Post on 21-Dec-2015
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American Bureau of ShippingIntroduction To ABS Rules
American Bureau of ShippingIntroduction To ABS Rules
PresentationPresentation t to the Naval Academyo the Naval Academy
6 April 20056 April 2005
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What is Classification?What is Classification?
Classification is a process which certifies adherence to a recognized set of technical standards, representing that a ship or other type of marine structure is structurally sound and mechanically fit for its intended purpose.
Classification is third party certificationin the marine industry
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The Classification ProcessThe Classification Process
Develop Technical Standards (Rules)Developed through industry-based
technical committee structureEmbraces recognized external standardsUpdated annuallyCustomized when necessary
(new technology/new application)
Implement Technical Standards Design Plan review and engineering analysisSurvey during constructionPeriodic survey throughout vessel life
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The Classification ProcessThe Classification Process
Rules and GuidesRules and Guides
RedundantPropulsion
Guide MODU Rules
High Speed Craft Guide
SWATH Guide
Steel Vessel Rules
Rules are the foundation of the processOver 60 sets of Rules and GuidesDeveloped with industry
Industry Committee BasedPeer review from all relevant partiesContinual feedback and updateCalibrated to proven experience
Naval Vessel Rules
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world leader in ship safety and environmental protection since 1862
1500 people 225 offices 81 countries ISO 9000 certified
60+ Rules and Guides
10,000 ships in class (250+ Government)totaling over 100 million gross tons
20,000 manhours engineering review per month708 new construction ships under survey (15 million gross tons)
AIndustry and Government Involved in Management and Operations
ABS - a SnapshotABS - a Snapshot
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Engineering GroupEngineering Group
OED - Offshore Engineering DepartmentOED - Offshore Engineering Department AA - Advanced Analysis DepartmentAA - Advanced Analysis Department SED - Ship Engineering DepartmentSED - Ship Engineering Department Materials & Welding DepartmentMaterials & Welding Department Naval Engineering DepartmentNaval Engineering Department
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Ship Engineering DepartmentShip Engineering Department
Tanker / Bulk Carrier / Ship Safety GroupTanker / Bulk Carrier / Ship Safety Group General Cargo Ship GroupGeneral Cargo Ship Group Tonnage Tonnage Load Line Stability GroupLoad Line Stability Group
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ABS RulesABS Rules Steel Vessel RulesSteel Vessel Rules
Steel BargesSteel Barges - Ocean Service Barges of any Length - Ocean Service Barges of any Length
Steel Vessels Under 90 m Steel Vessels Under 90 m - Crewboats, Tugs- Crewboats, Tugs
High Speed Naval Craft- Patrol Boats HSVsHigh Speed Naval Craft- Patrol Boats HSVs
Steel Vessels for Service on Rivers, ICWSteel Vessels for Service on Rivers, ICW - River Barges, Towboats - River Barges, Towboats
Bulk Carriers for Service on the Great LakesBulk Carriers for Service on the Great Lakes - Freshwater Operations - Freshwater Operations
Reinforced Plastic VesselsReinforced Plastic Vessels - F. R. P. Vessels - F. R. P. Vessels
Aluminum VesselsAluminum Vessels - Aluminum Commercial Vessels 100’ - 500’ - Aluminum Commercial Vessels 100’ - 500’
Naval Vessel RulesNaval Vessel Rules
MODU MODU - Mobile Offshore Drilling Units- Mobile Offshore Drilling Units
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ABS GuidesABS Guides Motor Pleasure YachtsMotor Pleasure Yachts - Steel, Aluminum, or FRP - Steel, Aluminum, or FRP
High Speed CraftHigh Speed Craft, - Commercial/Government Service Planing vessels, - Commercial/Government Service Planing vessels
Fishing VesselsFishing Vessels - Steel Fishing Vessels Under 90 m (200’) - Steel Fishing Vessels Under 90 m (200’)
Offshore Racing YachtsOffshore Racing Yachts - Steel, Aluminum, or FRP Sailing Vessels - Steel, Aluminum, or FRP Sailing Vessels
Fire Fighting VesselsFire Fighting Vessels - Steel Fireboats - Steel Fireboats
Crew Accommodations GuideCrew Accommodations Guide
Oil Recovery VesselsOil Recovery Vessels - Oil Spill Cleanup Vessels - Oil Spill Cleanup Vessels
Floating Production Storage and Offloading VesselsFloating Production Storage and Offloading Vessels - (FPSO) - (FPSO)
Small Waterplane Area Twin Hulled VesselsSmall Waterplane Area Twin Hulled Vessels - (SWATH) - (SWATH)
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Ship Acquisition ProcessShip Acquisition Process
Build-to-Print
C-Spec
B-Spec
A-Spec
ORD
MNS
Technical Validation CLASSIFICATION
Requirement Derivation RULES
Owner
Contractor
Optional Step
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Function - Fitness - Safety Function - Fitness - Safety
Classification RulesClassification Rulesstructural and mechanical fitness
physical attributes of ship
Statutory ComplianceStatutory Compliancesafety of life issues
environmental protection
Owner’s RequirementsOwner’s Requirementsnot addressed elsewhere
mission relatedowner unique
Baseline Technical StandardsBaseline Technical Standards
Detailed Component and
Performance Standards
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Hull Classification Hull Classification ConsiderationsConsiderations
Intact and Damaged StabilityIntact and Damaged Stability– Specialized Vessel CriteriaSpecialized Vessel Criteria– Freeboard AssignmentFreeboard Assignment
Strength of Hull StructureStrength of Hull Structure– Longitudinal Strength RequirementsLongitudinal Strength Requirements– Local Strength RequirementsLocal Strength Requirements
Condition AssessmentCondition Assessment– Surveys During ConstructionSurveys During Construction– Surveys In-ServiceSurveys In-Service
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Structural AnalysisStructural Analysis
1. Load Determination - “What are the Loads?’1. Load Determination - “What are the Loads?’
2. Response Determination - “How do these loads 2. Response Determination - “How do these loads affect the Structure?”affect the Structure?”
3. Strength Evaluation - “Are the structural 3. Strength Evaluation - “Are the structural arrangements and materials adequate arrangements and materials adequate
for the for the determined response?”determined response?”
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Ship StructureShip StructureShip StructureShip Structure Longitudinal Strength (Continuous Members)Longitudinal Strength (Continuous Members) Local Plating/Stiffener RequirementsLocal Plating/Stiffener Requirements Main Supporting MembersMain Supporting Members
– Longitudinal/Transverse BulkheadsLongitudinal/Transverse Bulkheads
– Web FramesWeb Frames AppendagesAppendages
– Rudder/SkegRudder/Skeg
– Bilge KeelBilge Keel MaterialsMaterials
– Grade ( Strength & Toughness )Grade ( Strength & Toughness )
– Castings / ForgingsCastings / Forgings
– WeldingWelding
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Longitudinal StrengthLongitudinal StrengthUnified IACS RequirementUnified IACS Requirement
Still Water Bending MomentStill Water Bending Moment Wave Bending MomentWave Bending Moment
– Hogging ConditionHogging Condition– Sagging ConditionSagging Condition
Total Bending MomentTotal Bending Moment
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Hold Frames
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Hold Frames
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DECK GIRDERS AND PILLARS
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Strength EvaluationsStrength Evaluations Material SelectionMaterial Selection
– Grade (Strength vs. Toughness)Grade (Strength vs. Toughness)– Castings/ForgingsCastings/Forgings– WeldingWelding– Service TemperatureService Temperature– ThicknessThickness
Failure ModesFailure Modes– YieldingYielding– Buckling Buckling – FatigueFatigue– FractureFracture
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Fatigue AssessmentFatigue Assessment
Description of the EnvironmentDescription of the Environment Calculations of Ship Motions, Sealoads, and Local Calculations of Ship Motions, Sealoads, and Local
Hydrodynamic PressuresHydrodynamic Pressures Calculations of Structural Response and Stress Calculations of Structural Response and Stress
Transfer FunctionTransfer Function Selection of Appropriate S-N Curves and Stress Selection of Appropriate S-N Curves and Stress
Concentration FactorsConcentration Factors Estimation of Fatigue Life and Comparison with Estimation of Fatigue Life and Comparison with
Acceptance CriteriaAcceptance Criteria
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Semi–EmpiricalSemi–Empirical Approach to Hull ClassificationApproach to Hull Classification
Main Supporting Members
P
Local Strength
Longitudinal Strength
Material Requirements
Buckling (Both)
Fatigue (Implicit)
Fracture (Implicit)
Yielding (Explicit)
Strength vs.Toughness
AnalysisResponse Determination
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Semi-Empirical RulesDerived from First Principles
Stiffeners (beams)Stiffeners (beams) Assume Fixed End Beams where M Assume Fixed End Beams where M
= wl= wl2 2 / 12/ 12 w = s h & SM= M / Fw = s h & SM= M / Fbb
Allowable Stress FAllowable Stress Fbb = 15.68 KSI or = 15.68 KSI or 20.16KSI for Ordinary Steel F20.16KSI for Ordinary Steel Fy y =34KSI=34KSI
ABS RuleABS Rule SM= ,0041 c h s lSM= ,0041 c h s l22
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Safehull Project ObjectiveSafehull Project Objective“ A Completely Restated Set of Hull Design and “ A Completely Restated Set of Hull Design and
Evaluation Criteria”Evaluation Criteria”
Establish Loads and Combinations Acting on the Establish Loads and Combinations Acting on the Global and Local StructureGlobal and Local Structure
Specify the Extent and Types of Analyses Specify the Extent and Types of Analyses Required to Determine LoadsRequired to Determine Loads
Establish the Required Strength of the Structure to Establish the Required Strength of the Structure to Resist Load EffectsResist Load Effects
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Traditional ApproachTraditional Approach
Nominal Loading - PrescribedNominal Loading - Prescribed
Simple Design Equations in RulesSimple Design Equations in Rules
Calibrated by Satisfactory Service Calibrated by Satisfactory Service ExperienceExperience
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Modern ApproachModern Approach
Expected Loading - CalculatedExpected Loading - Calculated
Analysis Methods to Establish Load EffectsAnalysis Methods to Establish Load Effects
Strength Performance Criteria Under Strength Performance Criteria Under Demands of LoadsDemands of Loads
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Net Ship ApproachNet Ship Approach Design Strength is Evaluated with Expected Design Strength is Evaluated with Expected
Corrosion Values RemovedCorrosion Values Removed Nominal Strength can be Preserved for the Nominal Strength can be Preserved for the
Entire Life of the VesselEntire Life of the Vessel Appropriate Corrosion Margins can be added Appropriate Corrosion Margins can be added
to Accommodate Longer Design Livesto Accommodate Longer Design Lives Allows Explicit Means to Assess Sensitivity Allows Explicit Means to Assess Sensitivity
of Structural Strength to Corrosionof Structural Strength to Corrosion
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Net Ship ConceptNet Ship Concept
CorrosionCorrosion
FatigueFatigue
Corrosion/Fatigue InteractionCorrosion/Fatigue Interaction
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Net Ship Concept
Uncorroded Stiffener and Plating
Corroded Stiffener and Plating
Corrosion Margins
Location/Structural Element Recommended Corrosion Margin for Class (mm)*
Deck Plating
Side Shell Plating
Bottom Plating
Innerbottom Plating
Longitudinal Bulkhead Plating
Transverse Bulkhead Plating
Transverse & Longitudinal Deck Supporting Members
Double Bottom Tank Internals (Stiffeners, Floors and Girders)
Vertical Stiffeners and Supporting Members Elsewhere
Non-vertical Longitudinals/Stiffeners and Supporting Members Elsewhere
Cargo Tank Ballast Tank Effectively Coated
1.0
N.A
N.A
1.5
1.0
1.0
1.5
N.A
1.0
1.5
2.0
1.5
1.0
1.5
1.5
1.5
2.0
2.0
1.0
2.0
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Load ComponentsLoad ComponentsDetermined Through Parametric Seakeeping Determined Through Parametric Seakeeping
AnalysisAnalysis Hull Girder LoadsHull Girder Loads
– Still Water and Wave Induced Bending Moment and Still Water and Wave Induced Bending Moment and Shear ForceShear Force
– Vertical, Horizontal and TorsionalVertical, Horizontal and Torsional Internal Tank PressureInternal Tank Pressure
– Added Pressure Head due to Roll and PitchAdded Pressure Head due to Roll and Pitch– Internal Forces due to AccelerationsInternal Forces due to Accelerations– SloshingSloshing
External PressureExternal Pressure– Hydrostatic Pressure DistributionHydrostatic Pressure Distribution– Wave Induced Dynamic Pressure DistributionWave Induced Dynamic Pressure Distribution
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Load DeterminationLoad Determination
North Atlantic RouteNorth Atlantic Route Strip Theory for ResponseStrip Theory for Response Probabilistic ApproachProbabilistic Approach Long Term Values Incorporating:Long Term Values Incorporating:
– Wave SpectraWave Spectra– Ship HeadingsShip Headings– Service SpeedService Speed
Load Cases for Tanker Safehull
Loading Pattern of Conventional Bulk Carrier
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Summary of Criteria FeaturesSummary of Criteria Features
FormatFormat LoadsLoads ““Net-Ship” ConceptNet-Ship” Concept Strength CriteriaStrength Criteria Fatigue CriteriaFatigue Criteria Analysis to Obtain Load EffectsAnalysis to Obtain Load Effects
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Finite Element AnalysisFinite Element Analysis(Phase B)(Phase B)
3-Dimensional - Determine Global Loads 3-Dimensional - Determine Global Loads and Boundary Conditionsand Boundary Conditions
2-Dimensional - Determine Local Stress 2-Dimensional - Determine Local Stress and Deflectionsand Deflections– Yielding Yielding – Buckling Buckling – FatigueFatigue
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Naval Vessel Rules
Derived from Gen Specs and Design Data Derived from Gen Specs and Design Data SheetsSheets
Requires Analysis of Longitudinal Strength Requires Analysis of Longitudinal Strength using DDS 100 and SPECTRA Programusing DDS 100 and SPECTRA Program
Requires a FEM AnalysisRequires a FEM Analysis Uses Prescribed Loads from Traditional Uses Prescribed Loads from Traditional
Navy Criteria and Specific Design Loads Navy Criteria and Specific Design Loads Concern over Shock Load & Ship WeightConcern over Shock Load & Ship Weight
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High Speed Naval Craft
Based on Design Criteria from NSWC- CD Based on Design Criteria from NSWC- CD Combat Craft Department and NAVSEACombat Craft Department and NAVSEA
Determines Loads from Vessel Response to Determines Loads from Vessel Response to Sea State, Speed and HeadingSea State, Speed and Heading
Calculate local Slam pressures and Slam Calculate local Slam pressures and Slam MomentsMoments
Combines Slam Moment with Hull Girder Combines Slam Moment with Hull Girder Bending MomentsBending Moments