1、 Guide for Enhanced Shaft Alignment GUIDE FOR ENHANCED SHAFT ALIGNMENT OCTOBER 2015 American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862 Copyright 2015 American Bureau of Shipping ABS Plaza 16855 Northchase Drive Houston, TX 77060 USA Foreword Foreword The ABS
2、 Guide for Enhanced Shaft Alignment has been developed to address requests from owners and operators who wish to perform a more detailed shaft alignment analysis and installation assessment. Vessels designed, constructed and operated in compliance with the requirements of this Guide may be assigned
3、the Class Notation ESA. Assignment of the ESA Notation requires the review of plans and calculations by an ABS Engineering Office and the attendance of an ABS Surveyor during additional shafting alignment efforts. The intention of the Guide is to address shafting arrangements that may benefit from a
4、 more detailed analysis and a more accurate and structured procedure so as to optimize the shaft alignment and improve the service life of the vessels powertrain. This Guide is intended to apply mainly to shaft alignment-sensitive vessels, as defined in this Guide, although it could apply to a wider
5、 range of powertrains including geared installations. The main aspects that distinguish compliance with this Notation from the standard Rule application are: Alignment process is to be conducted after engine or gearbox and other heavy machinery are installed on board and all major steel works are co
6、mpleted at the aft part of the vessel. Shaft alignment optimization calculations are required. Compulsory inclusion of hull deflections to be taken into account in the analysis. Requirement for Lateral Vibration (Whirling) analysis of the powertrain shafting system. Shaft alignment verification at m
7、ore than one service condition. The vessel must be assigned the Tailshaft Condition MonitoringTCM Notation. The ABS Guide for Enhanced Shaft Alignment is to be used in conjunction with all other applicable Rules, Guides and Guidelines published by ABS. This Guide becomes effective on the first day o
8、f the month of publication. Users are advised to check periodically on the ABS website www.eagle.org to verify that this version of this Guide is the most current. We welcome your feedback. Comments or suggestions can be sent electronically by email to rsdeagle.org. ii ABSGUIDE FOR ENHANCED SHAFT AL
9、IGNMENT .2015 Table of Contents GUIDE FOR ENHANCED SHAFT ALIGNMENT CONTENTS SECTION 1 General 1 1 Introduction . 1 1.1 ESA Notation . 1 1.3 Definitions 2 3 Application 3 3.1 General 3 5 Documentation 4 5.1 Documentation to be Submitted 4 TABLE 1 Propulsion Types and Shaft Alignment Systems that can
10、be Covered by the ESA Notation . 4 FIGURE 1 Typical Differences between Some ESA Notation Requirements and ABS Rules 1 SECTION 2 Calculation Requirements for the ESA Notation . 6 1 Calculations 6 1.1 General 6 1.3 Additional Specialized Calculations . 6 3 Hull Girder Deflections 10 3.1 General 10 FI
11、GURE 1 Schematic Showing the Requirement of the Gearbox Forces Calculation in the Shaft Alignment Analysis Report 7 FIGURE 2 Stern Tube Bearing Contact Analysis Screenshot from the ABS Shaft Alignment Software . 8 FIGURE 3 Representation of Critical Speeds for a Whirling Calculation using a Campbell
12、 Diagram 9 FIGURE 4 Screenshot from the ABS Shaft Alignment Software Showing Typical Data Required for Fast Determination of Hull Deflection for Shaft Alignment Optimization Analysis . 10 FIGURE 5 Typical Finite Element Model for the Purposes of Hull Deflection Calculations . 11 ABSGUIDE FOR ENHANCE
13、D SHAFT ALIGNMENT .2015 iii SECTION 3 Alignment Procedure . 12 1 General Requirements 12 1.1 Major Stages . 12 3 Ship in Drydock or Very Light Ballast (“Nearly Lightship“) Condition . 12 3.1 Conditions 12 3.3 Means of Bearing Reaction Measurement and Verification . 12 3.5 Drydock or Very Light Balla
14、st Condition (at Quay). 14 3.7 Light Ballast and Full Ballast Conditions during Sea Trials 15 3.9 Fully Laden Condition during Sea Trials 15 3.11 Shaft Installation Procedure for Direct Drive Powertrain without a Forward Sterntube Bearing . 15 3.13 Shaft Installation Procedure for Geared Drive Power
15、train . 16 3.15 Recordings 16 TABLE 1 Performance Characteristics of Typical Measurement Techniques 13 FIGURE 1 Bearing Reaction Values During Sea Trials for Different Vessel Conditions for the Forward Sterntube Bearing (FWD), the Intermediate Bearing (IB) and the Aftmost Main Engine Bearing (ME) 17
16、 FIGURE 2 Correlation between Measured and Calculated Bearing Reaction Values for a Specific Vessel Condition 17 SECTION 4 Sea Trials 18 1 General Requirements 18 1.1. Test Procedure 18 1.3 Running-in Procedure 19 FIGURE 1 Bearing Temperatures Monitored during Acceptance Sea Trials . 18 SECTION 5 Ma
17、intenance of ESA Notation . 20 1 Maintenance of ESA Notation. 20 SECTION 6 Surveys . 21 1 Initial Survey 21 3 Surveys after Construction 21 APPENDIX 1 Definitions of Shaft Alignment Optimization . 22 1 Shaft Alignment Optimization Alternative Definitions . 22 FIGURE 1 2D Design Optimization Mathemat
18、ical Concept . 22 FIGURE 2 3D and higher Design Optimization Mathematical Concept . 23 APPENDIX 2 References 24 iv ABSGUIDE FOR ENHANCED SHAFT ALIGNMENT .2015 Section 1: General SECTION 1 General 1 Introduction 1.1 ESA Notation Requirements of this Guide are optional for classification purposes. How
19、ever, where assignment of the optional notation ESA Enhanced Shaft Alignment is being requested, provisions of this Guide are compulsory. This Guide provides criteria for additional calculation requirements, such as design optimization, as well as more detailed requirements regarding the shaft align
20、ment procedures in support of the optional notation ESA - Enhanced Shaft Alignment. Typical differences can be explained through the flowchart examples of Section 1, Figure 1. FIGURE 1 Typical Differences between Some ESA Notation Requirements and ABS Rules ABS Steel Vessel Rules4-3-2/11.1.2(e)Shaft
21、 Alignment CalculationsHull Deflections Available: Bearing Reaction verification measurements taken in one condition (such as Dry Dock or Very Light Ballast condition).Hull Deflections Not Available: Load measurements taken in multiple loading conditions, as agreed.Whirling Calculations Requirements
22、 No forward ST bearing Bearing Span 450d Supports outside of hull Cardan shafts incorporated Calculated with all bearings loadedTCM Notation OptionalShaft Installation Procedure for Direct Drive Powertrain without a Forward Sterntube Bearing References in 4-3-2/7.3.4, 4-3-2/11.1.2(c)ESA NotationShaf
23、t Alignment CalculationsHull Deflections Compulsory Load measurements taken under ballast and fully laden conditions, as per 2/1.1.1(a) and 2/1.1.1(b) of the ESA Guide.Whirling Calculations Requirements Unanimously (i.e., all cases under ESA Notation) Calculated with all bearings loaded Calculated w
24、ith fore ST bearing unloadedTCM Notation CompulsoryShaft Installation Procedure for Direct Drive Powertrain without a Forward Sterntube Bearing 7 Steps distinguishing this procedure from the procedure followed when a forward sterntube bearing is included in the shaftline, Subsection 3/11 of the ESA
25、Guide.ABSGUIDE FOR ENHANCED SHAFT ALIGNMENT .2015 1 Section 1 General 1.1.1 Objective The objective of this Guide is to identify additional requirements and procedures beyond the minimum requirements currently specified in the ABS Rules for Building and Classing Steel Vessels so as to further enhanc
26、e the shaft alignment. Vessels designed, constructed and operated in compliance with the requirements of this Guide may be assigned the Class Notation ESA. 1.1.2 General Requirements The shaft alignment procedure and measurements are to commence after the vessel stern blocks are fully welded and all
27、 of the heavy stern structure is in place, such as any stern accommodation block, including the main engine and/or gearbox. This is to be verified by the attending Surveyor. 1.3 Definitions 1.3.1 ABS Rules The ABS Rules for Building and Classing Steel Vessels is hereafter referred to as “Steel Vesse
28、l Rules”. 1.3.2 ESA Notation The notation granted based upon compliance with the requirements described in this Guide. 1.3.3 FEA Finite Element Analysis. 1.3.4 MCR Maximum Continuous Rating. 1.3.5 Very Light Ballast Condition The condition in which the vessel is either in dry-dock or afloat at a qua
29、y with minimum ballast nearing a “lightship” condition. This condition is expected to have the least influence in the calculations with hull deflections that would affect the shaft alignment and therefore, it is considered as a condition without hull deflections. 1.3.6 Global Reference Line In the s
30、haft alignment sighting, the global reference line is the 0 (zero) datum used as the reference for all bearing offsets. All bearing offsets values are recorded based on this datum. 1.3.7 Shaft Alignment The configuration of the shafts and bearings relative to the centerlines of the bearings from the
31、 theoretical straight line condition, so as to achieve an acceptable bearing load distribution. 1.3.8 Alignment Optimization Alignment optimization is a condition where a mathematically predicted set of bearing offsets produces a satisfactory bearing load distribution for more than one alignment con
32、dition. The shaft alignment optimization estimates the most possible uniform bearing load distribution for any given vessel loading case., It will produce an optimum set of bearing offsets, which will satisfy the vessel loading conditions from very light ballast to the fully-laden condition. Knowing
33、 the hull deflections envelope together with the required operating conditions (e.g. fully loaded, hot dynamic), a bearing offsets range can be defined within which acceptable bearing load distribution. Performing a reverse engineering calculation with the desired bearing load distribution as input
34、and the bearing offsets range also as input, a specific set of bearing offsets can be calculated (usually more than one) as output, which is to be acceptable under all loading conditions. This set of bearing offsets is said to be optimal and the shaftline is said to be optimum for alignment purposes
35、, in accordance to the definition given to the alignment optimization. 2 ABSGUIDE FOR ENHANCED SHAFT ALIGNMENT .2015 Section 1 General 1.3.9 M/E Main Engine. 1.3.10 TCM ABS Tailshaft Condition Monitoring Notation. 1.3.11 Shaft Alignment Sensitive Vessels Large tank vessels such as Suezmax, VLCC, ULC
36、C, LNGC, large bulk carriers, such as Capesize and VLOC, and large container vessels, i.e. above 9000 TEU are considered to be shaft alignment sensitive vessels. In addition, the following propulsion systems are considered to be potentially shaft alignment-sensitive installations: Directly driven pr
37、opeller installations Low speed diesel installations Systems with relatively short and rigid shafting Vessels with a relatively flexible hull structure Vessels with twin screw installations 3 Application 3.1 General 3.1.1 Notation Assignment Vessels designed and constructed in compliance with the op
38、tional requirements of this Guide may be assigned the Class Notation ESA. While the notation has been developed primarily for shaft alignment sensitive vessels and propulsion systems, other types of vessels and other types of powertrains may be granted the ESA Notation. 3.1.2 Bearings The ESA Notati
39、on is available only for vessels fitted with oil lubricated types of bearings. 3.1.3 Survey The Surveyor is to attend all stages of alignment as described herein. The shipyard is to produce a log with the recordings of all the shaft alignment installation steps, including the sighting data recorded
40、along with the manufacturers acceptance criteria. The same is to be submitted to the ABS Engineering Office for review and for future reference. 3.1.4 Correlation with Calculations The onboard shaft alignment is to be consistent with the system description and input parameters as listed in the appro
41、ved calculations. Correlation between measurements and calculations for various shaft alignment conditions is to be verified at all times and stages of the process. The correlations criteria between calculations and measurements are defined in 3/3.5xxiv). 3.1.5 Other Powertrains The Class Notation E
42、SA is not applicable to ships designed with azimuthal thrusters or nonconventional shaft lines intended for main propulsion, or as otherwise deemed inappropriate by ABS. ABSGUIDE FOR ENHANCED SHAFT ALIGNMENT .2015 3 Section 1 General 3.1.6 Applicability Requirements Class Notation ESA may be assigne
43、d to ships designed with one or more propulsion shaft lines that comply with the following: i) Propulsion types of direct drives and geared drive installations, as shown in Section 1, Table 1 ii) The additional calculation requirements of Subsection 2/1 including hull deflections and shaft alignment
44、 optimization iii) The shaft alignment processes described in Section 3 of this Guide. iv) Possess the TCM Notation as per 4-3-2/13 of the Steel Vessel Rules 3.1.7 Geared Installations For geared installations, as the low speed shaft will be stiffer than the high speed shaft, only the propeller to g
45、earbox shaft alignment is required to be submitted to ABS for approval. 3.1.8 Alternative Shafting Arrangements Shafting arrangements applicable for the ESA Notation are shown in Section 1, Table 1 below. In cases of specific shafting arrangements not covered by this Guide, ABS may require additiona
46、l calculations to verify compliance with the ESA Notation requirements. TABLE 1 Propulsion Types and Shaft Alignment Systems that can be Covered by the ESA Notation Propulsion Type Prime Mover Alignment System Direct drive installation Low-speed diesel/gas engine from propeller to crankshaft Electri
47、c motor from propeller to rotor shaft Geared drive installation Medium-speed diesel/gas engine from propeller to main gearbox output shaft Steam/gas turbine Electric motor 5 Documentation 5.1 Documentation to be Submitted 5.1.1 Drawings i) Shafting arrangement ii) Intermediate shaft, propeller shaft
48、 drawings iii) Couplings integral, demountable, keyed, or shrink-fit, coupling bolts and keys drawings iv) Shaft bearing drawings v) Shaft seals drawings vi) Propeller drawings vii) Gearbox drawings, as applicable, as necessary viii) Stern tube bearing and intermediate bearing drawings 4 ABSGUIDE FO
49、R ENHANCED SHAFT ALIGNMENT .2015 Section 1 General 5.1.2 Data i) Rated power of main engine and shaft rpm ii) Allowable bearing loads iii) Actual Propeller mass and inertia iv) Hull deflections data for light ballast, ballast and fully laden condition. v) Crankshaft Deflection allowable limits vi) All Bearing Stiffness values and information 5.1.3 Calculations i) Details of shaft alignment calculation as required by the 4-3-2/7.3.2 of the Steel Vessel Rules ii) Details of shaft alignment optimization calculation iii) Aft Stern Tube Bearing Cont
