ABS 177 NOTICE 1-2013 GUIDE FOR SLAMMING LOADS AND STRENGTH ASSESSMENT FOR VESSELS.pdf

1、 ABSGUIDE FOR SLAMMING LOADS AND STRENGTH ASSESSMENT FOR VESSELS .2011 1 GUIDE FOR SLAMMING LOADS AND STRENGTH ASSESSMENT FOR VESSELS MARCH 2011 NOTICE NO. 1 July 2013 The following Rule Changes were approved by the ABS Rules Committee on 31 May 2013 and become EFFECTIVE AS OF 1 JULY 2013. (See http

2、:/www.eagle.org for the consolidated version of the Guide for Slamming Loads and Strength Assessment for Vessels, 2011, 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 fo

3、r construction. (See 1-1-4/3.3 of the ABS Rules for Conditions of Classification (Part 1).) SECTION 8 DIRECT STRENGTH ASSESSMENT 3 Shell Plating 3.1 Bowflare Slamming (1 July 2013) (Revise definition of f1, as follows.) f1= 0.90Smfyfor side shell plating in the region forward of 0.125L, from the for

4、ward perpendicular, in N/cm2(kgf/cm2, lbf/in2) = 0.75Smfyfor side shell plating in the region between 0.125L and 0.25L, from the forward perpendicular 5 Shell Longitudinals and Stiffeners (Revise Paragraph 8/5.1, as follows.) 5.1 Bowflare Slamming (1 July 2013) The net section modulus of the shell l

5、ongitudinal (or frame), including the associated effective plating, is not to be less than that obtained from the following equation: SM = M/fbcm3(in3) M = ps s2103/k N-cm (kgf-cm, lbf-in) where k = 16 (16, 111.1) ps= design slamming pressure as described in Subsection 7/3, in N/cm2(kgf/cm2, lbf/in2

6、) s = spacing of longitudinal or transverse frames, in mm (in.) Notice No. 1 July 2013 2 ABSGUIDE FOR SLAMMING LOADS AND STRENGTH ASSESSMENT FOR VESSELS .2011 = unsupported span of the frame, in m (ft) fb= 0.9Smfyfor transverse and longitudinal frames in the region forward of 0.125L from the FP, in

7、N/cm2(kgf/cm2, lbf/in2) = 0.8Smfyfor transverse and longitudinal stiffeners in the region between 0.125L and 0.25L, measured from the FP, in N/cm2(kgf/cm2, lbf/in2) = 0.95Smfyfor stern slamming, in N/cm2(kgf/cm2, lbf/in2) Smand fyare defined in Subsection 8/3. The associated effective breadth of pla

8、ting is to be taken as spacing of longitudinal or transverse frames or 20% of the unsupported span, whichever is less. (Revise Paragraph 8/5.3 and add new Figure 1, as follows.) 5.3 Bottom and Stern Slamming (1 July 2013) In case of bottom or stern slamming, an ultimate strength approach considering

9、 plasticity may be employed to estimate section modulus to the corresponding slamming pressure. The net plastic section modulus, SMpl, of each individual stiffener, is not to be less than: SMpl= yabdgsfCfskp2cm3 (in3) where k = 1000 (1000, 144) ps= slamming pressure as described in Subsection 7/3, i

10、n N/cm2(kgf/cm2, lbf/in2) s = spacing of longitudinal or transverse frames, in mm (in.) = unsupported span of the frame, in m (ft) fbdg= bending moment factor = +218snns= 2.0 for continuous stiffeners or where stiffeners are bracketed at both ends Ca= permissible bending stress coefficient = 0.9 fy=

11、 minimum specified yield point of the material, in N/cm2(kgf/cm2, lbf/in2) The associated effective breadth of plating may be taken as the spacing of longitudinal or transverse frames. The net plastic section modulus can be calculated using the following formulae. When the cross-sectional area of th

12、e attached plate exceeds the cross-sectional area of the stiffener to which the plate flange is attached, the actual net plastic section modulus, Zp, in cm3(cm3, in3) is given by: Zp= Apntpn/(2 c4) + 3422sincthwwnw+ Afn(hfcsin w bwcos w)/c4where Apn= net cross-sectional area of the attached plate, i

13、n cm2(cm2, in2) tpn= net attached plate thickness, in mm (mm, in.) Notice No. 1 July 2013 ABSGUIDE FOR SLAMMING LOADS AND STRENGTH ASSESSMENT FOR VESSELS .2011 3 hw= height of stiffener web, in mm (mm, in.), see Section 8, Figure 1 Afn= net cross-sectional area of stiffener flange, in cm2(cm2, in2)

14、hfc= height of stiffener measured to center of the flange area, mm (mm, in.), see Section 8, Figure 1 bw= distance from mid thickness plane of stiffener web to the center of the flange area, in mm (mm, in.), see Section 8, Figure 1 c4= 10 (10, 1) h = height of stiffener, in mm (mm, in.), see Section

15、 8, Figure 1 twn= net web thickness, in mm (mm, in.) = tw tctw= gross web thickness, in mm (mm, in.), see Section 8, Figure 1 tc= corrosion deduction, in mm (mm, in.), to be subtracted from the web and flange thickness w= smallest angle between attached plate and stiffener web, measured at the midsp

16、an of the stiffener, see Section 8, Figure 1. The angle wmay be taken as 90 degrees provided the smallest angle is not less than 75 degrees. s = spacing of longitudinal or transverse frames, in m (m, in.) When the cross-sectional area of the stiffener exceeds the cross-sectional area of the attached

17、 plate, the plastic neutral axis is located a distance zna, in mm (mm, in.), above the attached plate, given by: zna= (24c Afn+ hwtwn 34c tpns)/(2 twn) and the net plastic section modulus, Zp, in cm3(cm3, in3) is given by: Zp= tpns(zna+ tpn/2)sin w+ +43422/cossin)(2sin)(cbzhActzzhwwwnafcfnwwnnanawFI

18、GURE 1 Stiffener Geometry (1 July 2013) stpbfbwhwtwhhfcw(Renumber subsequent figures in Section 8 accordingly.) Notice No. 1 July 2013 4 ABSGUIDE FOR SLAMMING LOADS AND STRENGTH ASSESSMENT FOR VESSELS .2011 7 Slot Connections (1 July 2013) (Revise Subsection 8/7, as follows.) Each slot connection un

19、der the design slamming pressure is to be verified using the following formulae: fb= P1/As58 for Asin in2= 1.85 for As 2.2 = 1.85 0.2883(As 2.2) for 2.2 9.0 For intersecting of asymmetrical stiffeners = 0.68 + 0.0172 d/Asfor din cmand Asin cm2= 0.68 + 0.00677 d/Asfor din inches and Asin in2If the length of direct and shear connections are different, their mean value is to be used instead of d, and in case of a single lug, the value is c. Smand fyare as defined in Subsection 8/3. For flat bar stiffener with soft-toed brackets, the brackets may be included in the calculation of As.