ABS 172-2017 GUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS.pdf

1、 Guidance Notes on Springing Assessment for Container Carriers and Ore Carriers GUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS JUNE 2017 American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862 2017 American Bureau of Shipping. All

2、rights reserved. ABS Plaza 16855 Northchase Drive Houston, TX 77060 USA Foreword Foreword The 2017 edition of these Guidance Notes expands the scope from just container carriers to include ore carriers; which has necessitated the title change to the ABS Guidance Notes on Springing Assessment for Con

3、tainer Carriers and Ore Carriers. These Guidance Notes provide detailed procedures for the assessment of springing loads and the subsequent structural fatigue damage for container and ore carriers. The technical background is based on direct analysis of hydrodynamic load and structure dynamic respon

4、se. Additionally, these Guidance Notes supplement the Rules and Guides that ABS has issued for the Classification for container carriers. The ABS Guide for Application of Higher-Strength Hull Structural Thick Steel Plates in Container Carriers requires the evaluation of the springing effect on fatig

5、ue damage of hull structures. These Guidance Notes address how to carry out such evaluations. The 2014 edition included an updated wave scatter diagram table and editorial changes. The 2017 edition includes new and updated standard speed profiles, a new time-domain approach for fatigue damage, updat

6、ed S-N curves to include second segment, and editorial changes. These Guidance Notes become effective on the first day of the month of publication. Users are advised to check periodically on the ABS website www.eagle.org to verify that this version of these Guidance Notes is the most current. Commen

7、ts or suggestions can be sent electronically to rsdeagle.org Terms of Use The information presented herein is intended solely to assist the reader in the methodologies and/or techniques discussed. These Guidance Notes do not and cannot replace the analysis and/or advice of a qualified professional.

8、It is the responsibility of the reader to perform their own assessment and obtain professional advice. Information contained herein is considered to be pertinent at the time of publication, but may be invalidated as a result of subsequent legislations, regulations, standards, methods, and/or more up

9、dated information and the reader assumes full responsibility for compliance. This publication may not be copied or redistributed in part or in whole without prior written consent from ABS. ii ABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 Table of Contents GU

10、IDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS CONTENTS SECTION 1 Introduction 1 1 General . 1 2 Springing Phenomenon 1 3 Springing Assessment Procedure 2 FIGURE 1 Time History of Measured Vertical Bending Moment . 1 FIGURE 2 Springing Assessment Procedure. 3 SECTION 2

11、Loading Conditions, Speeds, and Headings . 4 1 General . 4 2 Loading Conditions . 4 3 Standard Speed Profile . 4 4 Wave Heading 4 TABLE 1 Standard Speed Profile for Container Carriers . 4 TABLE 2 Standard Speed Profile for Ore Carriers . 4 SECTION 3 Wave Environments . 5 1 Wave Scatter Diagram 5 2 W

12、ave Spectrum 5 TABLE 1 ABS Wave Scatter Diagram for Unrestricted Service Classification . 5 SECTION 4 Springing Susceptibility Assessment 7 1 General . 7 2 Hull Girder Natural Frequency 7 3 Wave Characteristics 7 4 Springing Susceptibility . 8 FIGURE 1 Probability Distribution of Tz8 FIGURE 2 Typica

13、l Dynamic Amplification Factor . 9 FIGURE 3 Springing Susceptibility Indicator 9 ABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 iii SECTION 5 Calculation of Response Amplitude Operator . 10 1 General . 10 2 Vertical Bending Moment RAOs of Rigid Body . 10 2.1

14、General Modeling Consideration . 11 2.2 Hydrostatic Balance . 11 2.3 Roll Damping . 11 3 Vertical Bending Moment RAO of Flexible Body 12 3.1 Calculation of 2-Node Vibration Mode . 12 3.2 Hydroelasticity . 13 3.3 Large Range of Wave Frequency 13 4 Springing Damping . 14 5 Stress RAO Calculation 14 FI

15、GURE 1 Definition of Ship Motion . 10 FIGURE 2 Vertical Bending Moment RAO (rigid body) 12 FIGURE 3 2-Node Vertical Vibration Mode 12 FIGURE 4 Bending Stiffness Distribution . 13 FIGURE 5 Vertical Bending RAO Distribution 13 SECTION 6 Response Statistics . 15 1 General . 15 2 Short Term Statistics .

16、 15 FIGURE 1 Vertical Bending Moment Response Spectra . 16 SECTION 7 Fatigue Assessment . 17 1 General . 17 2 Frequency-Domain Approach for Fatigue Damage 17 2.1 General 17 2.2 Wave-Frequency Response Fatigue Damage . 18 2.3 Combined Wave and Springing Response Fatigue Damage . 18 3 Time-Domain Appr

17、oach for Fatigue Damage . 19 3.1 General 19 3.2 Short-Term Fatigue Damage . 20 3.3 Long-Term Fatigue Damage 20 4 Fatigue Damage Assessment . 21 4.1 Springing Contribution to Fatigue Damage 21 4.2 Fatigue Damage Assessment 21 APPENDIX 1 Fatigue Strength Assessment . 22 1 General . 22 1.1 Note . 22 1.

18、2 Applicability 22 1.3 Loadings 22 1.4 Effects of Corrosion . 22 1.5 Format of the Criteria . 22 iv ABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 2 Connections to be Considered for the Fatigue Strength Assessment 23 2.1 General 23 2.2 Guidance on Locations f

19、or Container Carriers 23 2.3 Guidance on Locations for Ore Carriers 23 2.4 Fatigue Classification 24 3 Fatigue Damage Calculation 36 3.1 Assumptions 36 3.2 Criteria . 37 3.3 Long Term Stress Distribution Parameter, 37 3.4 Fatigue Damage 37 4 Fatigue Inducing Loads and Load Combination Cases 40 4.1 G

20、eneral 40 4.2 Wave-induced Loads . 40 4.3 Combinations of Load Cases for Fatigue Assessment 40 5 Determination of Wave-induced Stress Range 41 5.1 General 41 5.2 Hatch Corners . 41 6 Hot Spot Stress Approach with Finite Element Analysis 50 6.1 Introduction 50 6.2 Calculation of Hot Spot Stress at a

21、Weld Toe . 51 6.3 Calculation of Hot Spot Stress at the Edge of Cut-out or Bracket 53 TABLE 1 Fatigue Classification for Structural Details 25 TABLE 2 Welded Joint with Two or More Load Carrying Members for Container Carriers . 28 TABLE 3 Welded Joint with Two or More Load Carrying Members for Ore C

22、arriers 34 TABLE 4 Combined Load Cases for Fatigue Strength Formulation for Container Carriers . 40 TABLE 5 Combined Load Cases for Fatigue Strength Formulation for Ore Carriers 41 FIGURE 1 Basic Design S-N Curves . 39 FIGURE 2 Hatch Corners at Decks and Coaming Top 48 FIGURE 3 Circular Shape 49 FIG

23、URE 4 Double Curvature Shape 49 FIGURE 5 Elliptical Shape 49 FIGURE 6 Hatch Corner for Longitudinal Deck Girder . 50 FIGURE 7 . 51 FIGURE 8 . 53 ABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 v This Page Intentionally Left Blank ABSGUIDANCE NOTES ON SPRINGING

24、 ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 1 Section 1: Introduction SECTION 1 Introduction 1 General (1 June 2017) The design and construction of the hull, superstructure, and deckhouses of container carriers and ore carriers are to be based on the applicable requirements of the ABS

25、Rules and Guides. As a supplement to the ABS Rules and Guides, these Guidance Notes provide detailed procedures for assessment of springing and the subsequent structural fatigue damage for container carriers and ore carriers. The procedure is easy to use and can be utilized to make quick estimates o

26、f the fatigue damage due to springing at the conceptual design phase and to perform a sensitivity study of its variation with main dimensions and operational profiles. The technical background is based on the direct analysis of hydrodynamic load and structure dynamic response. 2 Springing Phenomenon

27、 (1 June 2017) Springing is wave-induced hull girder vibration, and it is mainly excited by waves with an encounter frequency coinciding with the springing frequency. For a hull girder vibration, the most important springing frequency is its 2-node vertical natural vibration frequency. Springing can

28、 also be excited by waves with an encounter frequency of half of the springing frequency due to the second order contribution to the response. Springing could increase the fatigue load of the vessel, although its contribution to the extreme hull girder load may not be significant. Springing is not a

29、 new topic. Early springing research has mainly focused on inland water ships. These ships, with large length/depth ratios, are flexible operating at low draft. Springing was not considered important for oceangoing ships due to the general observation that oceangoing vessels were relatively more rig

30、id and their hull girder natural frequencies of vibration are farther away from the encountered wave frequencies. However, wave-induced hull girder vibration has been observed from full-scale measurements in oceangoing ships (see Section 1, Figure 1). Also, with the rapid growth in ship size, especi

31、ally container carriers, the new and next generations of post-Panamax container carriers are relatively flexible. These Guidance Notes provide procedures on the assessment of springing contribution to the structural fatigue damage and focus on the application to container carriers and ore carriers.

32、FIGURE 1 Time History of Measured Vertical Bending Moment Measured VBM Filtered VBM 2-node vibration Section 1 Introduction 3 Springing Assessment Procedure The recommended springing assessment procedure includes the following: i) Determine the critical loading conditions, forward speed, and operati

33、onal headings. ii) Select wave environmental data, such as wave scatter diagram and wave spectrum. iii) Perform springing susceptibility assessment. iv) Perform detailed springing assessment: Calculate vertical bending moment/stress RAOs including only rigid body motions. Calculate vertical bending

34、moment/stress RAOs including rigid body motions and 2-node vibration. Calculate stress response statistics and fatigue damage including only rigid body motions. Calculate stress response statistics and fatigue damage including rigid body motions and 2-node vibration. Calculate total fatigue damage i

35、ncluding only rigid body motions. Calculate total fatigue damage including rigid body motions and 2-node vibration. Calculate springing contribution to fatigue damage. The analysis flowchart is given in Section 1, Figure 2. Detailed descriptions for the analysis procedures are given in Sections 2 th

36、rough 7. 2 ABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 Section 1 Introduction FIGURE 2 Springing Assessment Procedure Assemble OperationalConditionsObtain Wave EnvironmentalConditionsPerform SpringingSusceptibility AssessmentIf not satisfiedPerform Detaile

37、d Springing AnalysisFor each heading, frequency, and speedCalculate BM/stress RAOs including only rigid body motionsCalculate BM/stress RAOs including rigid body motions and 2-node vibration modeFor each sea state (Hs, Tz) and headingCalculate stress response statistics and damage including only rig

38、id body motionsCalculate stress response statistics and damage including rigid body motions and2-node vibration modeFor an operational condition (speed, heading, loading condition) and wave scatter diagramAdd up the damage contributions including only rigid body motionsAdd up the damage contribution

39、s including rigid body and 2-node vibrationCalculate damage contributions due to 2-node vibrationABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 3 Section 2: Loading Conditions, Speeds, and Headings SECTION 2 Loading Conditions, Speeds, and Headings 1 General

40、For a given vessel, springing is influenced by, among other factors, loading conditions, encountered waves, and vessel speed. These conditions need to be considered in the springing assessment. 2 Loading Conditions (1 June 2017) For the fatigue assessment of a vessel, a minimum of two loading condit

41、ions is recommended: Homogeneous loading condition at design draft Homogeneous loading condition at lowest draft 3 Standard Speed Profile (1 June 2017) In high seas, the ship speed may be reduced voluntarily or involuntarily. If a specific operational profile for the vessel is not available, a stand

42、ard speed profile is to be applied based on the significant wave height as shown in Section 2, Table 1 for container carriers and Section 2, Table 2 for ore carriers, where Vdis the design speed. 4 Wave Heading It is assumed that springing mainly occurs in bow sea conditions. It is recommended that

43、wave headings of head sea (180-degree), 165-degree, and 150-degree bow seas are to be included in the springing analysis. TABLE 1 Standard Speed Profile for Container Carriers (1 June 2017) Significant Wave Height, Hs Speed 0 14.5 1 5 13 19 19 13 7 77 Sum over All Heights 8 326 3127 12779 24880 2687

44、4 18442 8949 3335 1014 266 100000 2 Wave Spectrum Sea wave conditions are to be modeled by the two-parameter Bretschneider spectrum, which is determined by the significant wave height and the zero-crossing wave period of a sea state. The wave spectrum is given by: S() = 4524)/(25.1exp165pspH Section

45、 3 Wave Environments where S= wave energy density, m2-sec (ft2-sec) Hs= significant wave height, m (ft) = angular frequency of wave component, rad/sec p= peak frequency, rad/sec = 2/TpTp= peak period, sec = 1.408 TzTo consider short-crested waves, “cosine squared” spreading is to be utilized, which

46、is defined as: f() = k cos2( 0) where = wave heading, following sea is 0 degrees, and head sea is 180 degrees, in the range of 0 2 0+ 20= main wave heading of a short-crested wave k = factor determined such that the summation of f() is equal to 1.0, i.e.: = +=2/02/01)(f 6 ABSGUIDANCE NOTES ON SPRING

47、ING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 ABSGUIDANCE NOTES ON SPRINGING ASSESSMENT FOR CONTAINER CARRIERS AND ORE CARRIERS .2017 7 Section 4: Springing Susceptibility Assessment SECTION 4 Springing Susceptibility Assessment 1 General Springing is wave-induced vibration. Its effec

48、t on the operation and the structure of vessels can become important when the natural frequency of the vessel is close to the encountered wave frequency. If the natural frequency of the vessel is far from that of encountered waves, springing effect may be considered as insignificant. The first step

49、in the springing assessment is to evaluate the springing susceptibility of the vessel. This Section describes the recommended springing susceptibility criteria. 2 Hull Girder Natural Frequency (1 February 2014) The hull girder natural frequency can be obtained through finite element method, beam method, or full-scale measurement. If they are not available, the following formula can be used to estimate hull girder natural frequency: n= Iv/(i3BPL )1/2, rad/sec where: = 321500 (176118) Iv= moment of inertia, m4(ft4) i= vi