Fatigue Design Assessment - Application and Notations...While fatigue damage is a direct consequence...

ShipRight Design and Construction

Fatigue Design Assessment

Application and Notations

June 2017

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Document History

Document Date: Notes:

September 2014 General release.

June 2015 Consolidated version as identified in ‘Notice 1 – FDA Application and Notations, June 2015 version’.

November 2015 Revisions as identified in ‘Notice 1 – FDA Application and Notations, November 2015 version’.

September 2016 Revisions as identified in ‘Notice 2 – FDA Application and Notations, September 2016 version’.

April 2017 New consolidated version incorporating:

‘Notice 1 – FDA Application and Notations, November 2015 version’, ‘Notice 2 – FDA Application and Notations, September 2016 version’ and minor corrigenda changes.

June 2017 New consolidated version incorporating changes to align Fatigue Design Assessment (FDA) requirements for container ships with those used for other ship types and to align FDA requirements for North Atlantic Wave Environment for all ship types.

© Lloyd's Register Group Limited 2017. All rights reserved. Except as permitted under current legislation no part of this work may be photocopied, stored in a retrieval system, published, performed in public, adapted, broadcast, transmitted, recorded or reproduced in any form or by any means, without the prior permission of the copyright owner. Enquiries should be addressed to Lloyd's Register Group Limited, 71 Fenchurch Street, London, EC3M 4BS.

CHAPTER 1 APPLICATION AND NOTATIONS

SECTION 1 GENERAL

SECTION 2 APPLICATION

SECTION 3 RESPONSIBILITIES

SECTION 4 FATIGUE DESIGN ASSESSMENT (FDA)

SECTION 5 TOOLS AND EQUIPMENT

SECTION 6 REFERENCES

Fatigue Design Assessment - Application and Notations

2 Lloyd's Register

Section1 General

2 Application

3 Responsibilities

4 Fatigue Design Assessment (FDA)

5 Tools and Equipment

6 References

n Section 1 General

1.1 Introduction

1.1.1 Successful performance of a ship's hull structure during its service life is of paramount importance. Sophisticatedstructural analysis techniques permit the designer to confirm that appropriate stress and other acceptance criteria are met andfacilitate the optimisation of hull steelweight distribution.

1.1.2 Such structural optimisation and the more extensive introduction of higher tensile steels mean that greater emphasismust be placed on ensuring the quality of structural detail design. The assurance of adequate fatigue life of items of detail design,particularly in the higher risk regions of the hull structure, is of particular importance.

1.1.3 Fatigue damage can of course lead to failure of the structural element concerned and, in a worst case situation, result inmajor structural failure and the need for extensive ship repairs. While fatigue damage is a direct consequence of cyclic stresses,construction standards and alignment difficulties also play an important part.

1.1.4 Experience of ships in service and the application of finite element analysis techniques enable the early identification ofhigh stress locations and structural joints most at risk.

1.1.5 Lloyd’s Register (hereinafter referred to as LR) recognised that the conventional procedures for determining fatigue lifecontain a number of drawbacks and a need was seen for an explicit Fatigue Design Assessment (FDA) procedure to bedeveloped. Using service experience on existing ships (through LR’s extensive technical database), expertise in structural design,detailed finite element analysis on a variety of structural detail designs and extensive fatigue testing on scale models of elements ofhull structural detail, LR has developed and introduced a multi-level Fatigue Design Assessment (FDA) procedure.

1.1.6 To assist Shipbuilders in the application of the FDA procedure, LR has developed the Structural Detail Design Guide(SDDG) (Ch 1, 6.1 List of References 6.1.1) and direct calculation procedures which incorporate a unique integrated designapproach based on the spectral method of analysis. The direct calculation procedures are supported by the ShipRight PC-basedsoftware, see Software user manual (Ch 1, 6.1 List of References 6.1.2) and FDA Level 3 Guidance on direct calculations (Ch 1,6.1 List of References 6.1.3). Guidance for the assessment of fatigue strength of hull structures against ice loads in way of the icebelt regions for ships navigating in ice is given in Ch 1, 6.1 List of References 6.1.4.

1.1.7 The objective of the FDA procedure, which is applied in addition to normal plan approval, is to obtain an additionalconfidence level in fatigue performance in the configuration and details of the structure.

1.2 Application

1.2.1 The requirements for the ShipRight FDA notation are to be applied on a mandatory basis to new oil tanker and bulkcarrier configurations over 190 metres in length which are not constructed in accordance with the IACS Common Structural Rules(CSR), and to new designs where the ship type, size and structural configuration demand.

1.2.2 When not mandatory, the ShipRight FDA procedure can be applied on a voluntary basis in order to enhance the level ofconfidence in the fatigue performance of the hull structure. The ShipRight FDA ICE notation is applied on a voluntary basis.

1.2.3 The ShipRight Structural Design Assessment (SDA) (see Note) and Construction Monitoring (CM) procedures areapplied in conjunction with the FDA procedure to ensure that all critical highly stressed areas are identified and appropriateconstruction tolerances at critical joints are not exceeded during construction.


Application and Notations Chapter 1Section 1

Lloyd's Register 3

Note Where FDA plus notation is specified to the application of the CSR, the SDA analysis is not required.

1.2.4 For assignment of the ShipRight FDA and ShipRight FDA plus notations for ships not approved in accordance withthe CSR, the scantling requirements in the Rules and Regulations for the Classification of Ships (hereinafter referred to as the Rulesfor Ships) are to be complied with in addition to the applicable requirements indicated in Table 1.1.1 Summary of requirements forShipRight FDA and ShipRight FDA plus notations (new construction) .

1.2.5 For tankers and bulk carriers compliant with CSR, the requirements of the ShipRight FDA plus notation may beapplied on a voluntary basis. In this case, the CSR minimum scantlings are to be met in addition to the applicable requirementsindicated in Table 1.1.1 Summary of requirements for ShipRight FDA and ShipRight FDA plus notations (new construction) forassignment of the ShipRight FDA plus notation.

1.3 Notations

1.3.1 The ShipRight FDA notation may be assigned when an appraisal of the fatigue performance of the hull structure hasbeen made in accordance with this procedure and found to comply with the requirement of 20 years fatigue life based on the100A1 Fatigue Wave Environment (Worldwide) trading pattern. The ShipRight FDA notation is not applicable to ships approvedusing the CSR.

1.3.2 The ShipRight FDA plus notation may be assigned, upon request, when an additional appraisal of the fatigueperformance of selected critical structural arrangements has been made in accordance with this procedure and found to complywith a higher level of fatigue performance than the ShipRight FDA or the CSR for ships approved using these Rules (see Table1.1.1 Summary of requirements for ShipRight FDA and ShipRight FDA plus notations (new construction) for criteria). The notationis to be followed by the number of years that the vessel has been assessed for and the specific trading pattern, either theworldwide or North Atlantic, denoted by the letters WW and NA respectively, e.g. ShipRight FDA plus (25, WW) and ShipRightFDA plus (25, NA). NA denotes North Atlantic and WW denotes the 100A1 Fatigue Wave Environment (Worldwide) tradingpattern for the relevant ship type. These routes are described in Ch 1, 4 Fatigue Design Assessment (FDA).

1.3.3 Where the FDA procedure is applied on a mandatory basis, ships complying with the requirements of this procedure willbe assigned the notation ShipRight FDA.

1.3.4 Where the FDA procedure is applied on a voluntary basis, depending on the level of fatigue performance requested,ships complying with the requirements of this procedure will, at the Owner’s request, be assigned the notation ShipRight FDA orShipRight FDA plus.

1.3.5 The ShipRight FDA ICE notation may be assigned, upon request, as a supplement to the ShipRight FDA orShipRight FDA plus notation, when an additional appraisal of the fatigue performance of the stiffener end connections against iceloads in the ice belt regions has been made and found to comply with the requirement of the ShipRight Procedure (Ch 1, 6.1 Listof References 6.1.4).

1.3.6 The notations will be placed in Column 4 against the ship entry in LR’s Register of Ships, see Pt 1, Ch 2, 2 Character ofclassification and class notations of the Rules for Ships.

1.3.7 A summary of the requirements for ShipRight FDA and ShipRight FDA plus notations for new ships is outlined in Table 1.1.1 Summary of requirements for ShipRight FDA and ShipRight FDA plus notations (new construction) . The requirementsfor ShipRight FDA ICE notation are given in Ch 1, 6.1 List of References 6.1.4.



4 Lloyd's Register

Table 1.1.1 Summary of requirements for ShipRight FDA and ShipRight FDA plus notations (new construction)

Feature FDA FDA plus (years, WW) FDA plus (years, NA)

Notation ShipRight FDA in Column 4 of

Register Book whether applied on a

voluntary or mandatory basis.

ShipRight FDA plus (years, WW) in

Column 4 of Register Book is applied

on a voluntary basis.

ShipRight FDA plus (years, NA) in

Column 4 of Register Book is applied

on a voluntary basis.

Structural

Details

Assessment of fatigue performance, in

association with criteria (1) below,

requires:

(a) Application of FDA Level 1

Structural Detail Design Guide for

all primary structural connections.

(b) Application of FDA Level 2 to all

longitudinal end connections at

deck, inner and outer shell and

longitudinal bulkheads. The FDA

Level 1 Structural Detail Design

Guide may be used for guidance,

in conjunction with FDA Level 2,

in achieving the acceptance

criteria.

(c) Application of FDA Level 3 to

novel structural connections at

the discretion of the responsible

LR office.

Assessment of a higher fatigue

performance, in association with the

criteria in (1) and (2) below, requires:

(a) Application of FDA Level 2 to all



longitudinal bulkheads.

(b) Application of FDA Level 3 to a

selection of primary and/or

secondary structural connections.

The selection process of such

connections is to be agreed with

the responsible LR office. The

minimum structural connections

to be considered are listed in Ch

1, 4.2 Structural Details Requiring

FDA.

Assessment of a higher fatigue

performance, in association with the

criteria in (1) and (2) below, requires:

(a) Application of FDA Level 2 to all



longitudinal bulkheads.

(b) Application of FDA Level 3 to a

selection of primary and/or

secondary structural connections.

The selection process of such

connections is to be agreed with

the responsible LR office. The

minimum structural connections

to be considered are listed in Ch

1, 4.2 Structural Details Requiring

FDA.

Service

Life /

Trading

pattern

For (b) and (c) above:

(1) Not less than 20 years fatigue

life using the 100A1 Fatigue Wave

Environment (Worldwide) for the

relevant ship type.

And, if required,

(2) Owner specified specific

trading pattern(s) additional

assessment, see Note 1.

For (a) and (b) above:

(1) Not less than 25 years fatigue

life using the 100A1 Fatigue Wave

Environment (Worldwide) trading

pattern for the relevant ship type

and size. For ships approved in

accordance with the CSR, the

ShipRight FDA plus (years,

WW) notation may be assigned,

provided that the minimum

requirement of ShipRight FDA

plus (25, NA) is also to be

satisfied, see ShipRight FDA

plus (years, NA).

And, if required,




For (a) and (b) above:

(1) Not less than shown below,

using the wave environment

specified in Ch 1, 4.3 Fatigue

Wave Environment 4.3.10, see

Note 2:

• 20 years fatigue life for ships not

approved in accordance with the

CSR;

• 25 years fatigue life for ships

approved in accordance with the

CSR.

And, if required,




Note 1. (1) above represents minimum requirements for the assignment of

ShipRight FDA plus notations. Actual required fatigue life and additional

trading pattern(s) are to be agreed between the CSR Shipbuilder and Owner.

Where additional assessment is requested based on the Owner specified

specific trading pattern(s).

Note 2. For ShipRight FDA plus (years, NA) notation, the fatigue assessment

is to be based on the assumptions given in Ch 1, 4.3 Fatigue Wave

Environment 4.3.10.



Lloyd's Register 5

Datasheet A datasheet containing the precise technical conditions of the fatigue assessment is to be made available to the Owner

via Class Direct, or in hard copy form, at the Owner’s request.

Assessment

Procedural

Document

• ShipRight FDA – Application and Notations

• ShipRight FDA – Structural Detail Design Guide

• ShipRight FDA Level 2 – Software User Manual

• ShipRight FDA Level 3 – Guidance on direct calculations.

Pre-contract

Consultation

• It is important that the Shipbuilder, in conjunction with LR, consults with the Owner in order to clarify the Owner’s

requirements in respect of ShipRight FDA notation, trading pattern and service life at the earliest possible opportunity in

the pre-contract process.

Note 1. For ships approved in accordance with the CSR, assignment of the notation ShipRight FDA plus requires application of both

the CSR and the requirements of ShipRight FDA plus above. The ShipRight FDA notation is not applicable to ships approved using

the CSR.

Note 2. For ships not approved in accordance with the CSR, assignment of the notation ShipRight FDA requires application of the

requirements of both SDA and CM procedures.

Note 3. For ships not approved in accordance with the CSR, assignment of the notation ShipRight FDA plus requires application of the

requirements of both ShipRight FDA and ShipRight FDA plus above.

n Section 2 Application

2.1 Identification of critical areas

2.1.1 Prior to commencing the application of the FDA procedure, it is necessary to identify those areas and items of structuraldetail at risk of fatigue damage.

2.1.2 Experience with ships in service has enabled LR to provide information to assist the Shipbuilder in determining specificcritical locations within these areas which may be vulnerable to fatigue. Particular emphasis is placed on locations where highstress magnitudes may be anticipated and for which correct alignment is important. This information is presented in the SDDG (Ch1, 6.1 List of References 6.1.1).

2.1.3 The Shipbuilder shall utilise this information in conjunction with the results obtained from the application of the ShipRightSDA procedure to identify those critical areas which warrant close attention when carrying out a fatigue life assessment. Theminimum critical locations to be considered for the assignment of ShipRight FDA and ShipRight FDA plus notations for eachship type are given in Ch 1, 4.2 Structural Details Requiring FDA.

2.2 Carrying out the fatigue life assessment

2.2.1 In applying the FDA procedure, LR requires the Shipbuilder to consider possible levels of assessment as described in Ch 1, 4 Fatigue Design Assessment (FDA) of this document.

2.2.2 In applying the FDA procedure, the Shipbuilder is required to specify and submit details of the intended fabricationtreatments, construction tolerances and defect correction procedures which are required to be utilised in the fatigue lifecalculation. It is therefore necessary to ensure that these specified treatments, tolerances and correction procedures are compliedwith during the actual ship construction for the identified critical joints. This is carried out through the application of the CMprocedure (see Ch 1, 1 General of this document for further details). Further guidance on fabrication treatments, constructiontolerances and defect correction procedures is given in Chapters 2 and 3 of the SDDG (Ch 1, 6.1 List of References 6.1.1).

2.2.3 As indicated previously, LR has developed PC-based software to assist the Shipbuilder in carrying out the FDA Level 2assessment. A theoretical description of this procedure is given in LR’s FDA Level 2 – Software user manual, see Ch 1, 6.1 List ofReferences 6.1.2.

2.2.4 The FDA Level 2 software is available to designers and the software considers the end connections of the hull girderlongitudinal stiffeners.



6 Lloyd's Register

n Section 3 Responsibilities

3.1 The Shipbuilder

3.1.1 The Shipbuilder is required to carry out the FDA calculations in accordance with the ShipRight FDA procedure.

3.1.2 The Shipbuilder, in conjunction with LR, shall consult with and obtain from the Shipowner, the specification for the ship’strading pattern and service life criteria. Requirement for notation should be confirmed, i.e. standard ShipRight FDA notation with100A1 Fatigue Wave Environment (Worldwide) trading pattern and 20 years service life or ShipRight FDA plus notation with ahigher specification (see Table 1.1.1 Summary of requirements for ShipRight FDA and ShipRight FDA plus notations (newconstruction) for guidance). Where the ShipRight FDA ICE notation is requested, the expected ice conditions for the specifiedtrading routes shall also be provided.

3.2 Lloyd's Register

3.2.1 Lloyd’s Register shall:

(a) In consultation with the Shipbuilder, agree the assessment level(s) to be applied.

(b) In consultation with the Shipbuilder, agree whether the specification for trading pattern and fatigue life criteria is to complywith the ShipRight FDA notation, i.e. 100A1 Fatigue Wave Environment (Worldwide) trading pattern and 20 years service life,or ShipRight FDA plus notation, i.e. a higher specification.

(c) In consultation with the Shipbuilder, agree on the trading routes, ice conditions and fatigue life criteria for the ShipRight FDAICE notation where requested.

(d) Approve the results of the Shipbuilder's calculations.

(e) Approve the construction tolerances and fabrication treatments for the critical joints and evaluate the proposed sequencesfor welding, fabrication and erection, as appropriate.

(f) Ensure that the approved construction tolerances and details fabrication treatments are incorporated into the ShipRight CMplan.

(g) Ensure that the critical joints are highlighted on the relevant approved structural plans and incorporated in the CM plan,thereby drawing their attention to the Shipbuilder and to the LR Surveyors.

n Section 4 Fatigue Design Assessment (FDA)

4.1 FDA Procedure

4.1.1 In applying the FDA procedure, LR requires the Shipbuilder to consider three possible levels of assessment as follows:

(a) Level 1. The proposed joint configurations at critical areas are compared with the structural design configurations specified inthe Structural Detail Design Guide, which can offer an improved fatigue life performance.

(b) Level 2. This is a spectral direct calculation procedure based on simplified structural models which utilises LR's PC-Windowsbased software. This procedure has been derived from experience in applying the Level 3 fatigue assessment and is intendedfor the analysis of secondary stiffener connections.

(c) Level 3. This is a full spectral direct calculation procedure based on first principles computational methods, such ashydrodynamic load and ship motion analysis, and finite element analysis. It is intended mainly for the analysis of primarystructural details.

4.1.2 Where a ShipRight FDA notation or one of the ShipRight FDA plus notations is requested, the FDA Level 1 minimumdetail design improvement specified in the SDDG is to be complied with for all primary structural connections unless a satisfactoryfatigue life has been predicted by an FDA Level 3 analysis. For alternative arrangement of primary structural connections, or forship types not included in the SDDG, special consideration will be given by LR for the need to apply a FDA Level 3 assessment.

4.1.3 The FDA direct calculation procedures are applicable to structural details within the cargo space region and itsintegration with other regions of the ship, which are subjected to the action of low frequency wave-induced loads. The assessmentof the fatigue performance of structural details subjected to cyclic loading caused by the propeller or any other mechanical/hydraulically-induced vibrations is not covered by the procedures. For fatigue assessment due to high frequency wave-induced



Lloyd's Register 7

springing responses, see Pt 4, Ch 8,14.3 Procedures for verification of structural response due to whipping, springing and fatigueof the Rules for Ships and Ch 1, 6.1 List of References 6.1.5.

4.2 Structural Details Requiring FDA

4.2.1 The structural details and locations required to be assessed by FDA Level 2 and FDA Level 3 procedures are describedin this Section.

4.2.2 Longitudinal End Connections

The fatigue performance of all longitudinal end connections at deck, inner and outer shell and longitudinal bulkheads to transversestructure are to be assessed for the assignment of ShipRight FDA and ShipRight FDA plus notations. The fatigue assessmentmay be based on either FDA Level 2 or FDA Level 3 analyses.

4.2.3 Structural Details requiring FDA Level 3 assessment

(a) Oil and Product Tankers. For oil and product tankers complying with the requirements of the CSR, the Shipright FDAnotation is not applicable. For oil and product tankers above 190m in length not complying with the requirements of the CSR,the ShipRight FDA notation is mandatory. The structural details required to be assessed for the assignment of FDA,ShipRight FDA plus (years, WW) and ShipRight FDA plus (years, NA) notations are given in Table 1.4.1 Oil and producttanker structural details for fatigue assessment.

(b) Bulk Carriers. For bulk carriers complying with the requirements of the CSR, the ShipRight FDA notation is not applicable.For bulk carriers above 190m in length not complying with the requirements of the CSR, the ShipRight FDA notation ismandatory. The structural details required to be assessed for the assignment of FDA, ShipRight FDA plus (years, WW) andShipRight FDA plus (years, NA) notations are given in Table 1.4.2 Bulk Carrier structural details for fatigue assessment.

(c) Container Ships. The FDA notation is mandatory for Container Ships where one or more of the following criteria applies:

(i) structural members that contribute to the ship’s longitudinal strength constructed with high tensile steel, where a KL

factor of 0,66 is to be used with material yield stress 390 N/mm2 or a KL factor of 0,62 is to be used with material yieldstress 460 N/mm2, see Pt 3, Ch 2, 1.2 Steel 1.2.5 of the Rules for Ships.

(ii) condition specified in Pt 4, Ch 8, 14.3 Procedures for verification of structural response due to whipping, springing andfatigue 14.3.2 of the Rules for Ships applies, in which case, the fatigue assessment is to include effect of hull girderspringing. Otherwise, the FDA procedure is optional. The assignment of the ShipRight FDA notation or any of theShipRight FDA plus notations requires fatigue assessment of the structural details listed in Table 1.4.3 Container Shipstructural details for fatigue assessment.

(d) LNG Carriers. For LNG carriers the FDA procedure is optional. For membrane LNG carriers, the assignment of theShipRight FDA notation or any of the ShipRight FDA plus notations requires fatigue assessment of the structural detailslisted in Table 1.4.4 Membrane Tank LNG Carrier structural details for fatigue assessment. For other types of LNG carriers thestructural details to be investigated for the assignment of the ShipRight FDA notation or any of the ShipRight FDA plusnotations are to be specially agreed with LR.

(e) LPG Carriers. For LPG carriers the FDA procedure is optional. The structural details required to be assessed for theassignment of ShipRight FDA, FDA plus (years, WW) and ShipRight FDA plus (years, NA) notations for Type A andType C LPG carriers are given in Table 1.4.5 LPG Carrier structural details for fatigue assessment.

(f) Other Ship Types. For ship types not specifically mentioned in this document the application of the FDA procedure isoptional. The extent of fatigue analysis required to be carried out for the assignment of the ShipRight FDA notation or any ofthe ShipRight FDA plus notations is to be specially agreed with LR.



8 Lloyd's Register

Table 1.4.1 Oil and product tanker structural details for fatigue assessment

Oil & Product Tanker Structural Details

ID STRUCTURAL DETAIL

1. Connection of side, inner and outer bottom shell, longitudinal bulkhead, hopper and topside, deck

longitudinal stiffeners to transverse structure.

2. Hopper connection to double bottom structure.

The analysis is to consider the connection between:

(a) inner bottom plating and hopper sloping plate: weld toes on inner bottom,

(b) inner bottom plating and hopper sloping plate: weld toes on hopper sloping plate,

(c) transverse web frame plating and inner bottom plating,

(d) transverse web frame plating and hopper sloping plate,

(e) transverse web frame plating and radius knuckle plate, if applicable,

(f) transverse web frame plating and longitudinal girder plating,

(g) transverse web frame plating and stringer plating, if applicable,

(h) ends of inner bottom scarphing brackets, if applicable,

(i) critical details of transverse brackets in tanks, if fitted.

The analysis is to be carried out at:

• web frame location closest to mid tank location of midship cargo tank (if tank has a wash bulkhead

then the web frame closest to midway between wash bulkhead and oil-tight transverse bulkhead is

to be used).

3. Hopper connection to side structure.


(a) outer longitudinal bulkhead (inner skin) plating and hopper sloping plate,

(b) transverse web frame plating and outer longitudinal bulkhead (inner skin) plating,

(c) transverse web frame plating and hopper sloping plate,

(d) transverse web frame plating and radius knuckle plate, if applicable,

(e) transverse web frame plating and stringer plating,

(f) critical details of transverse brackets in tanks, if fitted.


• web frame location closest to mid tank location of midship cargo tank (if tank has a wash bulkhead

then the web frame closest to midway between wash bulkhead and oil-tight transverse bulkhead is

to be used).



Lloyd's Register 9

4. Plane oil-tight bulkheads, if fitted.

The connection of transverse oil-tight bulkhead to side water ballast tank on forward and aft sides of

bulkhead at each stringer level.


(a) oil-tight transverse bulkhead plating and outer longitudinal bulkhead (inner skin) plating,

(b) oil-tight transverse bulkhead stringer connection to outer longitudinal bulkhead (inner skin) plating

(heel and toe locations),

(c) web frame (or watertight bulkhead plating connection) to outer longitudinal bulkhead (inner skin)

plating,

(d) web frame (or watertight bulkhead) plating connection to side stringer plating,

(e) side stringer plating connection to outer longitudinal bulkhead (inner skin) plating,

(f) if reverse brackets (backing brackets) are fitted at the connection of the bulkhead plating to the outer

longitudinal bulkhead (inner skin) plating, the analysis is to consider the following:

• bracket toe and oil-tight bulkhead plating in way of the connection

• bracket heel and oil-tight bulkhead plating in way of the connection if a scallop or cut-out is fitted

• free edge of bracket

• end of bracket face plate, if fitted.

The analysis is to be carried out at an oil-tight transverse bulkhead location of the midship cargo tank.

5. Corrugated oil-tight bulkheads, if fitted:

(a) the connection of transverse oil-tight bulkhead plating to outer longitudinal bulkhead (inner skin)

plating at each side stringer level,

(b) connection of vertical corrugations to stool top plate, if stool fitted, or inner bottom for designs

without stools,

(c) supporting brackets and carlings in stool space, if stool fitted,

(d) supporting brackets and carlings in double bottom,

(e) connection of stool top plate to stool plating, if stool fitted,

(f) connection of stool plating to inner bottom, if stool fitted,

(g) connections of shedder plates or gusset plates,

(h) connection of transverse bulkhead stool to longitudinal bulkhead stool, if applicable.

The analysis is to be carried out:

• for longitudinal bulkheads at a mid tank location of midship cargo tank

• for transverse oil-tight bulkhead location of midship cargo tank.

Note 1. Item 1 is required to be assessed for the assignment of ShipRight FDA or ShipRight FDA plus notation, using either an FDA

Level 2 or an FDA Level 3 analysis.

Note 2. Items 2 to 5 are to be assessed by means of an FDA Level 3 analysis for the assignment of ShipRight FDA plus notation.

Note 3. Other structural connections may be required at the discretion of the responsible LR office.

Note 4. ShipRight FDA Notation is not applicable to oil tankers approved in accordance with the CSR.



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Table 1.4.2 Bulk Carrier structural details for fatigue assessment

Bulk Carrier Structural Details


1. Connection of side, inner and outer bottom shell, longitudinal bulkhead, hopper and topside, deck

longitudinal stiffeners to transverse structure.

2. Hopper connection to double bottom structure.


(a) inner bottom plating and hopper sloping plate,

(b) transverse web frame plating and inner bottom plating,



(e) transverse web frame plating and longitudinal girder plating,

(f) transverse web frame plating and stringer plating, if applicable,

(g) ends of inner bottom scarphing brackets, if applicable,

(h) critical details of transverse brackets in tanks, if fitted.


• web frame location closest to mid tank location of an ordinary cargo hold, heavy cargo hold (if fitted)

and heavy ballast hold (if fitted) in or closest to midships.

• transverse bulkhead location of ordinary cargo hold, heavy cargo hold (if fitted) and heavy ballast

hold (if fitted) in or closest to midships.

3. Hopper connection to side structure (double hull bulk carrier).






(e) transverse web frame plating and stringer plating,

(f) critical details of transverse brackets in tanks, if fitted.


• web frame location closest to mid tank location of a ballast hold (if fitted) in or closest to midships.

4. Transverse bulkhead lower stool connection to double bottom structure.


(a) inner bottom plating and stool sloping plate,

(b) stool internal web and inner bottom plating,

(c) stool internal web and sloping plate,

(d) stool internal web and double bottom girder/floor,

(e) transverse web frame plating and stringer plating, if applicable,

(f) critical details of transverse bracket inside stool, if fitted.


• transverse bulkhead location of ordinary cargo hold, heavy cargo hold (if fitted) and heavy ballast

hold (if fitted) in or closet to midships.



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5. Corrugated transverse bulkheads to lower stool connection, if fitted.

(a) connection of vertical corrugations to lower stool top plate,

(b) supporting brackets and carlings in stool space, if fitted,

(c) connection of stool top plate to stool plating,

(d) connections of shedder plates or gusset plates.


• web frame location closest to mid tank location of a ballast hold (if fitted) in or closest to midships.

6. Hatchway corners and longitudinal hatch coaming end brackets of:

(a) the aft most cargo hold forward of the engine room,

(b) an ordinary cargo hold cargo hold at or closet to midships,

(c) a heavy cargo hold (if fitted) at or closest to midships,

(d) a heavy ballast hold (if fitted) at or closest to midships,

(e) No. 1 cargo hold.

7. Upper and lower side frame end bracket connections at mid hold of an ordinary cargo hold, heavy cargo

hold (if fitted) and heavy ballast hold (if fitted) in or closest to the midship region on single hull bulk

carriers.



Note 2. Items 2 to 7 are to be assessed by means of an FDA Level 3 analysis for the assignment of ShipRight FDA plus notation.


Note 4. ShipRight FDA Notation is not applicable to bulk carriers approved in accordance with the CSR.

Table 1.4.3 Container Ship structural details for fatigue assessment

Container Ship Structural Details


1. Connection of side, inner and outer bottom shell, longitudinal bulkhead and deck longitudinal stiffeners to

transverse structure.

2. Connection of longitudinal stiffeners to transverse primary structure in way of partial decks or stringers.

3. Connection of typical cross-deck box structure to side structure including hatchway corners at hatch

coaming top, upper deck passage way and bottom of cross-deck structure. Hatchway corners at the

forward region.

4. Hatchway corners forward of the engine room and in way of the connection of engine room to container

holds aft of the engine room.

5. Hatchway corners at the connection of container holds to closed sections for fuel oil tanks or in way of

accommodation blocks not above the engine room.

6. End of longitudinal coaming in way of engine casing or accommodation block, if applicable.

7. Connections of coaming top plate in way of changes in height of the coaming top plate.

8. Integration of superstructure into the side coaming, if applicable.



12 Lloyd's Register

9. Location of high stress gradients identified from the SDA analysis.

Note 1. Items 1 and 2 are required to be assessed for the assignment of ShipRight FDA or ShipRight FDA plus notation, using either

an FDA Level 2 or an FDA Level 3 analysis.

Note 2. Items 3 to 9 are to be assessed by means of an FDA Level 3 analysis for the assignment of ShipRight FDA or ShipRight FDA

plus notation.


Table 1.4.4 Membrane Tank LNG Carrier structural details for fatigue assessment

Membrane Tank LNG Carrier Structural Details


1. Connection of side, inner and outer bottom shell, longitudinal bulkhead, hopper and topside, upper and

trunk deck longitudinal stiffeners to transverse structure.

2. Lower hopper lower knuckle





(d) transverse web frame plating and longitudinal girder plating,


(f) ends of inner bottom extension brackets, if applicable.

The analysis is to be carried out at mid-length of a midship cargo tank.

3. Lower hopper upper knuckle





(d) transverse web frame plating and stringer plating,


4. Cofferdam bulkhead to inner bottom connections

(a) between Nos. 1 & 2 tanks,

(b) between Nos. 2 & 3 tanks,

(c) between the aft-most tank and engine room.

5. Cofferdam bulkhead to side structure connections

(a) between Nos. 1 & 2 tanks,

(b) between Nos. 2 & 3 tanks,

(c) at forward end of No. 1 tank,

(d) between the aft-most tank and engine room.

6. Scarphing of trunk deck and sides into the superstructure and engine room.

The analysis is to consider the following:

(a) ends of sweep brackets,

(b) windows and door openings in region of stress flow.

7. Connection of trunk deck scarphing brackets at forward region.



Lloyd's Register 13

8. Liquid Dome Opening (not required for NO96 designs or similar)

The analysis is to consider the following:

(a) Corners of openings in:

• Outer trunk deck plating

• Inner trunk deck plating

(b) Coaming bracket ends

The analysis is to be carried out for the liquid dome opening closest to midships.




plus notation.


Table 1.4.5 LPG Carrier structural details for fatigue assessment

LPG Carrier Structural Details


1. Connection of side, inner and outer bottom shell, longitudinal bulkhead, hopper and topside, upper and

trunk deck longitudinal stiffeners to transverse structure.

2. Lower hopper lower knuckle





(d) transverse web frame plating and longitudinal girder plating,


(f) ends of inner bottom extension brackets, if applicable.


3. Upper and lower side frame end bracket connections at mid-length of a midship cargo tank.

4. Dome opening in way of a midship tank, including end of coaming brackets, if fitted.

5. Chocks and cradle supports.




plus notation.


4.3 Fatigue Wave Environment

4.3.1 FDA 100A1 Fatigue Wave Environment (Worldwide)

For the assignment of ShipRight FDA and ShipRight FDA plus notations, LR has derived FDA 100A1 Fatigue WaveEnvironment (Worldwide) trading patterns for specific ship types, using worldwide trading statistics. These trading patterns, whichare made up of a number of relevant routes, are used in the spectral fatigue direct calculation for the FDA Level 2 and Level 3assessments. For all trading patterns, default or otherwise, the probability of encountering a particular sea condition and waveheading is obtained from a voyage simulation program which makes use of global wave statistical data.



14 Lloyd's Register

4.3.2 In general, the service speed to be used for FDA calculation is taken as 90 per cent of the maximum service speed asdefined in the Rules for Ships, Part 3 Ship Structures (General). For ships designed with large sea-margins, the percentage ofmaximum service speed to be used for FDA calculations will be specially considered.

4.3.3 Ship designers/Shipbuilders are required to provide details (e.g. trim and stability calculations) of the required loadingconditions for performing the FDA calculation. In general, loading conditions best representing the intended trading operationshould be used. Departure conditions (i.e. all fuel tanks are full and full bunkers) are to be considered.

4.3.4 For ship types not specified in this Section, the FDA Fatigue Wave Environment will be specially considered by LR.

4.3.5 Oil Tankers

A fully loaded condition and a ballast condition are considered. For each trading route, it is assumed that a ship firstly sails fromthe importing port/area to the exporting port/area in ballast, and then returns to the importing port/area fully loaded.

The FDA Fatigue Wave Environment (Worldwide) 100A1 trading patterns are summarised in Table 1.4.6 100A1 Fatigue WaveEnvironment (Worldwide) trading patterns for crude oil tankers and Table 1.4.7 100A1 Fatigue Wave Environment (Worldwide)trading patterns for product oil tankers.

4.3.6 Bulk Carriers

Fully loaded conditions and ballast conditions are considered. For bulk carriers strengthened for carrying heavy cargo in alternateholds an alternate-hold fully loaded condition should be used for iron ore trading routes. In general, the trading pattern assumesthat a ship firstly sails from the importing port/area to the exporting port/area in ballast and then returns to the importing port/areafully loaded, with the exception of handy size bulk carriers which operate on a number of round trip routes in which the ship isassumed to be fully loaded for the whole trip.

Two ballast conditions, light ballast and heavy ballast, are considered. For handy size bulk carriers, the utilisation is assumed to be50 per cent in heavy ballast condition and 50 per cent in light ballast condition. For other sizes of bulk carriers the utilisation of 60per cent heavy ballast and 40 percent light ballast is assumed. The FDA Fatigue Wave Environment (Worldwide) 100A1 tradingpatterns for bulk carriers are summarised in Table 1.4.8 100A1 Fatigue Wave Environment (Worldwide) trading patterns for bulkcarriers.

4.3.7 Liquefied Gas Carriers

A fully loaded condition and a ballast condition are considered. The trading pattern assumes that a ship firstly sails from theimporting port/area to the exporting port/area in ballast, and then returns to the importing port/area fully loaded.

The FDA Fatigue Wave Environment (Worldwide) 100A1 trading patterns are summarised in Table 1.4.9 100A1 Fatigue WaveEnvironment (Worldwide) trading patterns for LNG carriers and Table 1.4.10 100A1 Fatigue Wave Environment (Worldwide) tradingpatterns for LPG carriers.

4.3.8 Ore Carriers

A fully loaded condition and a ballast condition are considered. For each trading route, it is assumed that a ship firstly sails fromthe importing port/area to the exporting port/area in ballast,and then returns to the importing port/area fully loaded.

The FDA Fatigue Wave Environment (Worldwide)100A1 trading patterns for ore carriers are summarised in Table 1.4.11 100A1Fatigue Wave Environment (Worldwide) trading patterns for ore carriers.

4.3.9 Container Ships

Container Ships usually trade in loaded conditions. Ballast conditions are rarely used. Therefore, ballast conditions are omitted forFDA purpose. Two loaded conditions are considered for the FDA analysis. These conditions are summarised in Table 1.4.12Loading conditions for Fatigue Design Assessment of Container Ships.

The amount of ballast water carried is to be minimum provided that the longitudinal strength, stability and other operationalrequirements are satisfied.

The FDA Fatigue Wave Environment (Worldwide) 100A1 trading patterns for Container Ships are summarised in Table 1.4.13100A1 Fatigue Wave Environment (Worldwide) trading patterns for container ships.

4.3.10 North Atlantic Wave Environment

For the assignment of ShipRight FDA plus (years, NA) notation, the Level 2 and Level 3 spectral fatigue assessments are to bebased on the loading condition utilisation, wave environment and assumptions specified in Table 1.4.14 Fatigue Wave Environment(North Atlantic) trading patterns and loading condition utilisation for ShipRight FDA plus (years, NA) notation.

Loading conditions for ship types not specified in the table will be specially considered.



Lloyd's Register 15

Table 1.4.6 100A1 Fatigue Wave Environment (Worldwide) trading patterns for crude oil tankers

Ship Type/

Group

Trading Route

Exporting Area Importing Area % of

service life

Very large

crude oil

tanker

(VLCC)

200,000 dwt

and above

W Asia (Persian Gulf, Ras Tanura)




N Europe (North Sea, UK/Norway)

E Asia (Taiwan)

E Asia (Japan, Yokohama)

N America (Gulf of Mexico, New Orleans)

W Europe (Rotterdam)

N America (USA EC, New York)

17,0

30,0

28,0

21,0

4,0

Suezmax

crude oil

tanker

125,000-

200,000 dwt

E Europe (Black Sea)

S America (Venezuela)






N America (Alaska)

W Africa (Nigeria, Bonny)



W Europe (Med, Marseille)




N America (USA WC, Los Angeles) via Pacific Ocean

W Europe (Med, Marseille) via Cape

Australasia (Adelaide)

N America (USA WC, Los Angeles)




8,2

6,8

6,7

16,3

4,3

9,1

6,6

5,8

24,8

6,8

4,6

Aframax

crude oil

tanker

80,000-

125,000 dwt





N Africa (Libya)







SE Asia (Indonesia, Ardjuna)

N America (Alaska)


N America (USA WC, New Orleans)


S America (Brazil, Santos)




E Asia (Taiwan)

S Asia (India, Madras)

Australasia (Adelaide)



N America (USA WC, Los Angeles)

9,4

24,9

2,2

6,9

4,5

5,1

24,4

5,4

2,5

2,0

7,5

2,4

2,8



16 Lloyd's Register

Panamax

crude oil

tanker

50,000-

80,000 dwt

N Europe (Latvia, Ventspils)




N Africa (Libya)














8,8

5,3

27,0

28,3

8,1

3,7

10,5

2,1

6,2

Handy crude

oil tanker

5,000-

50,000 dwt





N Africa (Libya)

E Asia (China, Qingdao)









13,0

5,0

24,8

38,5

9,4

1,9

7,4

Table 1.4.7 100A1 Fatigue Wave Environment (Worldwide) trading patterns for product oil tankers

Ship Type/Group Trading Route


service life

Aframax oil product

tanker 80,000-

125,000 dwt


N Africa (Libya)












E Asia (Taiwan)


E Asia (Singapore)

W Europe (Rotterdam) via Suez

N America (USA EC, New York) via Suez


S America (Brazil, Santos) via Cape

2,0

9,2

12,2

7,7

28,4

16,7

5,0

9,9

3,0

5,9



Lloyd's Register 17

Panamax oil

product tanker

50,000- 80,000

dwt





N Africa (Libya)

N America (USA EC, Houston)





















E Asia (Taiwan)



S Africa (South Africa, Durban)

SE Asia (Singapore)



W Europe (Rotterdam) via Suez



E Asia (Taiwan)


5,1

2,1

6,4

12,0

3,2

5,6

14,2

1,6

7,2

4,3

3,8

2,9

4,3

4,2

1,3

1,5

4,4

13,6

2,3

Handy oil product

tanker 5,000-

50,000 dwt






N Africa (Libya)






















E Asia (Taiwan)



S Africa (South Africa, Durban)

E Asia (Taiwan)





E Asia (Taiwan)


5,1

2,1

6,5

12,2

1,6

2,9

5,7

14,4

1,7

7,3

4,1

3,9

5,0

4,2

1,1

1,3

4,0

14,7

2,2



18 Lloyd's Register

Table 1.4.8 100A1 Fatigue Wave Environment (Worldwide) trading patterns for bulk carriers

Ship

Type/Group

Trading Route

Cargo Exporting Area Importing Area % of

service life

Capesize

bulk carrier

80,000 dwt

and above

Iron

Ore

61%

Australasia (W Australia, Dampier)

Australasia (W Australia, Walcott)


N America (Canada, Sept Isles)

S Asia (India, Mormugao)

S America (Brazil, Tubarao)


S America (Tubarao, Brazil)



E Asia (China, Shanghai)

W Europe (Belgium, Antwerp)



E Asia (Japan, Yokohama) via Indian Ocean

E Asia (Taiwan) via Indian Ocean

6,2

10,1

7,1

1,8

2,4

8,2

12,1

13,1

Coal

39%Australasia (NSW, Newcastle)

Australasia (NSW, Newcastle)

Australasia (NSW, Port Kembla)

N America (Canada, Vancouver)

S Africa (South Africa, Richard’s Bay)



N America (USA EC, Baltimore)



E Asia (Taiwan)




E Asia (Taiwan)


E Asia (Taiwan)


9,9

4,3

4,8

4,0

1,9

2,9

4,0

2,4

4,8

Panamax

bulk carrier

50,000-

80,000 dwt

Iron

Ore

20%













2,0

3,9

2,3

2,7

4,4

4,7

Coal


Australasia (NSW, Newcastle)

Australasia (NSW, Port Kembla)

N America (Canada, Vancouver)







E Asia (Taiwan)




E Asia (Taiwan)


E Asia(Taiwan)


11,4

5,0

5,6

4,6

2,2

3,3

4,6

2,8

5,5

Grain

35%N America (Canada, Vancouver)

S America (Argentina, Rosario)

N America (USA EC, Charleston)


N America (Gulf of Mexico, Florida, Freeport)

N America (USA WC, San Francisco)

E Asia (Taiwan)



W Africa (Nigeria, Lagos)

E Asia (Taiwan) via Panama


2,6

2,0

4,0

1,2

16,5

8,7



Lloyd's Register 19

Handy bulk Iron

Ore

16%



S America (Venezuela, Puerto Ordaz)

S America (Peru, San Nicolas)







4,4

1,3

2,6

2,0

5,7

Coal


E Asia (China, Qinhuangdao)

S America (Venezuela, Maracaibo)








10,8

3,0

4,6

15,6

5,0

Grain




N America (USA WC, San Francisco)

E Asia (Taiwan)




10,9

7,8

18,8

7,5

Table 1.4.9 100A1 Fatigue Wave Environment (Worldwide) trading patterns for LNG carriers

Ship Type/

Group

Trading Route


service

life

LNG carrier W Asia (Persian Gulf, Qatar, Ras Laffan)

W Asia (Persian Gulf, Qatar, Ras Laffan)




SE Asia (Indonesia, Bontang)


N Europe (North Sea, Norway, Snohvit)

N America (USA, Gulf of Mexico)

E Asia (Japan, Tokyo)

N Europe (UK, Milford Haven) via Suez

N America (USA EC, Boston) via Suez

N America (USA Gulf of Mexico, Louisiana) via Suez



N Europe (UK, Milford Haven)

N America (USA EC, Boston)

E Asia (China, Shanghai) via Panama

16,0

10,0

9,0

9,0

10,0

17,0

16,0

9,0

4,0



20 Lloyd's Register

Table 1.4.10 100A1 Fatigue Wave Environment (Worldwide) trading patterns for LPG carriers

Ship Type/

Group

Trading Route

Exporting Area Importing Area % of life

service

LPG carrier W Asia (Persian Gulf, Ras Tanura)





N Africa (Algeria)

N Africa (Algeria)

N Europe (North Sea)

N Europe (North Sea, Norway)





E Asia (China, Qingdao)

E Asia (South Korea)


E Asia (South Korea)

C America (Mexico)


W Asia (Med, Turkey)

N America (USA EC, Philadelphia)




12,5

26,7

10,8

2,5

2,5

11,7

10,0

6,7

6,7

2,5

5,0

2,4

Table 1.4.11 100A1 Fatigue Wave Environment (Worldwide) trading patterns for ore carriers

Ship

Type/Group

Trading Route


service

life

Very Large Ore

carrier (VLOC)

300,000 dwt

and above




S America (Brazil, Sao Luis)





E Asia (Japan, Oita)



E Asia (Japan, Oita)

SE Asia (Philippines, Villanueva)

E Asia (China, Qingdao/Shanghai)

2,5

2,5

5,0

5,0

11,0

4,0

70,0

Very Large Ore

carrier (VLOC)

less than

300,000 dwt

and Capesize

Ore carrier

80,000-

200,000 dwt





S Asia (India, Mormugao)







W Europe (Antwerp)





10,2

16,6

11,6

3,0

3,9

13,4

19,8

21,5



Lloyd's Register 21

Panamax Ore

carrier 50,000-

80,000 dwt













10,0

19,5

11,5

13,5

22,0

23,5

Handy Ore

carrier 5,000-

50,000 dwt



S America (Venezuela, Puerto Ordaz)

S America (Peru, San Nicolas)



N America (USA EC, New Orleans)


E Asia (Taiwan)


27,5

8,1

16,3

12,5

35,6

Table 1.4.12 Loading conditions for Fatigue Design Assessment of Container Ships

FDA Loading condition ID FDA Loading condition

Loaded TEU weight

(tonne/TEU)

Ship draught1

(midship)

< 500 TEU Container Ship

FDA LC 1.1

FDA LC 1.2

10,0

8,0

1,00 to 1,05 of design draught


500 TEU - 1,500 TEU Container Ship

FDA LC 2.1

FDA LC 2.2

10,0

8,0



1,500 TEU- 3,000 TEU Container Ship

FDA LC 3.1

FDA LC 3.2

12,0

10,0



3,000 TEU - 5,000 TEU Container Ship

FDA LC 4.1

FDA LC 4.2

12,0

10,2



> 5,000 TEU Container Ship

FDA LC 5.1

FDA LC 5.2

12,0

10,0



Note 1. Ships are loaded homogeneously.



22 Lloyd's Register

Table 1.4.13 100A1 Fatigue Wave Environment (Worldwide) trading patterns for container ships

Route Description Port Information FDA loading condition % of

service lifeTypical Port Rotation Port time,

see Note 1

(Days)

< 500 TEU Container Ship

N Asia round trip Pusan, Tokyo, Shanghai, Dalian,

Qingdao, Pusan3,3 FDA LC1.1 33,0

SE Asia round trip Singapore, Bangkok, Saigon, Jakarta,

Singapore2,9 FDA LC1.1 34,3

Mediterranean Intra/Feeder round trip Gioia Tauro, La Spezia, Genoa,

Barcelona, Malta, Gioia Tauro4,2 FDA LC1.1 11,6

N Europe/Baltic round trip Hamburg, Helsinki, Gdansk, Hamburg 3,5 FDA LC1.2 11,5

Caribbean/Central America round trip Kingston, Freeport, Miami, Freeport,

Panama, Kingston6,0 FDA LC1.2 9,6

500 TEU - 1,500 TEU Container Ship

Intra Asia Long Haul round trip Singapore, Shanghai, Pusan, Tokyo,

Kobe, Pusan, Singapore3,7 FDA LC2.1 38,5

SE Asia round trip Singapore, Bangkok, Jakarta,

Singapore3,2 FDA LC2.1 28,6

N Europe/Baltic round trip Hamburg, Helsinki, Riga, Gdansk,

Hamburg4,2 FDA LC2.2 9,9

Mediterranean Intra/Feeder round trip Gioia Tauro, La Spezia, Genoa,

Valencia, Malta, Gioia Tauro5,6 FDA LC2.1 8,6

N America to S America New York, Miami, Kingston, Santos, Rio

Grande, Buenos Aires3,0 FDA LC2.1 7,2

S America to N America Buenos Aires, Rio Grande, Santos,

Kingston, Miami, New York3,0 FDA LC2.1 7,2


Transatlantic to St. Lawrence Antwerp, Le Havre, Montreal 1,6 FDA LC3.2 6,6

St. Lawrence to Transatlantic Montreal, Le Havre, Antwerp 1,6 FDA LC3.1 6,6

N Europe to N America-Caribbean Felixstowe, Antwerp, Norfolk, Miami,

Freeport, Kingston2,8 FDA LC3.2 4,7

Caribbean to N America-N Europe Kingston, Freeport, Miami, Norfolk,

Antwerp, Felixstowe2,8 FDA LC3.2 4,7

Africa to N Europe Durban, Cape Town, Antwerp,

Rotterdam, Felixstowe2,9 FDA LC3.1 8,3

N Europe to Africa Felixstowe, Rotterdam, Antwerp, Cape

Town, Durban2,9 FDA LC3.2 8,3

Europe to Australasia Hamburg, Felixstowe, Rotterdam, Le

Havre, Melbourne, Sydney4,3 FDA LC3.2 8,4



Lloyd's Register 23

Australasia to Europe Sydney, Melbourne, Le Havre,

Rotterdam, Felixstowe, Hamburg4,3 FDA LC3.1 8,4

Intra Asia Long Haul Singapore, Kaohsiung, Pusan, Kobe 2,7 FDA LC3.2 17,0

Mediterranean to Asia Barcelona, Genoa, Jeddah, Colombo,

Klang, Singapore, Bangkok, Hong Kong3,4 FDA LC3.1 9,5

Asia to Mediterranean Hong Kong, Bangkok, Singapore,

Klang, Colombo, Jeddah, Genoa,

Barcelona

3,4 FDA LC3.2 9,5

N America to Mediterranean Savannah, New York, Algeciras,

Barcelona, Genoa2,9 FDA LC3.2 4,0

Mediterranean to N America Genoa, Barcelona, Algeciras, New York,

Savannah2,9 FDA LC3.1 4,0


Transatlantic Westbound Hamburg, Felixstowe, Rotterdam,

Halifax, New York, Norfolk

3,7 FDA LC4.2 13,1

Transatlantic Eastbound Norfolk, New York, Halifax, Rotterdam,

Felixstowe, Hamburg

3,7 FDA LC4.2 13,1

Transpacific Eastbound Kaohsiung, Pusan, Yokohama, Tacoma,

Los Angeles

4,2 FDA LC4.2 14,0

Transpacific Westbound Los Angeles, Tacoma, Yokohama,

Pusan, Kaohsiung

4,2 FDA LC4.1 14,0

Mediterranean to Asia Barcelona, Genoa, Gioia Tauro, Klang,

Singapore, Bangkok, Hong Kong,

Shanghai

5,3 FDA LC4.1 8,5

Asia to Mediterranean Shanghai, Hong Kong, Bangkok,

Singapore, Klang, Gioia Tauro, Genoa,

Barcelona

5,3 FDA LC4.2 8,5

Asia to Europe Pusan, Hong Kong, Singapore, Salalah,

Le Havre, Rotterdam, Felixstowe

4,3 FDA LC4.1 7,2

Europe to Asia Felixstowe, Rotterdam, Le Havre,

Salalah, Singapore, Hong Kong, Pusan

4,3 FDA LC4.2 7,2

Asia to N America EC (via Panama) Shanghai, Qingdao, Pusan, Kobe, (via

Panama), Miami, Norfolk, New York

4,9 FDA LC4.2 7,2

N America EC to Asia (via Panama) New York, Norfolk, Miami,(via Panama),

Kobe, Pusan, Qingdao, Shanghai

4,9 FDA LC4.2 7,2

> 5,000 TEU Container Ship

Transatlantic Westbound Hamburg, Felixstowe, Rotterdam,

Halifax, New York, Norfolk

3,5 FDA LC5.1 5,0

Transatlantic Eastbound Norfolk, New York, Halifax, Rotterdam,

Felixstowe, Hamburg

3,5 FDA LC5.2 5,0

Transpacific Eastbound Kaohsiung, Pusan, Yokohama, Tacoma,

Los Angeles

3,5 FDA LC5.2 15,0

Transpacific Westbound Los Angeles, Tacoma, Yokohama,

Pusan, Kaohsiung

3,5 FDALC5.1 15,0



24 Lloyd's Register

Asia to Europe Pusan, Hong Kong, Singapore, Salalah,

Le Havre, Rotterdam, Felixstowe

4,4 FDA LC5.1 18,0

Europe to Asia Felixstowe, Rotterdam, Le Havre,

Salalah, Singapore, Hong Kong, Pusan

4,4 FDA LC5.2 18,0

Asia-Med-N America (via Suez) Kaohsiung, Hong Kong, Singapore,

Algeciras, Halifax, New York, Norfolk

4,6 FDA LC5.2 8,0

N America-Med-Asia (via Suez) Norfolk, New York, Halifax, Algeciras,

Singapore, Hong Kong, Kaohsiung

4,6 FDA LC5.1 8,0

N America WC-Asia-Europe (via Suez) Seattle, Los Angeles, Pusan, Hong

Kong, Singapore, Le Havre, Felixstowe,

Rotterdam, Hamburg.

6,3 FDA LC5.2 4,0

Europe-Asia-N America WC (via Suez) Hamburg, Rotterdam, Felixstowe, Le

Havre, Singapore, Hong Kong, Pusan,

Los Angeles, Seattle.

6,3 FDA LC5.2 4,0

Note 1. Port time given is per trip.

Table 1.4.14 Fatigue Wave Environment (North Atlantic) trading patterns and loading condition utilisation for ShipRightFDA plus (years, NA) notation

Ship Type/

Group

Trading Route

Loading Condition

% of

service

lifeFrom To

Port

time1

(Days)

Oil TankersN Europe (North Sea, Norway)



N Europe (North Sea, Norway)2,0

Fully loaded

Ballast

50,0

50,0

Bulk Carriers

(Capesize)









4,0

Fully loaded (iron

ore)

Fully loaded (coal)

Heavy ballast

Light ballast

30,5

19,5

30,0

20,0

Bulk Carriers

(Panamax)











4,0

Fully loaded (iron

ore)

Fully loaded (coal)

Fully loaded (grain)

Heavy ballast

Light ballast

10,0

22,5

17,5

30,0

20,0

Bulk Carriers

(Handy size)











4,0

Fully loaded (iron

ore)

Fully loaded (coal)

Fully loaded (grain)

Heavy ballast

Light ballast

8,0

19,5

22,5

25,0

25,0



Lloyd's Register 25

Gas CarriersN Europe (North Sea, Norway)



N Europe (North Sea, Norway)1,5

Fully loaded

Ballast

50,0

50,0

Ore CarriersN America (USA EC, Boston)



N America (USA EC, Boston)4,0

Fully loaded

Ballast

50,0

50,0

Container Ships

(< 500 TEU)









3,5

FDA LC1.1

FDA LC1.1

FDA LC1.2

FDA LC1.2

40,0

40,0

10,0

10,0

Container Ships

(500 - 1,500

TEU)









3,5

FDA LC2.1

FDA LC2.1

FDA LC2.2

FDA LC2.2

45,0

45,0

5,0

5,0

Container Ships

(1,500 - 3,000

TEU)









3,5

FDA LC3.1

FDA LC3.1

FDA LC3.2

FDA LC3.2

15,0

15,0

35,0

35,0

Container Ships

(3,000 - 5,000

TEU)









3,5

FDA LC4.1

FDA LC4.1

FDA LC4.2

FDA LC4.2

15,0

15,0

35,0

35,0

Container Ships

(> 5,000 TEU)









3,5

FDA LC5.1

FDA LC5.1

FDA LC5.2

FDA LC5.2

15,0

15,0

35,0

35,0

Note 1. Port time given is per trip.

4.4 Basis of Fatigue Direct Calculation Procedure

4.4.1 A structural arrangement may contain an array of potential fatigue crack initiation sites. Regions identified as containingthe highest stress fluctuations and/or severe stress concentrations would normally be assessed first.

4.4.2 It is necessary to establish the extent to which fatigue is likely to control the design taking into consideration:

(a) An accurate prediction of the complete service loading patterns throughout the design life.

(b) The elastic response of the structure under these loading patterns.

(c) The detail design, methods of manufacture and degree of quality control which may have a major influence on fatiguestrength, and should be defined more precisely than for statically controlled members. This can have a significant influence ondesign and construction cost.

4.4.3 Traditionally, FDA procedure relies on determining the maximum lifetime stress range, and the expected number ofstress cycles during the life of the structural detail. These two parameters represent the intercept on the axes of the stressspectrum. A suitable distribution function has then to be chosen to represent the lifetime stress spectrum. Finally, the selection of asuitable S-N fatigue strength curve, from a fatigue design code permits calculation of fatigue damage on the assumption of thePalmgren-Miner linear cumulative fatigue damage law.



26 Lloyd's Register

4.4.4 In order to evaluate fatigue lives accurately, it is necessary to establish, as close to reality as possible, the long-termdistribution of the stress range taking into consideration all pertinent stress variations which can be expected during the life of thestructure.

4.4.5 A spectral fatigue assessment procedure is adopted in which the stress ranges and associated number of cycles aredetermined based on a simulation of the ship voyages throughout the entire ship’s life. This simulation makes use of theanticipated ship’s operational profiles, global wave statistical data and mathematical models of the ship.

4.4.6 The specification of design fatigue life should take account of the joints’ accessibility to inspection and proposed degreeof inspection in addition to the consequence of failure.

4.4.7 High cycle fatigue assessment is to be based upon a period of time which is equal to the planned life of the structure.

4.4.8 High cycle related stresses will occur with variable amplitudes of a random nature. The listing of cycles in descendingorder of amplitude results in the development of a stress spectrum. For each calculation it may be necessary to simplify thisspectrum into bands. The stress amplitudes and cycles are to be evaluated from a long-term distribution determined by thestructure's deemed service life.

4.4.9 Fatigue damage assessment must begin by assuming a typical loading sequence and establishment of the number ofcycles expected at each stress level during the structure's service life. For each potential crack location the long-term distributionof relevant stress ranges is to be established and the calculated fatigue life is to be estimated by consideration of cumulativedamage. Although fatigue damage is initially slow, it increases rapidly towards the end of the structural detail’s fatigue life. A linearrelationship between fatigue damage and the number of cycles is often assumed. This is given by Palmgren-Miner's Law.

4.4.10 The cumulative damage factor, D, according to Palmgren-Miner's Law is given as:

D = ∑i = 1

k niN i

where

k = number of stress range components

ni = expected number of stress cycles in the design spectrum which are assumed to occur for the variousstress ranges Si corresponding to Ni

Ni = permissible number of stress cycles for each Si according to the selected S-N curve

To satisfy the acceptance criteria, the value of the accumulative damage factor, D, has to be less than 1,0.

A diagrammatic illustration of the calculation procedures for the FDA Level 2 and 3 assessment is given in Figure 1.4.1 Spectralfatigue analysis procedure (Level 2 and Level 3 assessment).



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Figure 1.4.1 Spectral fatigue analysis procedure (Level 2 and Level 3 assessment)

4.5 Level 1 Assessment: Structural Detail Design Guide

4.5.1 The SDDG is based on the extensive knowledge database compiled from the detail design expertise held by LR’s planapproval and field Surveyors, and it has also been supplemented by analytical, numerical and experimental research work. Thishas allowed the fatigue performance requirement and the practical considerations necessary for the manufacture of structuraldetails to be taken into account.

4.5.2 The primary purpose of the Guide is to promote good detail design at an early stage in the structural design process bygiving consideration to the following aspects:

• Application of fatigue design principles and analysis of fatigue performance.

• Construction tolerances and other practical considerations.

• In-service experience and fatigue performance.

4.5.3 The Guide provides a convenient approach to the design of ship structural details against fatigue by providing guidancefor the following items:

• Identification of critical areas within the ship structure for a given ship type.

• Identification of the stress hot spot locations for each of the critical structural details.

• Provision of a set of alternative improved fatigue life configurations from which an appropriate solution can be selected.

• Recommendations on geometrical configurations, scantlings, welding requirements and construction tolerances.

4.5.4 Where several configurations are offered for a given structural detail, these are graded in terms of their relative fatigue lifeperformance. Methods of improving fatigue life, such as weld toe grinding, weld dressing, etc., are also described.

4.5.5 The development of the Guide is an on-going process with regular updates to reflect the trends in fatigue lifeperformance as obtained from service experience, as well as evolution and feedback from design and construction practices. The



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findings from LR’s ongoing research, including structural detail finite element studies and experimental fatigue testing programme,are also incorporated in the Guide.

4.6 Level 2 Assessment: Integrated Simplified Spectral Fatigue Analysis

4.6.1 The Level 2 Assessment utilises an Integrated Spectral Fatigue Analysis procedure which is a first-principles directcalculation procedure.

4.6.2 The direct calculation computational procedure is described as follows:

(a) The structural detail fatigue strength characteristics, represented by an appropriate S-N curve, are automatically assigned bythe FDA software S-N Curve Expert, using a parametric formulation of the geometrical stress concentration factor derivedfrom a series of systematic finite element analyses of ship structural details carried out by LR.

(b) Wave-induced loads and ship motions are determined from a parametric database consisting of wave-induced load andmotion responses in regular waves, computed using first-principles methods. The procedure allows the determination of theamplitude and the associated phase angle of the global and local loads, and the motions for any ship loading condition, shipspeed, wave frequency, and ship heading.

(c) The structural response is determined from first-principles methods using a combination of beam models and analyticalprocedures. The structural response at each hot spot location is computed in terms of the influence coefficients associatedwith each load component applied to the structural member, and the relevant geometrical stress concentration factor. Theprocedure allows the response of the primary structure to be included in the structural response model.

(d) The short-term total stress response in irregular waves is computed from the structural response influence coefficients, theregular wave load amplitudes and phase angles, and the wave energy spectrum. The stress range is obtained by combiningthe structural response arising from each load component taking into account the relative phase difference between eachstructural load component. Where non-linear and/or non-harmonic behaviour of the load component exists, a time domainsimulation method is applied to obtain the resulting stress range.

(e) For every sea state under consideration, the fatigue damage rate and stress reversal frequency are calculated from the short-term stress response statistics and the fatigue strength characteristics of the structural detail.

(f) A voyage simulation is performed for the given ship type based upon the100A1 Fatigue Wave Environment (Worldwide), orthe North Atlantic Wave Environment. The ship’s motion responses are used in conjunction with sea-keeping criteria in orderto simulate course changing and speed reduction in operation.

(g) The accumulated long-term fatigue damage is computed from each individual sea-state contribution using the probabilitymatrix of sea-state occurrence defined by the computed FDA 100A1 trading pattern, the associated short-term fatiguedamage rate and stress reversal frequency.

(h) In addition to the North Atlantic Wave Environment and the 100A1 Fatigue Wave Environment (Worldwide), Owner definedtrading pattern(s) can also be specified.

(i) The fatigue performance results are provided in a number of ways to assist efficient analysis of the results.

4.7 Level 3 Assessment: First-Principles Spectral Fatigue Analysis

4.7.1 The FDA Level 3 Assessment is a first-principles direct calculation Spectral Fatigue Analysis procedure applicable to anystructural detail.

4.7.2 The concept of the FDA Level 3 Assessment is the same as that of FDA Level 2 Assessment except that:

• the ship’s motions and loads are determined using a first-principles direct calculation procedure of wave-induced loads andmotions; and

• the structural response is determined using a finite element analysis procedure, utilising a global finite element model of theship and local 3-D finite element models of structural details for a large number of discrete wave-induced load cases.

4.7.3 The concepts and analysis methods used in the FDA Level 3 Assessment are given in LR’s ShipRight Fatigue DesignAssessment Level 3 Procedure (Ch 1, 6.1 List of References 6.1.3).



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n Section 5 Tools and Equipment

5.1 General

5.1.1 The FDA Level 3 Guidance and FDA Level 2 software together with the associated software user manual and the SDDGare available for use by both the Shipbuilder and the LR offices.

5.1.2 The ShipRight FDA ICE guidance document is also available for the assessment of fatigue of stiffener end connectionsinduced by ice loading.

n Section 6 References

6.1 List of References

6.1.1 ShipRight FDA – Structural Detail Design Guide.

6.1.2 ShipRight FDA – Software user manual.

6.1.3 ShipRight FDA Level 3 – Guidance on direct calculations.

6.1.4 ShipRight ICE – Fatigue Induced by Ice Loading.

6.1.5 ShipRight Additional Design Procedures – Guidance Notes on the Assessment of Global Design Loads of LargeContainer Ships and other Ships Prone to Whipping and Springing.



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