
Solid1.32
SolidFace
987654321
MID-SURFACEWING SECTION
WS6-11PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Created rib and rib stiffener surfaces
MID-SURFACEWING SECTION
WS6-12PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Use the manual or automatic mode to extract mid-surfaces from the
wing skin solids. Solid Face List: Solid 4.6 5.6 Offset Solid Face List: Solid 4.1 5.1
MID-SURFACEWING SECTION
WS6-13PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) There is a gap between the top or bottom of the rib/rib stiffener surfaces
and the wing skin surfaces. It is 0.050 inch which is half of the wing skinthickness.
Wing skin surface
Rib surface
Rib stiffenersurface
Gap
MID-SURFACEWING SECTION
WS6-14PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Only simple (green) surfaces can be extended. MSC.Patran will
automatically attempt to convert complex (magenta) surfaces intogreen surfaces before performing the surface extend operation.
In cases where the automatic conversion fails, a manual surface refitmay be required using Geometry: Edit/Surface/Refit.
MID-SURFACEWING SECTION
WS6-15PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Extend the rib stiffener surfaces to the wing skin surfaces to eliminate
those gaps. Do not break the wing skin surfaces during the extendoperation.
Extend rib stiffenersurface at both ends
MID-SURFACEWING SECTION
WS6-16PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Extend the rib surfaces to the wing skin surfaces to eliminate those
gaps. Do not break the wing skin surfaces during the extend operation.
Extend rib surface atboth top and bottom
MID-SURFACEWING SECTION
WS6-17PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Use the rib stiffener surfaces to break the rib surfaces. The rib surface
edges resulting from this operation can be meshed with bar elements torepresent the stiffeners.
Delete the rib stiffener surfaces.
MID-SURFACEWING SECTION
WS6-18PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Extend the wing skin surfaces 4.5 inches in the span direction.
Notice that MSC.Patran automatically refits the magenta surfaces to greensurfaces.
Note that the surface extension retains the contour of the surface.
MID-SURFACEWING SECTION
WS6-19PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) For a further demonstration of the Surface Extend tool, use the extend
by percentage to lengthen the cord of the wing skin by 10% inanticipation of front and rear spars.
MID-SURFACEWING SECTION
WS6-20PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
General outline of workshop steps (continued) Finally associate the upper and lower rib surface edges with the wing
skin surfaces. This will enforce congruent meshes between the ribs andwing skins.
MID-SURFACEWING SECTION
WS6-21PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation
MID-SURFACEWING SECTION
WS6-22PAT302, Workshop 6, December 2004Copyright2004 MSC.Software Corporation