American Bureau of Shipping American Bureau of Shipping Introduction To ABS Rules Presentation to...

American Bureau of ShippingAmerican Bureau of Shipping

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


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


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


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


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


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


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


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


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)


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


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


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


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?”


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


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


Hold Frames


DECK GIRDERS AND PILLARS


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


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


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


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


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


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


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


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


Net Ship ConceptNet Ship Concept

CorrosionCorrosion

FatigueFatigue

Corrosion/Fatigue InteractionCorrosion/Fatigue Interaction


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


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


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


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


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


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


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

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