Sesam - Efficient Engineering of Topside Structures

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Seminar "Efficient Design of Topside Structures" (Rio, May 10 2011) by Pal Dahlberg

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Sesam - Efficient Engineering of Topside Structures

  1. 1. 1SesamTM40 years of successEfficient engineering of topside structuresPål Dahlberg, Sesam Principal Sales Executive, DNV Software10 May 2011
  2. 2. Efficient engineering of topside structures  Save man-hours and increase quality by using the latest available capabilities in concept technologies for - Structure modelling - Loads & Environment modelling - Forces, stresses, deflections - Local models in global model - Beam code checking - Design iterations including redesign of members - Plate code checking - Fatigue (separate presentation) Wave or wind inducedSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 2
  3. 3. Common challenges in designSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 3
  4. 4. The importance of the Sesam design loop 40-60% of engineering time often spent in evaluation How fast can you do it over again?SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 4
  5. 5. Closing the design loop – our strength  Efficient data transfer from initial modelling through analysis, results processing and code checking - “How long time does it take from modelling to first result?”  Efficient member code check iterations - “What is the effect of modifying a section or code check parameters without re-running complete analysis?”  Efficient update of model based on code check iterations - “How long time does it take to re-generate a code check-report based on a full re-run of model and analysis”SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 5
  6. 6. How can Sesam help you – Making a model in GeniE StructureSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 6
  7. 7. Structure modelling  Easy to facilitate the range from small to large and complexSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 7
  8. 8. GeniE uniqueness – structure modelling  Always a consistent concept model – made for frequent design changes - Analysis models (FEM) derived from the concept model - Beams and plates always connected, can be disconnected by use of s.el. techniqueSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 8
  9. 9. GeniE uniqueness - combined beam/shell models  Faster modelling  Faster and easier re-analysis and - Stiffeners selected from libraries optimization - No need for calculation and evaluation of - Easy change of beam profiles from libraries effective flange - Plate thickness changed without changing - No lumping of loads properties for all stiffeners - No doubts – model structure as is - Easy to change geometry, stiffener arrangement - Always a consistent topology and other properties - Easy to add new stiffeners or other details  More accurate results (brackets, holes etc.) - No simplified assumptions on effective flange and lumping of loads - Better visual verification of model and resultsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 9
  10. 10. GeniE uniqueness – structure modelling  Parametric modelling – define variables in script files 4.23E07 5.E07SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 10
  11. 11. GeniE uniqueness – structure modelling  Same system – offshore and maritime - Fixed structures, semi’s, FPSO’s, Spar, TLP - Tankers, containership, bulk, +++SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 11
  12. 12. SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 12
  13. 13. GeniE uniqueness – structure modelling  Combine detailed models in a global model Beam Plates FE beam FE shellSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 13
  14. 14. GeniE uniqueness – structure modelling  Local models - Easy to go from global to many local models – all are based on the same concept modelSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 14
  15. 15. How can Sesam help you – Making a model in GeniE LoadsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 15
  16. 16. Load application  Easy to include load sources from structural mass (gravity and accelerations), equipments, manually defined loads, rule based loads (compartment loads) and temperature loadsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 16
  17. 17. GeniE uniqueness – load application  Easy to define compartment loads - Content and filling degree is enoughSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 18
  18. 18. GeniE uniqueness – load application  Acceleration loads – multiple choices - Constant and varying acceleration – different accelerations on various parts of structure Lower level loads from mass Upper level loads from Rotational acceleration x acceleration (x & z-dir) mass x acceleration (z-dir) Harmonic induced wave motionSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 19
  19. 19. Topsides/modules on jackets or floaters  Topside on Jackets  Topside on Floaters - All is done inside GeniE - Opt. 1 - Integrated: Results from HydroD - Focus of this presentation (hydrodynamic frequency or time domain analysis) imported into GeniE - Opt. 2 - No load transfer: Accelerations and deflections are computed in HydroD and used as basis for load-cases in GeniESesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 20
  20. 20. Floaters – frequency domain  Waves give deformations and stresses in topsides and modulesSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 21
  21. 21. Floaters – frequency domain  Waves give deformations and stresses in topsides and modules - These must be converted to deterministic before import to GeniE - Our utility tool Prepost is used for this purposeSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 22
  22. 22. Floaters – optionally no automatic load transfer  Deformations and accelerations used to define load cases in GeniE - Accelerations constant or centripetal (from HydroD) - Deformations from global structural analysis (used as prescribed displacements in GeniE)  Sp1: 2mm  Sp2: 3mm  Sp3: 5mm Centripetal Acceleration  Sp4: 2mmSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 24
  23. 23. Reporting  All reports can be reproduced and automatically recreated - The report generation is scripted - Text, html, Excel(xml), Word(xml)  The user decides the content - Structure - Properties - Masses - Loads - Analysis (FEM) results - Frame code check - Plate code checkSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 25
  24. 24. Demo-time Make a local shell joint in a topside modelSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 26
  25. 25. Demo case – The model  A traditional topside model build from beamsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 27
  26. 26. Demo case – The loads  A combination of equipment and acceleration loadsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 28
  27. 27. Demo case – The results  Viewing results in plug-in component for online presentation purposesSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 29
  28. 28. Demo case – Deformations at selected joint  The selected joint will be converted to a shell model - Beam model: Max deformation is 3.6 mmSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 30
  29. 29. Demo case – Deformations at selected joint  The joint is now a shell model part of the global model - Combined beam and shell model: Max deformation is 3.6 mmSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 31
  30. 30. Demo case – Deformations at selected joint  Consistency between beam and shell elementsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 32
  31. 31. Demo case – The results  Viewing results in plug-in component for online presentation purposesSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 33
  32. 32. Demo case – speed!  Question becomes – how long time does it take to convert the beam joint to a shell model and re-run analysis? - 1 day - 1 hour - 30 min? - 5 min? - 4 min?  You can start your stop watches now - …..and not using a predefined special purpose build script for this case….SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 34
  33. 33. Demo case – add details  Add bracketsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 35
  34. 34. How can Sesam help you – First assessment in GeniESesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 36
  35. 35. Efficient engineering – typical steps  First assessment - Forces, stresses and deflections  Code checking - Check against prescriptive standards  Member re-design - Evaluate the effect of modifying section properties or code check parameters - Often many attempts – depends on the engineer’s experience  Design iteration - A complete re-run of all to document the re- designSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 37
  36. 36. Beam forces and stresses  Forces and stresses in 2D view as well as tabularSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 38
  37. 37. Beam forces and stresses  Force envelope  Stress envelopeSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 39
  38. 38. Beam deflections – 3D view  Standard 3D deformation view  Using the option to compute beam deflections without increasing number for finite elements (absolute deflections)SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 40
  39. 39. Topside – 3D beam deflection view  The effect of adding cubic deformations With cubic deflection Linear deflection ≈ deformation viewSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 41
  40. 40. Beam deflections – 2D view  Dy, Dz and Defl = sqrt(Dy^2 + Dz^2)  Per load-case(s)  Envelopes  Worst condition  Relative deflectionsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 42
  41. 41. Beam deflections – tabular report  3 results are reported - Beam length (flexible length) - Deflection (deflections & rotations) - relative - DELTA = Flexible beam length/Deflection - 5-11 points may be reported per beam - All positions or worst positions - Per load-case or envelopes (scan)SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 43
  42. 42. Topside – check deflection ratio against AISC levels  AISC: Allowable deflection ratio 180, 240, 360 and scanning all load casesSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 44
  43. 43. Excellent design – a real case scenario  Part of a super-element analysisSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 45
  44. 44. Topside – all in one view  You decide what you want to seeSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 46
  45. 45. How can Sesam help you – Beam code checking in GeniESesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 47
  46. 46. Code checking in GeniE - members  Supporting - API WSD 2002/AISC ASD 2005 - API WSD 2005/AISC ASD 2005 - API LRFD 2003/AISC LRFD 2005 - NORSOK 2004/Eurocode 3 1993 - ISO 19902 2007/Eurocode 3 1993 - DS 412/449SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 48
  47. 47. Easy to create capacity members  Members may be defined using complete structure or sub-sets - Global default buckling lengths decided by the engineer Buckling length? Buckling length? Buckling length?SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 49
  48. 48. Document code check results  Graphically – complete modelSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 50
  49. 49. Document code check results  Graphically – parts of structure onlySesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 51
  50. 50. Report code check results Loadcases Utilisation factor  Print out using filters - All - All - Worst - Above - User defined - Below Positions Members - All - All - Worst - Current selectionSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 52
  51. 51. Report code check results  Example on layoutSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 53
  52. 52. Efficient redesign of members  Redesign (“design iterations”) - Step1: Preliminary results when modifying section, material, stiffener spacing or buckling length parameters - Note: The loads and stiffness are not updated - Step2: Commit changes to model - Step3: Re-run analysis and code check - Reports may be automatically re-createdSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 54
  53. 53. Redesign – single members  Select a capacity member for redesign  Modify parameters - Preliminary results automatically computedSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 55
  54. 54. Redesign – single members  Look at all details (Full Table) - Shown with colour codingSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 56
  55. 55. Redesign – re-run all  The “Run All” command will - Update structure from members - Run analysis - Generate code check loads (positions) - Execute code checkSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 57
  56. 56. Redesign – multiple members  Select capacity members for redesign  Modify parameters - Preliminary results automatically computedSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 58
  57. 57. Redesign – segmented beams  Single or multipleSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 59
  58. 58. Redesign – segmented beams  Before and afterSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 60
  59. 59. How can Sesam help you – Plate code checking in GeniESesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 61
  60. 60. Code checking of stiffened panels  Create panels - Panels are independent of analysis and finite element mesh  Three different options to define panels - Min Box finds the smallest idealised rectangular panel possible enclosing the possibly non- rectangular structural region - Max Area Moment is an alternative algorithm finding the major axis based on calculation of area moment of inertia of the surface. This algorithm will also work for irregular panel Min Box shapes - CSR Tank Default is the algorithm usually used when doing a CSR Tank (PULS) code check Max Area MomentSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 62
  61. 61. Code checking of stiffened panels – ships and offshore  Code checking according to PULS (DNV RP-C201.2) - Linear and non-linearSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 63
  62. 62. Code checking of stiffened panels - offshore  Yield check of plates – based on membrane stress - Includes a safety factor SSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 64
  63. 63. Code checking of stiffened panelsSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 65
  64. 64. Code checking of stiffened panels  Demo case - PULS non-linear on stiffened panel - Simplified yield check of plates in stiffened panel (membrane stresses)SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 66
  65. 65. How can Sesam help you – Multiple analysis in GeniESesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 67
  66. 66. Multiple analysis The “master”  Multiple analysis in same project model - E.g. Lifting, transport, in-place - Varying parameters - Structure - Boundary conditions - Load casesLifting Condition Transport Condition In_place ConditionSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 68
  67. 67. Multiple analysis – graphic results  Different results at your finger-tips - Bending moments shown Lifting Condition Transport Condition In_place ConditionSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 69
  68. 68. Multiple analysis – code check results  Different results at your finger-tips - API WSD and default settings used in example below Lifting Condition Transport Condition In_place Condition Max Uf = 2.51 Max Uf = 1.85 Max Uf = 4.58SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 70
  69. 69. Multiple analysis  Frigg TCP2 MSF removal Transportation MSF: Main Support Frame Lifting ConditionSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 71
  70. 70. How can Sesam help you – What is unique about us?SesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 72
  71. 71. Our value proposition and uniqueness  An integrated and scalable life cycle solution for optimizing fixed and floating structure design, modification and operation  Accumulates 50 years of software experience from the maritime and offshore industry  Commercial benefits - One vendor delivering a complete software suite for engineering design of ship and offshore structures - Proven track record on work done on structures - Global presence with local sales, support and training - Scales with your business - Flexible licensing model - SW revenues used for further development – there are no share dividends to stock ownersSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 73
  72. 72. Our value proposition and uniqueness  Closing the design loop by modern concept modelling and work process tools - Quick modelling - Local model in global model - Scripting/parametric models - Changes during design - One model – many analyses - Interaction with hydro - Advanced hydrodynamics - Beam/plate code checking - Beam/plate fatigue - Non-linear pushover - ReportingSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 74
  73. 73. What’s needed to do topsides?  Full blown version of GeniE - Including waves, current, wind and soil - For floating structures – HydroD is needed  GeniE.lite - Limited by model size - 500 beams or 10.000 finite elements - No plate code checking, waves, current, wind and soilSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 75
  74. 74. “Keppel is very pleased to participate and being consulted in the development of the redesign feature to be launched in GeniE.” Gao Ming, Keppel Offshore and MarineSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 76
  75. 75. Safeguarding life, property and the environment www.dnv.comSesamTM25 March 2011© Det Norske Veritas AS. All rights reserved. 77

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