1、 GUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS 2018 NOTICE NO. 1 MARCH 2018 The following Rule Changes were approved by the ABS Rules Committee on 30 January 2018 and become EFFECTIVE AS OF 1 MARCH 2018. (See http:/www.eagle.org for the consolidated version of the Guide for Building and
2、Classing International Naval Ships 2017, with all Notices and Corrigenda incorporated.) Notes - The date in the parentheses means the date that the Rule becomes effective for new construction based on the contract date for construction, unless otherwise noted. (See 1-1-4/3.3 of the ABS Rules for Con
3、ditions of Classification (Part 1).) PART 3 HULL CONSTRUCTION AND EQUIPMENT CHAPTER 3 SUBDIVISION AND STABILITY SECTION 1 GENERAL REQUIREMENTS (Revise Subsection 3-3-1/1, as follows:) 1 General (1 March 2018) All vessels are to demonstrate that they have adequate subdivision and stability for the in
4、tended service. The stability of each vessel is to be evaluated for all loading conditions indicated in 3-3-1/15, verifying compliance with the intact and damage stability criteria in Appendix 3-3-A1 and taking into account the design considerations indicated in 3-3-1/15, and the results are to be s
5、ubmitted for review. When appropriate, such as for vessels that lift heavy weights on or off the vessel stern or other operations that could affect longitudinal stability, the longitudinal intact stability of the loading conditions is also to be investigated. The maximum allowable KG (or minimum req
6、uired GM) curve shall confirm compliance with the intact and damage criteria in Appendix 3-3-A1. This curve (or series of curves) shall cover the full range of operation (Load Line/maximum draft to arrival condition, and the full range of anticipated trims). The supporting calculations for this curv
7、e shall be submitted for review. Compliance with a subdivision and stability standard that may be specified by the Naval Administration (e.g., the Naval Ship Code) is considered an acceptable alternative to meeting the requirements in this Chapter, subject to such standards being determined by ABS a
8、s being not less effective than the Rules. (Paragraphs 3-3-1/1.1 and 3-3-1/1.3 are unchanged.) ABSGUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 1 Notice No. 1 March 2018 (Add new Part 6, Chapter 3, as follows:) PART 6 OPTIONAL NOTATIONS CHAPTER 3 HULL GIRDER ULTIMATE STRENGTH ASSES
9、SMENT (2018) SECTION 1 GENERAL 1 Application This Section establishes the requirement for the optional notation UHS. The requirements are applicable to the hull structure within 0.4L amidships in sea-going conditions. If the structure of the vessel complies with the requirements in this chapter and
10、Sections 3-2-1 to 3-2-11, it will be classed and distinguished in the Record by the notation UHS placed after the appropriate hull classification notation. PART 6 OPTIONAL NOTATIONS CHAPTER 3 HULL GIRDER ULTIMATE STRENGTH ASSESSMENT SECTION 2 CHECKING CRITERIA 1 Vertical Hull Girder Ultimate Limit S
11、tate The vertical hull girder bending moments are to satisfy the following limit state: SMsw+ WMw RUMwhere Msw= still water bending moment, in kN-m (tf-m), in accordance with 3-2-1/3.3 Mw= maximum wave-induced vertical bending moment, in kN-m (tf-m), in accordance with 3-2-1/3.3.3(a) MU= vertical hu
12、ll girder ultimate bending capacity, in kN-m (tf-m), as defined in 6-3-2/3 S= 1.0 partial safety factor for the still water bending moment w= partial safety factor for the vertical wave bending moment taking into account environmental and wave load prediction uncertainties 1.3 for hogging wave bendi
13、ng moment 1.5 for sagging wave bending moment R= 1.10 partial safety factor for the vertical hull girder bending capacity covering material, geometric and strength prediction uncertainties For vessels where the vertical hull girder bending capacity is evaluated with gross scantlings, Ris to be taken
14、 as 1.25. 2 ABSGUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 Notice No. 1 March 2018 3 Hull Girder Ultimate Bending Capacity 3.1 General The ultimate bending moment capacities of a hull girder section in hogging and sagging conditions are defined as the maximum values (positive MUH
15、, negative MUS) on the static nonlinear bending moment-curvature relationship M-. See 6-3-2/Figure 1. The curve represents the progressive change and collapse behavior of the hull girder under vertical bending moments. Hull girder failure is controlled by buckling, ultimate strength and yielding of
16、longitudinal hull girder structural elements. FIGURE 1 Bending Moment Curvature Curve M- (1 March 2018) MUHMUSMSagging ConditionHogging ConditionThe curvature of the critical inter-frame section, is defined as: = m-1where: = relative angle rotation of the two neighboring cross-sections at transverse
17、 frame positions = transverse frame spacing in m, (i.e., span of longitudinals) The calculation of the hull girder ultimate bending capacity is found by identifying the critical failure modes of all hull girder structural elements. Hull girder structural members compressed beyond their buckling limi
18、t have reduced load carrying capacity. All relevant failure modes for individual structural elements are to be considered in order to identify the weakest inter-frame failure mode. Examples of relevant failure modes are plate buckling, torsional stiffener buckling, stiffener web buckling, lateral or
19、 global stiffener buckling, and their interactions, The effects of shear force, torsional loading, horizontal bending moment and lateral pressure are neglected. 3.3 Physical Parameters For the purpose of describing the calculation procedure in a concise manner, the physical parameters and units used
20、 in the calculation procedure are given below. ABSGUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 3 Notice No. 1 March 2018 3.3.1 Hull Girder Load and Cross Section Properties Mi= hull girder bending moment, in kN-m (tf-m) Fi= hull girder longitudinal force, in kN (tf) Iv= hull girde
21、r moment of inertia around the horizontal neutral axis of intact section, in m4SM = hull girder section modulus, in m3SMdk= elastic hull girder section modulus at deck at side, in m3SMkl= elastic hull girder section modulus at bottom, in m3 = curvature of the ship cross section, in m-1zj= distance f
22、rom baseline, in m 3.3.2 Material Properties yd= specified minimum yield stress of the material, in N/cm2(kgf/cm2) E = Youngs modulus for steel, 2.06 107N/cm2(2.1 106kgf/cm2) = Poissons ratio, may be taken as 0.3 for steel = edge function as defined in 6-3-2/3.9.2 = relative strain defined in 6-3-2/
23、3.9.2 3.3.3 Stiffener Sectional Properties The properties of a longitudinal cross section are shown in 6-3-2/Figure 2. As= sectional area of the longitudinal or stiffener, excluding the associated plating, in cm2b1= smaller outstanding dimension of flange with respect to centerline of web, in cm bf=
24、 total width of the flange/face plate, in cm dw= depth of the web, in cm tp= net thickness of the plating, in cm tf= net thickness of the flange/face plate, in cm tw= net thickness of the web, in cm xo= distance between centroid of the stiffener and centerline of the web plate, in cm yo= distance be
25、tween the centroid of the stiffener and the attached plate, in cm 4 ABSGUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 Notice No. 1 March 2018 FIGURE 2 Dimensions and Properties of Stiffeners (1 March 2018) dwyobebfCENTROID OF WEBAND FACE PLATE(NET SECTION)xob2b1tftwtp3.5 Calculation
26、 Procedure The hull girder ultimate bending capacity MU(MUHor MUS) is defined as the peak value of the curve with vertical bending moment M versus the curvature of the ship cross section as shown in 6-3-2/Figure 1. The curve M- is obtained by means of an incremental-iterative approach. The steps inv
27、olved in the procedure are given below. The bending moment Miwhich acts on the hull girder transverse section due to the imposed curvature iis calculated for each step of the incremental procedure. This imposed curvature corresponds to an angle of rotation of the hull girder transverse section about
28、 its effective horizontal neutral axis, which induces an axial strain in each hull structural element. The stress induced in each structural element by the strain is obtained from the stress-strain curve - of the element, which takes into account the behavior of the structural element in the nonline
29、ar elasto-plastic domain. The force in each structural element is obtained from its area times the stress and these forces are summed to derive the total axial force on the transverse section. Note the element area is taken as the total net area of the structural element. This total force may not be
30、 zero as the effective neutral axis may have moved due to the nonlinear response. Hence, it is necessary to adjust the neutral axis position, recalculate the element strains, forces and total sectional force, and iterate until the total force is zero. Once the position of the new neutral axis is kno
31、wn, the correct stress distribution in the structural elements can be obtained. The bending moment Miabout the new neutral axis (due to the imposed curvature i) is then obtained by summing the moment contribution given by the force in each structural element. The main steps of the incremental-iterat
32、ive approach are summarized as follows: ABSGUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 5 Notice No. 1 March 2018 Step 1 Divide the hull girder transverse section into structural elements, (i.e., longitudinal stiffened panels (one stiffener per element), hard corners and transvers
33、ely stiffened panels). See 6-3-2/3.7. Step 2 Derive the stress-strain curves (also known as the load-end shortening curves) for all structural elements. See 6-3-2/3.9. Step 3 Determine the curvature step size : = ( )vydklyddkEISMSM100,max The curvature for the first step 1 is to be taken as . Derive
34、 the neutral axis zNA-ifor the first incremental step (i = 1) with the value of the elastic hull girder section modulus. See 3-2-1/9. Step 4 For each element (index j), calculate the strain ij= i(zj zNA-i) corresponding to i, the corresponding stress j, and hence the force in the element jAj. The st
35、ress jcorresponding to the element strain ijis to be taken as the minimum stress value from all applicable stress-strain curves - for that element. Step 5 Determine the new neutral axis position zNA-iby checking the longitudinal force equilibrium over the whole transverse section. Hence, adjust zNA-
36、iuntil: Fi= 10-3Ajj= 0 Note jis positive for elements under compression and negative for elements under tension. Repeat from Step 4 until equilibrium is satisfied. Equilibrium is satisfied when the change in neutral axis position is less than 0.0001 m. Step 6 Calculate the corresponding moment by su
37、mming the force contributions of all elements as follows: Mi= 10-3( ) iNAjjjzzA Step 7 Increase the curvature by , use the current neutral axis position as the initial value for the next curvature increment and repeat from Step 4 until the peak value Mu occurs on the M- curve. The ultimate capacity
38、is the peak value Mufrom the M- curve. 3.7 Assumptions and Modeling of the Hull Girder Cross-section In applying the procedure described in this Chapter, the following assumptions are to be made: i) The ultimate strength is calculated at a hull girder transverse section between two adjacent transver
39、se webs. ii) The hull girder transverse section remains plane during each curvature increment. iii) The material properties of steel are assumed to be elastic and perfectly plastic. iv) The hull girder transverse section can be divided into a set of elements which act independently of each other. v)
40、 The elements making up the hull girder transverse section are: Longitudinal stiffeners with attached plating, with structural behavior given in 6-3-2/3.9.2 through 6-3-2/3.9.6 Transversely stiffened plate panels, with structural behavior given in 6-3-2/3.9.7 Hard corners, as defined below, with str
41、uctural behavior given in 6-3-2/3.9.1 vi) The following structural areas are to be defined as hard corners: The plating area adjacent to intersecting plates The plating area adjacent to knuckles in the plating with an angle greater than 30 degrees Plating comprising rounded gunwales 6 ABSGUIDE FOR B
42、UILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 Notice No. 1 March 2018 An illustration of hard corner definition for girders on longitudinal bulkheads is given in 6-3-2/Figure 3. vii) The size and modeling of hard corner elements is to be as follows: It is to be assumed that the hard corner ex
43、tends up to s/2 from the plate intersection for longitudinally stiffened plate, where s is the stiffener spacing It is to be assumed that the hard corner extends up to 20tgrsfrom the plate intersection for transversely stiffened plates, where tgrsis the gross plate thickness Note: For transversely s
44、tiffened plate, the effective breadth of plate for the load shortening portion of the stress-strain curve is to be taken as the full plate breadth (i.e., to the intersection of other plates not from the end of the hard corner). The area is to be calculated using the breadth between the intersecting
45、plates. FIGURE 3 Example of Defining Structural Elements (1 March 2018) a) Example showing side shell, inner side and deck Hard cornerelementsLongitudinalstiffener elementsb) Example showing girder on longitudinal bulkhead Hard cornerelementLongitudinalstiffener elementsABSGUIDE FOR BUILDING AND CLA
46、SSING INTERNATIONAL NAVAL SHIPS .2018 7 Notice No. 1 March 2018 3.9 Stress-strain Curves - (or Load-end Shortening Curves) 3.9.1 Hard Corners Hard corners are sturdier elements which are assumed to buckle and fail in an elastic, perfectly plastic manner. The relevant stress strain curve - is to be o
47、btained for lengthened and shortened hard corners according to 6-3-2/3.9.2. 3.9.2 Elasto-Plastic Failure of Structural Elements The equation describing the stress-strain curve - of the elasto-plastic failure of structural elements is to be obtained from the following formula, valid for both lengthen
48、ed and shortened hard corners (6-3-2/Figure 4A) and lengthened stiffeners (6-3-2/Figure 4B): = ydkN/cm2(kgf/cm2) where = edge function = 1 for 1 = relative strain = ydEE= element strain yd= strain corresponding to yield stress in the element = EydNote: The signs of the stresses and strains in this S
49、ection are opposite to those in the rest of the Rules. FIGURE 4A Example of Stress Strain Curves - (1 March 2018) Stress strain curve - for elastic, perfectly plastic failure of a hard corner compression orshorteningtension orlengtheningydyd8 ABSGUIDE FOR BUILDING AND CLASSING INTERNATIONAL NAVAL SHIPS .2018 Notice No. 1 March 2018 FIGURE 4B Example of Stress Strain Curves - (1 March 2018) Typical stress strain curve - for elasto-plasti
