Seminar "Sesam Present & Future" in Rio on Sept 2nd 2011, presented by Ole Jan Nekstad

1. 1
SesamTM
40 years of success
GeniE – Shell modelling, status and directions
Ole Jan Nekstad, Sesam Product Manager, DNV Software
1 September 2011

2. Shell modelling - status
SesamTM
1 September 2011
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3. Shell modelling functionality
 4 main options – they are all based on curves Curve net interpolation
Skin/loft
Cover
Extrude
SesamTM
1 September 2011
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4. Skin / loft curves
 Usually works fine with all types of curves
- If not, a trick may be to rebuild the curves with the same number of points
 May get gaps between adjacent shells in the cross direction of the skinning
direction
Gap, elements don’t
share the same nodes
 Workaround is to use a model curve from adjacent shell in further modelling
SesamTM
1 September 2011
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5. Use existing shell edge (model curve)
 Use model curve of shell edge to ensure topological congruency
 May skin/loft, cover or net interpolate adjacent shell, as long as the model curve is
used
- Trimming of curves required?
SesamTM
1 September 2011
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6. Curve net interpolation
 Use net of interior and/or boundary curves
- Does not require trimming of curves OK
- Requires common intersection points
SesamTM
1 September 2011
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7. Internal edges
 Composite curves may give internal edges
- Same issue with skin/loft
- Use global meshing rule Remove internal edges
SesamTM
1 September 2011
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8. Conclusion
Preferred approach:
Use polycurves and curve net interpolation
Need common intersection points
SesamTM
1 September 2011
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9. New features for shell modelling
in GeniE v5.3-10 released April
2011
SesamTM
1 September 2011
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10. Why enhancements to existing modelling capabilities
Models like this can be created today.
We have identified potential user efficiency gains
within local modelling details and flat surface modelling
SesamTM
1 September 2011
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11. Easier modelling of planar surfaces
 Create closed surfaces by single click using flat region feature
- Intuitive and simple to use.
- Bounding by existing plates, beams and guide curves
- No need to split lines
Insert  Plate  Flat Region Plates, beams and curves Click inside area.
to position cut-plane in cut-plane Uses visible model
SesamTM
1 September 2011
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12. Additional options in vector selection dialog
 Vector from other object
- local beam system
- plate normal
- 3-point plane normal, etc
SesamTM
1 September 2011
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13. Additional options in snap plane and divide dialogs
 Plane defined by three points
SesamTM
1 September 2011
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14. More features for making geometry
 Scaling and offsetting of curves and surfaces makes it easier to make regular as
well as complex geometrical shapes
- Scaling around a point is often used to create similar shapes for the purpose of making
structure and controlling finite element mesh, Edit  Copy
- Offsetting will create similar shape (line or surface) in a given distance
SesamTM
1 September 2011
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15. Meshing improvements
 Separated handling of mesh and loads use less peak memory
 Conditional Regenerate Mesh
- For large models, significant performance improvements are achieved when updating
analysis models
- Does not have to regenerate mesh if only properties
or loads are changed. FEM file is updated instead.
- Topology and mesh rule changes force new mesh
SesamTM
1 September 2011
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16. Ongoing modelling activities
SesamTM
1 September 2011
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17. Ongoing activities
 64-bit version of GeniE – tentatively release date September 2011
- Performance improvements, “unlimited” memory available – important for large models
(e.g. global FPSO model)
- ISO Joint Check “critical” joints, the option to compute “Ub from run” is now available
- Sacs Import : Result combinations read into GeniE
- Frame code checks : Results stored on HDF5 files, reducing chance of running out of
virtual memory
SesamTM
1 September 2011
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18. Ongoing activities – scheduled for release Q1/2012
 Additional ways for modelling of guiding points and curves
 Common representation of all curves using NURBS
Pictures from prototype implementation
SesamTM
1 September 2011
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19. Ongoing activities – some examples
 E.g. Different type of line representations
Guide Spline Poly Curve Bezier Curve S/P Spline Curve
Classic cubic G1 curve, consisting
Polynomial line. Shape-preserving
spline interpolation of linear and cubic
Shape decided by interpolating spline
segments, which
control points, but no
interpolates
interpolation
the given points
SesamTM
1 September 2011
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20. Ongoing activities – some examples
 Bezier curve and control points – shape preserving curves
- Gives the user much more flexibility in creating almost any curve
Three control points Four control points – Four control points
the middle point is used twice
SesamTM
1 September 2011
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21. Ongoing activities – scheduled for release Q1/2012
 New DXF import using the
Rhinoceros plug-in
 Poly-lines supported with
new NURBS
implementations
SesamTM
1 September 2011
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22. Our biggest challenge when importing line data
 Real case example – importing data from NAPA
But often lines do not
intersect
All looks fine!
SesamTM
1 September 2011
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23. Ongoing activities – scheduled for release Q1/2012
 Mapping of one set of curves onto another
set, e.g. buttocks onto station curves/offset
table
- GeniE will propose a cleaning of non-matching
lines
- User to decide which line to “move” to achieve
matching lines
Two lines are not matching
All lines are matching
SesamTM
1 September 2011
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24. Safeguarding life, property
and the environment
www.dnv.com
SesamTM
1 September 2011
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