外文原文Structural Reliability Analysis of a Single Hull Bulk Carrier and a Double Hull Bulk CarrierProfessional paper[Abstract]：The ultimate bending moment and the maximal shear stress of two structural forms (sin -gle-hu11 and double—hul1) are calculated by using the combined moment which determined by stochastic process, and then the assessment of reliability is carried out．The results indicate that by introducing the double hull structure，the shear stress decreases a lot，while the capability resistance to bending can be enhanced to some extent also．Finally，the effects on ultimate bending moment and the maximum shear stress with different width of double side skin are investigated， after the analysis．the proposal of selecting the width of double side skin is put forward．[Key words]： bulk carriers；single hull；double hull；reliability1 IntroductionThe LMIS casualty database shows that structural failure contributes with 19％ of the e- conomic losses and 74％ of the fatalities on bulk carriers，so the focus on the structural failure events in present structural reliability study seems justified．The statistical data also shows that app．70％ of the casualties on the bulk carriers are resulted from water ingress due to broadside failure； water ingress due to failure of hatch covers and coamings；water ingress in the fore end．It indicates that the assessment of reliability to ultimate bending strength and broadside on bulk carriers is useful to the safety of ships．A single hull bulk carrier is remoulded to a double hull structure in this paper．The reliability of the two structural forms is compared；the results indicate that the shear stress of broadside has been decreased a lot on the double hull bulk carrier，the probability of structural failure is decreased；the double hull structure come into being box，which strengthens the torsion rigidity at the same time the corruptness on outer side shell can be turned away．Using double hull structure is a useful method to increase the strength of side shell and ensure the safety of the ship，while the effect on longitudinal strength is obsolete．2 The combined bending momentStill water and wave bending moments are to be calculated when assessing the total lon- gitudinal strength，and the combined bending moment is used as the total longitudinal bending moment of the hull．The still water bending moment is varied with different loading condi- tion．Even though at the same loading condition，the value and operating time of the load is modified due to the difference of the load collocations and the sail time，so it should be regarded as stochastic processes．Wave bending moment is the load operating on the hull by the wave，it should be regarded as stochastic process in the design life cycle because of the randomicity of the wave．In actual ship rule such as China CCS，Norway DNV，and SII of IACS，the method of managing the still water and wave bending moments is adding the maximums of the two loads viz．two maximums appear at the same time in the design life cycle．The still water and wave bending moments are not regarded as stochastic processes but stochastic variable by Soding．It shows that the combined method in actual ship criterion is conservative．The Moan u?wnl?=97303.01kN·m； .s 51.6890wkm??AThe reliability index of sagging is：β=4.847 ； here， =0.0.098； =0.763； =1.053 =2.705x kN·m；u?wnl?sM510.51.7420wMkN??AThe results above show that the resistance to bending can be enhanced by remoulding the ship to double hull structure， but obsolete．While the shear stress of side can be decreased to half of primary structure’s (50.7％) by leading in double hull structure，so the result of enhancing the shear strength is very obvious．4 The width of double side skinThe selection of the width of double side skin refers to many aspects，such as structure，cost and construction．etc．Here the effects to result arose by the width are to be discussed．In this paper，1.20m，1.35m，1.50m，1.65m ， and 1.80m are used as the width of double side skin， ultimate bending moment and maximal shear stress are calculated respectively while the other conditions are changeless the calculation process is the same to the condition of 1.20m．Ultimate bending m0ment and maximal shear stress are shown in Tab．5．Relevant curves of ultimate bending moment and maximal shear stress are shown in Fig.3．Tab．5 The effect of the width of double side skinFig．3 The effect of the width of double side skin to ultimatebending moment and maximal shear stressIt can be seen from Tab.5 and Fig.3，when the width of double side skin increases，the location of neutral axis reduces，the ultimate bending moment increases appreciably at the beginning and then reduces，while the maximal shear stress reduces appreciably at the beginning and then increases．So the width of double side skin is not the bigger，the better，but exists an optimum value，here，the ultimate bending moment and maximal shear stress can both reach the optimum values．For the bulk carrier of this paper，the optimum value is about 1.50m．5 Conclusions and suggestionThe following conclusions can be obtained by comparing the difference of two structures center on reliability：(1)For the bulk carriers，the broadside is one of the most slender structures．It endures multiple actions such as shear force，torsion moment and local stress etc．The shear strength of side can be enhanced greatly by remoulding the bulk carrier to double hull structure．It can be made out from this paper，the shear stress of side can be decreased to half of primary structure’s (decreased from 76.987N/ to 39.036N/ )by leading in double hull structure，the shear 2m2strength of side is to be enhanced；(2)Capability resistance to bending can be enhanced to some extent by the double hull structure．The increased extent of reliability index of sagging and hogging is equal on the whole，it is increased 0.021 at hogging，and increased0.024at sagging．According to the example，the ultimate bending moment increased 2.8％（ increased from 3.662x kN·m to 6103.765x kN， m)； 。610(3) When the width of double side skin increased from 1．20m to 1．80m the ultimate bending moment increased at the beginning and then reduced，while the maximal shear stress reduced at the beginning and then increased，so there is an optimum value．It should be noticed，from 1.20m to 1.50m ，the width of double side skin increased 2％ ，but the change extend of shear stress and ultimate bending moment is less than 1/10 of the change of width．At the same time， the cost of ship is increased if the double hull structure is introduced．for this paper，when the width of double side skin is 1.20m，1.50m，1.80m，the cost increased respectively 6％ ，6.5％ and 6.4％.Otherwise，the storage capacity will decrease by introducing double hull structure，the storage capacity decrease about 3％ when the width of double side skin is 1．20m．decrease about 4.5％ when the width of double side skin is 1.50m and 5.8％ when 1.80m．so the width of double side skin need not select the optimum value from the point of economical efficiency．For this paper ,the optimum value calculated is 1.50m，compare to 1.20m，the change extent of ultimate bending moment and maximal shear stress is only 0.2％．while the cost increased 0.5％，at the same time，the storage capacity decreased 1.5％．So the selection of the width is an integrated problem，structure strength，economical efficiency，construction requirement and many other aspects should be considered，the width of double side skin should be tried to dwindle after meeting the requirement of structure strength and construction condition．No need to select the optimum value．外文譯文單雙舷側(cè)散貨船結構可靠性分析專業(yè)論文[摘要]：采用按隨機過程確定的載荷組合彎矩和雙舷側(cè)兩種結構分別計算船舶的極限彎矩和最大剪應力，進行可靠性評估，結果表明雙舷側(cè)結構可以大幅減小舷側(cè)的剪應力，并在一定程度上提高了總縱強度；最后分析了雙舷側(cè)寬度對極限彎矩和最大剪應力的影響，提出了選取雙舷側(cè)寬度值的建議。[關鍵詞] ：散貨船；單舷側(cè)；雙舷側(cè)；可靠性1 介紹由物流管理信息系統(tǒng)的傷亡數(shù)據(jù)庫顯示,結構破壞導致了19%的經(jīng)濟損失和74%的散貨船事故,所以在目前的結構可靠性研究中關注結構破壞事件顯得合情合理。統(tǒng)計數(shù)據(jù)還顯示,散貨船傷亡人數(shù)中的70%都是由于舷側(cè)破壞導致進水;艙口蓋和艙口圍板的破壞導致進水;前端部分進水。它表明對前端和舷側(cè)的抗彎強度的可靠性評估對散貨船安全有很大幫助。在本文介紹單體散貨船改造為雙體船的船舶結構。比較兩個結構形式的可靠性,結果表明,在雙殼散貨船中舷側(cè)的剪切應力已經(jīng)減少了很多,結構破壞的概率卻降低了;雙殼結構形成箱,增強了扭轉(zhuǎn)剛度同時避免舷側(cè)外板的改變。使用雙殼結構對提高舷側(cè)外板的強度和確保船只的安全是一個有用的方法,而對縱向強度的影響很小。2 組合彎矩靜水和波浪彎矩的計算是用來評估總縱強度,并結合彎矩用作總縱向彎矩的船體。在靜水彎矩是隨不同的加載條件改變。即使在同一加載條件，負載的價格和工作時間由于不同的負載配置和航行時間而被修改,所以它應當被視為隨機過程。波浪彎矩是指負載加載在有波浪的船體,它可以被視為設計生命周期中的隨機過程,因為波浪的隨機性。對于實際的船規(guī)如中國CCS、挪威DNV、和國際船級社的SII,其方法是管理靜水和波浪彎矩的最大值是添加兩個加載,即在設計生命周期中出現(xiàn)的兩個最大值。同時靜水和波浪彎矩不能被視為隨機過程但可以是隨機變量.其表明該組合方法在實際船舶標準中是比較保守的。本文采用的是Moan 是波浪系數(shù)。bCw(12)????3/23/210.7530/1010303510.75350/1 0LLw? ???????????????? 最大波浪彎矩在設計生命周期 是,woM（13）?20.1(0.7)(),.9 ()wBCLsaginwo hoiM??? 所以 和 的單殼船體結構可以得到（如表.3 顯示）。,so,結合在下垂和中拱的因素可以由 Matlib 程序計算, =0.7214(sagging): w?=0.6697(hogging).w?表.3 最大靜水彎矩 和波浪彎矩 (單位 kN·m),soM,wo在本文的計算是進行基礎的雙殼改造,所以兩種結構的主尺度沒有多大區(qū)別,但雙殼結構的設計草案有適當?shù)南鄳黾樱鶕?jù)公式(11)到(13),影響組合因素是船的主尺度是長度,船寬和方形系數(shù)而設計草案沒有影響到它,所以組合系數(shù)的兩種結構是平等的。該方法在 Ref,第2章,第七節(jié)用于本文,計算最終彎矩的兩種結構，然后獲得定義為預期價值的極限彎矩 ，估計 的不確定性和不確定性的模型來體現(xiàn)在隨機變量 。根uMu u?據(jù)規(guī)定舷側(cè)的剪切應力在(2001)、船舶結構的分冊,第2部分,第2章，計算舷側(cè)的最大剪切應力。根據(jù)“Manhai”的相關數(shù)據(jù),最大剪切應力出現(xiàn)在船舶到達港口時的隔艙壁載荷,火焰號碼是75,最大剪切力 。驗證表明, 在下垂位置處的靜水剪切和波浪剪4.5710sFkN??切的總和是最大的,其值為 結果的細節(jié)顯示在表.4:6表.4 極限彎矩和最大剪切應力可靠性指標的單殼散貨船總縱向彎矩的條件下中拱是使用遺傳算法計算, β=5.356；這里， =0.048； ,=0.764； =0.978； =97282.9kN·m；u?wnl?sM。51.680wMkNm??A可靠性指標的下垂是：β=4.680； =0.101； =0.762； =1.052 =2.700xuw?nl sMkN·m； 。505.791wk可靠性指標的雙殼散貨船總縱向彎矩的條件下中拱是：β=5.37l； =0.048； =0.764； =0.978; =97303.01kN·m；u?wnl?s。51.6890wMkNm??A可靠性指標的下垂是：β=4.847； =0.0.098； =0.763； =1.053 =2.705xuw?nlsMkN·m； 。505.7421wk上面的結果顯示,抗彎曲能力能提高船體改造為雙殼結構,但太過時。通過雙殼雙殼結構，一側(cè)的剪切應力可以減少到原來主要結構的的一半(50.7%),所以提高其抗剪強度的結果是顯而易見的。4 雙舷側(cè)的寬度雙舷側(cè)寬度的選擇指的是多方面的,如結構、成本和施工等。在這里,討論影響結果引發(fā)的寬度,在本文，1.20米、1.35米、1.50米、1.65米和1.80米用作雙舷側(cè)的寬度,極限彎矩和最大剪切應力分別計算，而其他條件都不變的計算過程是相同的情況1.20 m。極限彎矩和最大剪切應力顯示在表.5，相關曲線的極限彎矩和最大剪切應力是圖.3 所示。表.5 雙舷側(cè)寬度的影響圖.3 極限彎矩和最大剪切應力對雙舷側(cè)的影響表.5和圖.3可以看出,當雙舷側(cè)的寬度增加時,中性軸的位置減少,極限彎矩開始明顯地增加,而后又減少,而最大剪切應力剛開始明顯地降低,而后開始增加。所以雙舷側(cè)的寬度不是越大,效果越好,而是存在一個最佳值,在這里,極限彎矩和最大剪切應力都能達到最優(yōu)值。對于本文的散貨船,最優(yōu)值約為1.50米。5 結論和建議以下結論可以在可靠性上通過比較兩種結構中心的差異:(1) 對散貨船,舷側(cè)是其中最細長的結構，存到多個操作如剪切力、扭矩和局部應力等。通過重塑散貨船為雙殼結構，舷側(cè)的抗剪強度能大大提高。它可以從本文得出,舷側(cè)的剪切應力可以減少到主要結構的一半(從 76.987N/ 減少到39.036N/ )2m2m通過引入雙殼結構,其抗剪強度的一邊是要增強的；(2) 性能在某種程度上可以增強雙殼結構的抗彎曲性，中垂和中拱的可靠性指標的增加程度總體上是相等的，在中拱它是增加0.021,而在中垂增加了0.024。根據(jù)示例中,極限彎矩增加了2.8%(從3.662× kN·m增加到3.765× kN)；610610(3) 當雙舷側(cè)的寬度從1.20m增加到1.80m，最終的彎矩開始先增加然后減少,而最大剪切應力先下降然后增加,所以有一個最佳價值。應該注意到,從1.20米到1.50米,雙舷側(cè)的寬度增加了2%,但是更改的剪切應力和極限彎矩的延伸不到寬度的改變的1/10。與此同時, 如果是雙殼結構，介紹了船舶成本的增加。本文中，當雙舷側(cè)的寬度是1.20米、1.50米、1.80米，成本分別增加了6%、6.5%和6.4%。另外,通過引入雙殼結構后存儲容量會降低, 當雙舷側(cè)寬度是1.20 m時存儲容量減少約3%，當雙舷側(cè)的寬度是1.50米時減少約4.5%和當1.80米時減少5.8%。所以雙舷側(cè)的寬度不需要選擇最優(yōu)值的一點來自于經(jīng)濟效率。對于本文，最優(yōu)價值計算是1.50米，與1.20米相比,極限彎矩和最大剪切應力的變化程度只有0.2%。雖然成本增加了0.5%,同時,但存儲容量下降了1.5%。所以寬度的選擇是一個綜合的問題,結構強度、經(jīng)濟效益、施工要求和許多其他方面應該考慮, 在會議后結構強度和施工條件的需求下雙舷側(cè)的寬度應該盡量減少，不需要選擇最優(yōu)值。