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Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
Sesam for Collapse Analysis
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Sesam for Collapse Analysis

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Presentation by Pal Dahlberg on Seminar Design of Fixed Structures with DNV Software (April 2012)

Presentation by Pal Dahlberg on Seminar Design of Fixed Structures with DNV Software (April 2012)

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  • 1. 1SesamTM40 years of successSesam for collapse analysisPål Dahlberg, Sesam Principal Sales Executive17 April, 2012
  • 2. Benefits from using Sesam for jacketsNew builds covering Manage existing Collapse analysis Modification work entire life cycle re-analysis models Requalification - all phasesMTO, deflection check, Understand models over time, Extreme conditions, Design of new parts code check, fatigue produce and view results accidents, fire, explosion Re-design of existing Same model for all stages – can be shared with other units like the floating departmentSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 2
  • 3. Non-linear analysis - Re-qualification - Accidents - Collapse & large scale deformations - Fire & explosionsSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 3
  • 4. The SESAM suite of programsPackages:DeepC Coupled globalresponse of moored deep water floating systemsGeniE Design of beam and plate offshorestructuresHydroD Hydrodynamicanalysisof ship and floatingoffshore structuresSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 4
  • 5. Our tools – your solutions – your decisions xml xml Transportation, launching Transportation, lifting Deflections, Stresses, Deflections, Stresses, Code-check, Fatigue Code-check, Fatigue fem Non-linear analysis, Linear analysis (wave, pile/soil) collapse, accidents, Deflections, Stresses, re-qualifications Code-check, Fatigue, EarthquakeSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 5
  • 6. Structural analysis & design  Non-linear analysis - Accidents: Member yields and changes shape - Impact, Collision, Explosion, Dropped objects - Geometry changes significantly - Lifting operations, cable structures - Loads depend on structural response - Wave, current, wind, motions - Static analysis - Ultimate strength, Energy absorption - Dynamic simulation (of real events) - Collision, explosion, motions - Environment (wave, buoyancy, stability, wind) - Foundation - Pile, soil, spudcan (jack-up) - Temperature effects - Changed material properties, FireSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 6
  • 7. Non-linear analysis  USFOS is a specialized tool for ultimate resistance evaluation of typical offshore structures - Increased efficiency - Better numerical predictions - Lower threshold for new users to enter complex physics  The ultimate resistance of a structure is important for many reasons - New loading conditions, linear design exceeded, e.g. - Extreme waves, increased explosion pressure - Increased platform weight, extra conductors - Damaged structure (cracks etc) – necessary to repair immediately? - Energy absorption performance - Boat landing, crane operations/dropped objects, vessel impact etc.SesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 7
  • 8. Non-linear analysis in Usfos  Why non-linear - Linear codes cannot describe ductility (metal) - Linear codes cannot account for the change in geometry for increasing loads - Usfos includes “all” physical effects and predicts the “real” behaviour of a structureSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 8
  • 9. Importing models into Usfos Model consistency : GeniE Sacs Model Wave loads Soil The Sacs input file The GeniE model The Usfos modelSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 9
  • 10. Importing models to Usfos  Migration to Usfos - Detailed model not needed for Collapse analysis - This model would benefit from a “clean-up” - Deck plating  Coarse Mesh - Necessary to get rid of the small gaps - Beams  One element per physical member - Enough for detection of buckling & Plastic Hinges (end nodes + middle of beam) - Gravity + Explicit Deck Loads + Wave load (to be exported to Usfos) - More loads can easily be imported to Usfos, but they should be relevant for collapse analysis - Remove Dummy beams  Not relevant for non-linear analysis - Wave loads exported from GeniE as explicit loads - No need to define wave data and hydrodynamic coefficients in UsfosSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 11
  • 11. Importing models to Usfos  How to do it? - Start Usfos (Xact) and import the structure and wave load dataSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 12
  • 12. Collapse analysis  History Plots - Global Load vs. Displacement of Control Node (normally a node with large displacements) - Global Stiffness vs. Step NumbersSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 13
  • 13. Collapse analysis  Displacements  Plastic utilizationSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 14
  • 14. Collapse analysis  Element forcesSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 15
  • 15. Boat impact  Boat Impact - Energy specified by user to be dissipated - Local Denting of Tube - Buckling & Plastic Hinges for local Hit Member - Fracture Criteria based on strains - In this case when less 0.15 - Global Deformation of the Global ModelSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 16
  • 16. Boat impact  History Plots (Global Load = 1, means  Plastic utilisation Max Impact Energy) - Shown for control nodeSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 17
  • 17. Safeguarding life, property and the environment www.dnv.comSesamTM13 December 2011© Det Norske Veritas AS. All rights reserved. 18

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