ShipRight Design and Construction. Fatigue Design Assessment - Application and Notations

Transcription

1 ShipRight Design and Construction June 2015

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3 Contents CONTENTS FATIGUE DESIGN ASSESSMENT - APPLICATION AND NOTATIONS Section 1 General 1 Section 2 Application 4 Section 3 Responsibilities 5 Section 4 Fatigue Design Assessment (FDA) 5 Section 5 Tools and Equipment 24 Section 6 References 25 LLOYD S REGISTER

4 CONTENTS Section 1 General Introduction Application Notations 2 Section 2 Application Identification of critical areas Carrying out the fatigue life assessment 4 Section 3 Responsibilities The Shipbuilder Lloyd s Register 5 Section 4 Fatigue Design Assessment (FDA) FDA Procedure Structural Details requiring FDA Fatigue Wave Environment Basis of Fatigue Direct Calculation Procedure Level 1 Assessment: Structural Detail Design Guide Level 2 Assessment: Integrated Simplified Spectral 24 Fatigue Analysis 4.7 Level 3 Assessment: First-Principles Spectral 24 Fatigue Analysis Section 5 Tools and Equipment 24 Section 6 References 25 2 LLOYD S REGISTER

5 SECTION 1 Fatigue Design Assessment Section 1: General Section 2: Application Section 3: Responsibilities Section 4: Fatigue Design Assessment (FDA) Section 5: Tools and Equipment Section 6: References Section 1: General 1.1 Introduction Successful performance of a ship's hull structure during its service life is of paramount importance. Sophisticated structural analysis techniques permit the designer to confirm that appropriate stress and other acceptance criteria are met and facilitate the optimisation of hull steelweight distribution. Such structural optimisation and the more extensive introduction of higher tensile steels mean that greater emphasis must 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. Fatigue damage can of course lead to failure of the structural element concerned and, in a worst case situation, result in major 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. Experience of ships in service and the application of finite element analysis techniques enable the early identification of high stress locations and structural joints most at risk. Lloyd s Register (hereinafter referred to as LR) recognised that the conventional procedures for determining fatigue life contain a number of drawbacks and a need was seen for an explicit Fatigue Design Assessment (FDA) procedure to be developed. 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 of hull structural detail, LR has developed and introduced a multi-level Fatigue Design Assessment (FDA) procedure. To assist Shipbuilders in the application of the FDA procedure, LR has developed the Structural Detail Design Guide (SDDG) (Reference 1) and direct calculation procedures which incorporate a unique integrated design approach based on the spectral method of analysis. The direct calculation procedures are supported by the ShipRight PC-based software, see Software user manual (Reference 2) and FDA Level 3 Guidance on direct calculations (Reference 3). Guidance for the assessment of fatigue strength of hull structures against ice loads in way of the ice belt regions for ships navigating in ice is given in Reference 4. LLOYD S REGISTER 1

6 SECTION 1 The objective of the FDA procedure, which is applied in addition to normal plan approval, is to obtain an additional confidence level in fatigue performance in the configuration and details of the structure. 1.2 Application The requirements for the ShipRight FDA notation are to be applied on a mandatory basis to new oil tanker and bulk carrier 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. When not mandatory, the ShipRight FDA procedure can be applied on a voluntary basis in order to enhance the level of confidence in the fatigue performance of the hull structure. The ShipRight FDA ICE notation is applied on a voluntary basis. The ShipRight Structural Design Assessment (SDA) 1 and Construction Monitoring (CM) procedures are applied in conjunction with the FDA procedure to ensure that all critical highly stressed areas are identified and appropriate construction tolerances at critical joints are not exceeded during construction. For assignment of the ShipRight FDA and ShipRight FDA plus notations for ships not approved in accordance with the CSR, the scantling requirements in the Rules and Regulations for the Classification of Ships (hereinafter referred to as the Rules for Ships) are to be complied with in addition to the applicable requirements indicated in Table 1.1. For tankers and bulk carriers compliant with CSR, the requirements of the ShipRight FDA plus notation may be applied on a voluntary basis. In this case, the CSR minimum scantlings are to be met in addition to the applicable requirements indicated in Table 1.1 for assignment of the ShipRight FDA plus notation. 1.3 Notations The ShipRight FDA notation may be assigned when an appraisal of the fatigue performance of the hull structure has been made in accordance with this procedure and found to comply with the requirement of 20 years fatigue life based on the 100A1 Fatigue Wave Environment (Worldwide) trading pattern. The ShipRight FDA notation is not applicable to ships approved using the CSR. The ShipRight FDA plus notation may be assigned, upon request, when an additional appraisal of the fatigue performance of selected critical structural arrangements has been made in accordance with this procedure and found to comply with a higher level of fatigue performance than the ShipRight FDA or the CSR for ships approved using these Rules (see Table 1.1 for criteria). The notation is to be followed by the number of years that the vessel has been assessed for and the specific trading pattern, either the worldwide or North Atlantic, denoted by the letters WW and NA respectively, e.g. ShipRight FDA plus (25, WW) and ShipRight FDA plus (25, NA). NA denotes North Atlantic and WW denotes the 100A1 Fatigue Wave Environment (Worldwide) trading pattern for the relevant ship type. These routes are described in Section 4. Where the FDA procedure is applied on a mandatory basis, ships complying with the requirements of this procedure will be assigned the notation ShipRight FDA. 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 or ShipRight FDA plus. The ShipRight FDA ICE notation may be assigned, upon request, as a supplement to the ShipRight FDA or ShipRight FDA plus notation, when an additional appraisal of the fatigue performance of the stiffener end connections against ice loads in the ice belt regions has been made and found to comply with the requirement of the ShipRight Procedure (Reference 4). The notations will be placed in Column 4 against the ship entry in LR s Register of Ships, see Pt 1, Ch 2,2 of the Rules for Ships. A summary of the requirements for ShipRight FDA and ShipRight FDA plus notations for new ships is outlined in Table 1.1. The requirements for ShipRight FDA ICE notation are given in Reference 4. 1 Where FDA plus notation is specified to the application of the CSR, the SDA analysis is not required. 2 LLOYD S REGISTER

7 SECTION 1 Table 1.1 Summary of Requirements for ShipRight FDA and ShipRight FDA plus Notations (New Construction) (see continuation) 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: Assessment of a higher fatigue performance, in association with the criteria in (1) and (2) below, requires: Assessment of a higher fatigue performance, in association with the criteria in (1) and (2) 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. (a) Application of FDA Level 2 to all longitudinal end connections at deck, inner and outer shell and 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 4.2. (a) Application of FDA Level 2 to all longitudinal end connections at deck, inner and outer shell and 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 4.2. 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 4.3.2, 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, (2) Owner specified specific trading pattern(s) additional assessment, see Note 1. (2) Owner specified specific trading pattern(s) additional assessment, see Note 1. NOTES: 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). 2. For ShipRight FDA plus (years, NA) notation, the fatigue assessment is to be based on the assumptions given in LLOYD S REGISTER 3

8 SECTIONS 1 TO 2 Table 1.1 Summary of Requirements for ShipRight FDA and ShipRight FDA plus Notations (New Construction) (conclusion) Feature FDA FDA plus (years, WW) FDA plus (years, NA) 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. ShipRight FDA ShipRight FDA Structural Detail Design Guide ShipRight FDA Level 2 Software User Manual ShipRight FDA Level 3 Guidance on direct calculations. Assessment Procedural Document 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. Pre-contract Consultation NOTES: 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. 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. 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. Section 2: Application 2.1 Identification of critical areas Prior to commencing the application of the FDA procedure, it is necessary to identify those areas and items of structural detail at risk of fatigue damage. Experience with ships in service has enabled LR to provide information to assist the Shipbuilder in determining specific critical locations within these areas which may be vulnerable to fatigue. Particular emphasis is placed on locations where high stress magnitudes may be anticipated and for which correct alignment is important. This information is presented in the SDDG (Reference 1). The Shipbuilder shall utilise this information in conjunction with the results obtained from the application of the ShipRight SDA procedure to identify those critical areas which warrant close attention when carrying out a fatigue life assessment. The minimum critical locations to be considered for the assignment of ShipRight FDA and ShipRight FDA plus notations for each ship type are given in Carrying out the fatigue life assessment In applying the FDA procedure, LR requires the Shipbuilder to consider possible levels of assessment as described in Section 4 of this document. In applying the FDA procedure, the Shipbuilder is required to specify and submit details of the intended fabrication treatments, construction tolerances and defect correction procedures which are required to be utilised in the fatigue life calculation. It is therefore necessary to ensure that these specified treatments, tolerances and correction procedures are complied with during the actual ship construction for the identified critical joints. This is carried out through the application of the CM procedure (see Section 1 of this document for further details). Further guidance on fabrication treatments, construction tolerances and defect correction procedures is given in Chapters 2 and 3 of the SDDG (Reference 1). As indicated previously, LR has developed PC-based software to assist the Shipbuilder in carrying out the FDA Level 2 assessment. A theoretical description of this procedure is given in LR s FDA Level 2 Software user manual, see Reference 2. The FDA Level 2 software is available to designers and the software considers the end connections of the hull girder longitudinal stiffeners. 4 LLOYD S REGISTER

9 SECTIONS 3 TO 4 Section 3: Responsibilites 3.1 The Shipbuilder The Shipbuilder is required to carry out the FDA calculations in accordance with the ShipRight FDA procedure. The Shipbuilder, in conjunction with LR, shall consult with and obtain from the Shipowner, the specification for the ship s trading pattern and service life criteria. Requirement for notation should be confirmed, i.e. standard ShipRight FDA notation with 100A1 Fatigue Wave Environment (Worldwide) trading pattern and 20 years service life or ShipRight FDA plus notation with a higher specification (see Table 1.1 for guidance). Where the ShipRight FDA ICE notation is requested, the expected ice conditions for the specified trading routes shall also be provided. 3.2 Lloyd s Register 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 comply with 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 FDA ICE 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 sequences for welding, fabrication and erection, as appropriate. (f) Ensure that the approved construction tolerances and details fabrication treatments are incorporated into the ShipRight CM plan. (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. (a) (b) (c) Level 1. The proposed joint configurations at critical areas are compared with the structural design configurations specified in the Structural Detail Design Guide, which can offer an improved fatigue life performance. Level 2. This is an spectral direct calculation procedure based on simplified structural models which utilises LR's PC-Windows based software. This procedure has been derived from experience in applying the Level 3 fatigue assessment and is intended for the analysis of secondary stiffener connections. Level 3. This is a full spectral direct calculation procedure based on first principles computational methods, such as hydrodynamic load and ship motion analysis, and finite element analysis. It is intended mainly for the analysis of primary structural details. Where a ShipRight FDA notation or one of the ShipRight FDA plus notations is requested, the FDA Level 1 minimum detail design improvement specified in the SDDG is to be complied with for all primary structural connections unless a satisfactory fatigue life has been predicted by an FDA Level 3 analysis. For alternative arrangement of primary structural connections, or for ship types not included in the SDDG, special consideration will be given by LR for the need to apply a FDA Level 3 assessment. The FDA direct calculation procedures are applicable to structural details within the cargo space region and its integration with other regions of the ship, which are subjected to the action of low frequency wave-induced loads. The assessment of 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 springing responses, see Pt 3, Ch 8,14.3 of the Rules for Ships and Reference Structural Details requiring FDA The structural details and locations required to be assessed by FDA Level 2 and FDA Level 3 procedures are described in this Section. Section 4: Fatigue Design Assessment (FDA) 4.1 FDA Procedure In applying the FDA procedure, LR requires the Shipbuilder to consider three possible levels of assessment as follows: Longitudinal End Connections The fatigue performance of all longitudinal end connections at deck, inner and outer shell and longitudinal bulkheads to transverse structure are to be assessed for the assignment of ShipRight FDA and ShipRight FDA plus notations. The fatigue assessment may be based on either FDA Level 2 or FDA Level 3 analyses. LLOYD S REGISTER 5

10 4.2.2 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 FDA notation 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 4.1. (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 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 4.2. (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 K L factor of 0,66 is to be used with material yield stress 390 N/mm 2 or a K L factor of 0,62 is to be used with material yield stress 460 N/mm 2, see Pt 3, Ch 2,1.2.5 of the Rules for Ships. (ii) condition specified in Pt 3, Ch 8, applies, in which case, the fatigue assessment is to include effect of hull girder springing. Otherwise, the FDA procedure is optional. The assignment of the ShipRight FDA notation or any of the ShipRight FDA plus notations requires fatigue assessment of the structural details listed in Table 4.3. (d) LNG carriers For LNG carriers the FDA procedure is optional. For membrane LNG carriers, the assignment of the ShipRight FDA notation or any of the ShipRight FDA plus notations requires fatigue assessment of the structural details listed in Table 4.4. For other types of LNG carriers the structural details to be investigated for the assignment of the ShipRight FDA notation or any of the ShipRight FDA plus notations are to be specially agreed with LR. (e) (f) LPG carriers For LPG carriers the FDA procedure is optional. The structural details required to be assessed for the assignment of ShipRight FDA, FDA plus (years, WW) and ShipRight FDA plus (years, NA) notations for Type A and Type C LPG carriers are given in Table 4.5. Other Ship Types For ship types not specifically mentioned in this document the application of the FDA procedure is optional. The extent of fatigue analysis required to be carried out for the assignment of the ShipRight FDA notation or any of the ShipRight FDA plus notations is to be specially agreed with LR. 6 LLOYD S REGISTER

11 Table 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, (j) 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. The analysis is to consider the connection between: (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. 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). 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. The analysis is to consider the connection between: (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) (f) side stringer plating connection to outer longitudinal bulkhead (inner skin) plating, 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. NOTES: 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. 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. 3. Other structural connections may be required at the discretion of the responsible LR office. 4. ShipRight FDA Notation is not applicable to oil tankers approved in accordance with the CSR. LLOYD S REGISTER 7

12 Table 4.2 Bulk Carrier Structural Details for Fatigue Assessment Bulk Carrier 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, (b) transverse web frame plating and inner bottom 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 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. The analysis is to be carried out: 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). The analysis is to consider the connection between: (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. The analysis is to be carried out: 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. The analysis is to consider the connection between: (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. The analysis is to be carried out at: transverse bulkhead location of ordinary cargo hold, heavy cargo hold (if fitted) and heavy ballast hold (if fitted) in or closet to midships. 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. The analysis is to be carried out at: 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. NOTES: 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. 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. 3. Other structural connections may be required at the discretion of the responsible LR office. 4. ShipRight FDA Notation is not applicable to bulk carriers approved in accordance with the CSR. 8 LLOYD S REGISTER

13 Table 4.3 Container Ship Structural Details for Fatigue Assessment Container Ship Structural Details ID STRUCTURAL DETAIL 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. 9. Location of high stress gradients identified from the SDA analysis. NOTES: 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. 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. 3. Other structural connections may be required at the discretion of the responsible LR office. LLOYD S REGISTER 9

14 Table 4.4 Membrane Tank LNG Carrier Structural Details for Fatigue Assessment Membrane Tank LNG Carrier Structural Details ID STRUCTURAL DETAIL 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 The analysis is to consider the connection between: (a) inner bottom plating and hopper sloping plate, (b) transverse web frame plating and inner bottom plating, (c) transverse web frame plating and hopper sloping plate, (d) transverse web frame plating and longitudinal girder plating, (e) transverse web frame plating and stringer plating, if applicable, (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 The analysis is to consider the connection between: (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 stringer plating, The analysis is to be carried out at mid-length of a midship cargo tank. 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. 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. NOTES: 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. 2. Items 2 to 8 are to be assessed by means of an FDA Level 3 analysis for the assignment of ShipRight FDA or ShipRight FDA plus notation. 3. Other structural connections may be required at the discretion of the responsible LR office. 10 LLOYD S REGISTER

15 Table 4.5 LPG Carrier Structural Details for Fatigue Assessment LPG Carrier Structural Details ID STRUCTURAL DETAIL 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 The analysis is to consider the connection between: a) inner bottom plating and hopper sloping plate, b) transverse web frame plating and inner bottom plating, c) transverse web frame plating and hopper sloping plate, d) transverse web frame plating and longitudinal girder plating, e) transverse web frame plating and stringer plating, if applicable, 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. 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. NOTES: 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. 2. Items 2 to 5 are to be assessed by means of an FDA Level 3 analysis for the assignment of ShipRight FDA or ShipRight FDA plus notation. 3. Other structural connections may be required at the discretion of the responsible LR office. 4.3 Fatigue Wave Environment FDA 100A1 Fatigue Wave Environment (Worldwide) For the assignment of ShipRight FDA and ShipRight FDA plus notations, LR has derrived FDA 100A1 Fatigue Wave Environment (Worldwide) trading pattersn for specific ship types, using worldwide trading statistics. These trading patterns, which are made up of a number of relevant routes, are used in the spectral fatigue direct calculation for the FDA Level 2 and Level 3 assessments. For all trading patterns, default or otherwise, the probability of encountering a particular sea condition and wave heading is obtained from a voyage simulation programme which makes use of global wave statistical data. For ship types not specified in this Section, the FDA Fatigue Wave Environment will be specially considered by LR Oil Tankers A fully loaded condition and a ballast condition are considered. For each trading route, it is assumed that a ship firstly sails from the 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 4.6 for crude oil tankers and Table 4.7 for product oil tankers. In general, the service speed to be used for FDA calculation is taken as 90 per cent of the maximum service speed as defined in the Rules for Ships, Part 3. For ships designed with large sea-margins, the percentage of maximum service speed to be used for FDA calculations will be specially considered. Ship designers/shipbuilders are required to provide details (e.g. trim and stability calculations) of the required loading conditions for performing the FDA calculation. In general, loading conditions best representing the intended trading operation should be used. Departure conditions (i.e. all fuel tanks are full and full bunkers) are to be considered. LLOYD S REGISTER 11

16 Table A1 Fatigue Wave Environment (Worldwide) trading patterns for crude oil tankers Trading Route Ship Type/Group Exporting Area Importing Area % of service life Very large crude W Asia (Persian Gulf, Ras Tanura) E Asia (Taiwan) 17.0 oil tanker W Asia (Persian Gulf, Ras Tanura) E Asia (Japan, Yokohama) 30.0 (VLCC) W Asia (Persian Gulf, Ras Tanura) N America (Gulf of Mexico, New Orleans) ,000 dwt W Asia (Persian Gulf, Ras Tanura) W Europe (Rotterdam) 21.0 and above N Europe (North Sea, UK/Norway) N America (USA EC, New York) 4.0 Suezmax crude E Europe (Black Sea) W Europe (Med, Marseille) 8.2 oil tanker S America (Venezuela) W Europe (Med, Marseille) ,000- N Europe (North Sea, UK/Norway) N America (USA EC, New York) ,000 dwt N Europe (North Sea, UK/Norway) W Europe (Rotterdam) 16.3 W Asia (Persian Gulf, Ras Tanura) N America (USA WC, Los Angeles) via Pacific Ocean 4.3 W Asia (Persian Gulf, Ras Tanura) W Europe (Med, Marseille) via Cape 9.1 W Asia (Persian Gulf, Ras Tanura) Australasia (Adelaide) 6.6 N America (Alaska) N America (USA WC, Los Angeles) 5.8 W Africa (Nigeria, Bonny) N America (Gulf of Mexico, New Orleans) 24.8 W Africa (Nigeria, Bonny) W Europe (Med, Marseille) 6.8 W Africa (Nigeria, Bonny) W Europe (Rotterdam) 4.6 Aframax crude E Europe (Black Sea) W Europe (Med, Marseille) 9.4 oil tanker S America (Venezuela) N America (USA WC, New Orleans) , ,000 S America (Venezuela) W Europe (Rotterdam) 2.2 dwt S America (Venezuela) S America (Brazil, Santos) 6.9 N Africa (Libya) W Europe (Rotterdam) 4.5 N Europe (North Sea, UK/Norway) N America (USA EC, New York) 5.1 N Europe (North Sea, UK/Norway) W Europe (Rotterdam) 24.4 W Asia (Persian Gulf, Ras Tanura) E Asia (Taiwan) 5.4 W Asia (Persian Gulf, Ras Tanura) S Asia (India, Madras) 2.5 W Asia (Persian Gulf, Ras Tanura) Australasia (Adelaide) 2.0 W Asia (Persian Gulf, Ras Tanura) W Europe (Med, Marseille) 7.5 SE Asia (Indonesia, Ardjuna) E Asia (Japan, Yokohama) 2.4 N America (Alaska) N America (USA WC, Los Angeles) 2.8 Panamax crude N Europe (Latvia, Ventspils) W Europe (Rotterdam) 8.8 oil tanker E Europe (Black Sea) W Europe (Med, Marseille) ,000-80,000 S America (Venezuela) N America (Gulf of Mexico, New Orleans) 27.0 dwt S America (Venezuela) S America (Brazil, Santos) 28.3 N Africa (Libya) W Europe (Rotterdam) 8.1 N Europe (North Sea, UK/Norway) N America (USA EC, New York) 3.7 N Europe (North Sea, UK/Norway) W Europe (Rotterdam) 10.5 W Asia (Persian Gulf, Ras Tanura) W Europe (Med, Marseille) 2.1 SE Asia (Indonesia, Ardjuna) E Asia (Japan, Yokohama) 6.2 Handy crude oil N Europe (Latvia, Ventspils) W Europe (Rotterdam) 13.0 tanker E Europe (Black Sea) W Europe (Med, Marseille) 5.0 5,000-50,000 S America (Venezuela) N America (Gulf of Mexico, New Orleans) 24.8 dwt S America (Venezuela) S America (Brazil, Santos) 38.5 N Africa (Libya) W Europe (Rotterdam) 9.4 E Asia (China, Qingdao) E Asia (Japan, Yokohama) 1.9 SE Asia (Indonesia, Ardjuna) E Asia (Japan, Yokohama) LLOYD S REGISTER

17 Table A1 Fatigue Wave Environment (Worldwide) trading patterns for product oil tankers Trading Route Ship Type/Group Exporting Area Importing Area % of service life Aframax oil E Europe (Black Sea) W Europe (Med, Marseille) 2.0 product tanker N Africa (Libya) N America (USA EC, New York) , ,000 N Europe (North Sea, UK/Norway) N America (USA EC, New York) 12.2 dwt W Asia (Persian Gulf, Ras Tanura) E Asia (Taiwan) 7.7 W Asia (Persian Gulf, Ras Tanura) E Asia (Japan, Yokohama) 28.4 W Asia (Persian Gulf, Ras Tanura) SE Asia (Singapore) 16.7 W Asia (Persian Gulf, Ras Tanura) W Europe (Rotterdam) via Suez 5.0 W Asia (Persian Gulf, Ras Tanura) N America (USA EC, New York) via Suez 9.9 W Asia (Persian Gulf, Ras Tanura) W Europe (Med, Marseille) 3.0 W Asia (Persian Gulf, Ras Tanura) S America (Brazil, Santos) via Cape 5.9 Panamax oil E Europe (Black Sea) W Europe (Med, Marseille) 5.1 product tanker N Europe (Latvia, Ventspils) W Europe (Rotterdam) ,000-80,000 S America (Venezuela) N America (USA EC, New York) 6.4 dwt S America (Venezuela) S America (Brazil, Santos) 12.0 N Africa (Libya) N America (USA EC, New York) 3.2 N America (USA EC, Houston) S America (Brazil, Santos) 5.6 N America (USA EC, Houston) N America (USA EC, New York) 14.2 N America (USA EC, Houston) E Asia (Taiwan) 1.6 N Europe (North Sea, UK/Norway) W Europe (Rotterdam) 7.2 N Europe (North Sea, UK/Norway) N America (USA EC, New York) 4.3 N Europe (North Sea, UK/Norway) S Africa (South Africa, Durban) 3.8 W Asia (Persian Gulf, Ras Tanura) SE Asia (Singapore) 2.9 W Asia (Persian Gulf, Ras Tanura) E Asia (Japan, Yokohama) 4.3 W Asia (Persian Gulf, Ras Tanura) S Asia (India, Madras) 4.2 W Asia (Persian Gulf, Ras Tanura) W Europe (Rotterdam) via Suez 1.3 W Asia (Persian Gulf, Ras Tanura) S America (Brazil, Santos) via Cape 1.5 W Asia (Persian Gulf, Ras Tanura) N America (USA EC, New York) via Suez 4.4 SE Asia (Indonesia, Ardjuna) E Asia (Taiwan) 13.6 SE Asia (Indonesia, Ardjuna) E Asia (Japan, Yokohama) 2.3 Handy oil E Europe (Black Sea) W Europe (Med, Marseille) 5.1 product tanker N Europe (Latvia, Ventspils) W Europe (Rotterdam) 2.1 5,000-50,000 S America (Venezuela) N America (USA EC, New York) 6.5 dwt S America (Venezuela) S America (Brazil, Santos) 12.2 S America (Venezuela) W Europe (Rotterdam) 1.6 N Africa (Libya) N America (USA EC, New York) 2.9 N America (USA EC, Houston) S America (Brazil, Santos) 5.7 N America (USA EC, Houston) N America (USA EC, New York) 14.4 N America (USA EC, Houston) E Asia (Taiwan) 1.7 N Europe (North Sea, UK/Norway) W Europe (Rotterdam) 7.3 N Europe (North Sea, UK/Norway) N America (USA EC, New York) 4.1 N Europe (North Sea, UK/Norway) S Africa (South Africa, Durban) 3.9 W Asia (Persian Gulf, Ras Tanura) E Asia (Taiwan) 5.0 W Asia (Persian Gulf, Ras Tanura) S Asia (India, Madras) 4.2 W Asia (Persian Gulf, Ras Tanura) W Europe (Rotterdam) 1.1 W Asia (Persian Gulf, Ras Tanura) S America (Brazil, Santos) via Cape 1.3 W Asia (Persian Gulf, Ras Tanura) N America (USA EC, New York) via Suez 4.0 SE Asia (Indonesia, Ardjuna) E Asia (Taiwan) 14.7 SE Asia (Indonesia, Ardjuna) E Asia (Japan, Yokohama) Bulk Carriers Fully loaded conditions and ballast conditions are considered. For bulk carriers strengthened for carrying heavy cargo in alternate holds an alternate-hold fully loaded condition should be used for iron ore trading routes. In general, the trading pattern assumes that a ship firstly sails from the importing port/area to the exporting port/area in ballast and then returns to the importing port/area fully loaded, with the exception of handy size bulk carriers which operate on a number of round trip routes in which the ship is assumed 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 be 50 per cent in heavy ballast condition and 50 per cent in light ballast condition. For other sizes of bulk carriers the utilisation of 60 per cent heavy ballast and 40 per cent light ballast is assumed. The FDA Fatigue Wave Environment (Worldwide) 100A1 trading patterns for bulk carriers are summarised in Table 4.8. LLOYD S REGISTER 13

18 Table A1 Fatigue Wave Environment (Worldwide) trading patterns for bulk carriers Trading Route Ship Type/Group Cargo Exporting Area Importing Area % of service life Capesize Iron Ore 61% Australasia (W Australia, Dampier) W Europe (Rotterdam) 6.2 bulk carrier Australasia (W Australia, Walcott) E Asia (Japan, Yokohama) ,000 dwt Australasia (W Australia, Walcott) E Asia (China, Shanghai) 7.1 and above N America (Canada, Sept Isles) W Europe (Belgium, Antwerp) 1.8 S Asia (India, Mormugao) E Asia (Japan, Yokohama) 2.4 S America (Brazil, Tubarao) W Europe (Rotterdam) 8.2 S America (Brazil, Tubarao) E Asia (Japan, Yokohama) via Indian Ocean 12.1 S America (Tubarao, Brazil) E Asia (Taiwan) via Indian Ocean 13.1 Coal 39% Australasia (NSW, Newcastle) E Asia (Japan, Yokohama) 9.9 Australasia (NSW, Newcastle) E Asia (Taiwan) 4.3 Australasia (NSW, Port Kembla) W Europe (Rotterdam) 4.8 N America (Canada, Vancouver) E Asia (Japan, Yokohama) 4.0 S Africa (South Africa, Richard s Bay) E Asia (Japan, Yokohama) 1.9 S Africa (South Africa, Richard s Bay) E Asia (Taiwan) 2.9 S Africa (South Africa, Richard s Bay) W Europe (Rotterdam) 4.0 N America (USA EC, Baltimore) E Asia (Taiwan) 2.4 N America (USA EC, Baltimore) W Europe (Rotterdam) 4.8 Panamax Iron Ore 20% Australasia (W Australia, Dampier) W Europe (Rotterdam) 2.0 bulk carrier Australasia (W Australia, Walcott) E Asia (Japan, Yokohama) ,000-80,000 Australasia (W Australia, Walcott) E Asia (China, Shanghai) 2.3 dwt S America (Brazil, Tubarao) W Europe (Rotterdam) 2.7 S America (Brazil, Tubarao) E Asia (Japan, Yokohama) via Indian Ocean 4.4 S America (Brazil, Tubarao) E Asia (Taiwan) via Indian Ocean 4.7 Coal 45% Australasia (NSW, Newcastle) E Asia (Japan, Yokohama) 11.4 Australasia (NSW, Newcastle) E Asia (Taiwan) 5.0 Australasia (NSW, Port Kembla) W Europe (Rotterdam) 5.6 N America (Canada, Vancouver) E Asia (Japan, Yokohama) 4.6 S Africa (South Africa, Richard s Bay) E Asia (Japan, Yokohama) 2.2 S Africa (South Africa, Richard s Bay) E Asia (Taiwan) 3.3 S Africa (South Africa, Richard s Bay) W Europe (Rotterdam) 4.6 N America (USA EC, Baltimore) E Asia (Taiwan) 2.8 N America (USA EC, Baltimore) W Europe (Rotterdam) 5.5 Grain 35% N America (Canada, Vancouver) E Asia (Taiwan) 2.6 S America (Argentina, Rosario) W Europe (Rotterdam) 2.0 N America (USA EC, Charleston) W Europe (Rotterdam) 4.0 N America (USA EC, Charleston) W Africa (Nigeria, Lagos) 1.2 N America (Gulf of Mexico, Florida, Freeport) E Asia (Taiwan) via Panama 16.5 N America (USA WC, San Francisco) E Asia (Japan, Yokohama) 8.7 Handy bulk Iron Ore 16% Australasia (W Australia, Walcott) E Asia (Japan, Yokohama) 4.4 N America (Canada, Sept Isles) N America (Gulf of Mexico, New Orleans) 1.3 S America (Venezuela, Puerto Ordaz) W Europe (Rotterdam) 2.6 S America (Peru, San Nicolas) E Asia (Taiwan) via Indian Ocean 2.0 S America (Brazil, Tubarao) E Asia (Japan, Yokohama) via Indian Ocean 5.7 Coal 39% Australasia (NSW, Newcastle) E Asia (Japan, Yokohama) 10.8 E Asia (China, Qinhuangdao) E Asia (Japan, Yokohama) 3.0 S America (Venezuela, Maracaibo) W Europe (Rotterdam) 4.6 S Africa (South Africa, Richard s Bay) W Europe (Rotterdam) 15.6 N America (USA EC, Baltimore) E Asia (Japan, Yokohama) 5.0 Grain 45% Australasia (NSW, Newcastle) E Asia (Taiwan) 10.9 N America (USA EC, Charleston) W Europe (Rotterdam) 7.8 N America (USA EC, Charleston) S America (Brazil, Santos) 18.8 N America (USA WC, San Francisco) E Asia (Japan, Yokohama) Liquefied Gas Carriers A fully loaded condition and a ballast condition are considered. The trading pattern assumes that a ship firstly sails from the 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 4.9 for LNG carriers and Table 4.10 for LPG carriers. 14 LLOYD S REGISTER