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to increase the strength of side shell and ensure the safety of the ship，while the effect on longitudinal strength is obsolete．2 The combined bending momentStill water and wave bending moments are to be calculated when assessing the total lon- gitudinal strength，and the combined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(jié)構(gòu)可靠性分析專業(yè)論文[摘要]：采用按隨機(jī)過程確定的載荷組合彎矩和雙舷側(cè)兩種結(jié)構(gòu)分別計(jì)算船舶的極限彎矩和最大剪應(yīng)力，進(jìn)行可靠性評估，結(jié)果表明雙舷側(cè)結(jié)構(gòu)可以大幅減小舷側(cè)的剪應(yīng)力，并在一定程度上提高了總縱強(qiáng)度；最后分析了雙舷側(cè)寬度對極限彎矩和最大剪應(yīng)力的影響，提出了選取雙舷側(cè)寬度值的建議。[關(guān)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(jié)構(gòu)破壞導(dǎo)致了19%的經(jīng)濟(jì)損失和74%的散貨船事故,所以在目前的結(jié)構(gòu)可靠性研究中關(guān)注結(jié)構(gòu)破壞事件顯得合情合理。統(tǒng)計(jì)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(dǎo)致進(jìn)水;艙口蓋和艙口圍板的破壞導(dǎo)致進(jìn)水;前端部分進(jìn)水。它表明對前端和舷側(cè)的抗彎強(qiáng)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(jié)構(gòu)。比較兩個(gè)結(jié)構(gòu)形式的可靠性,結(jié)果表明,在雙殼散貨船中舷側(cè)的剪切應(yīng)力已經(jīng)減少了很多,結(jié)構(gòu)破壞的概率卻降低了;雙殼結(jié)構(gòu)形成箱,增強(qiáng)了扭轉(zhuǎn)剛度同時(shí)避免舷側(cè)外板的改變。使用雙殼結(jié)構(gòu)對提高舷側(cè)外板的強(qiáng)度和確保船只的安全是一個(gè)有用的方法,而對縱向強(qiáng)度的影響很小。2 組合彎矩靜水和波浪彎矩的計(jì)算是用來評估總縱強(qiáng)度,并結(jié)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(fù)載的價(jià)格和工作時(shí)間由于不同的負(fù)載配置和航行時(shí)間而被修改,所以它應(yīng)當(dāng)被視為隨機(jī)過程。波浪彎矩是指負(fù)載加載在有波浪的船體,它可以被視為設(shè)計(jì)生命周期中的隨機(jī)過程,因?yàn)椴ɡ说碾S機(jī)性。對于實(shí)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(gè)加載,即在設(shè)計(jì)生命周期中出現(xiàn)的兩個(gè)最大值。同時(shí)靜水和波浪彎矩不能被視為隨機(jī)過程但可以是隨機(jī)變量.其表明該組合方法在實(shí)際船舶標(biāo)準(zhǔn)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(shè)計(jì)生命周期 是,woM（13）?20.1(0.7)(),.9 ()wBCLsaginwo hoiM??? 所以 和 的單殼船體結(jié)構(gòu)可以得到（如表.3 顯示）。,so,結(jié)合在下垂和中拱的因素可以由 Matlib 程序計(jì)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(jì)算是進(jìn)行基礎(chǔ)的雙殼改造,所以兩種結(jié)構(gòu)的主尺度沒有多大區(qū)別,但雙殼結(jié)構(gòu)的設(shè)計(jì)草案有適當(dāng)?shù)南鄳?yīng)增加，根據(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(shè)計(jì)草案沒有影響到它,所以組合系數(shù)的兩種結(jié)構(gòu)是平等的。該方法在 Ref,第2章,第七節(jié)用于本文,計(jì)算最終彎矩的兩種結(jié)構(gòu)，然后獲得定義為預(yù)期價(jià)值的極限彎矩 ，估計(jì) 的不確定性和不確定性的模型來體現(xiàn)在隨機(jī)變量 。根uMu u?據(jù)規(guī)定舷側(cè)的剪切應(yīng)力在(2001)、船舶結(jié)構(gòu)的分冊,第2部分,第2章，計(jì)算舷側(cè)的最大剪切應(yīng)力。根據(jù)“Manhai”的相關(guān)數(shù)據(jù),最大剪切應(yīng)力出現(xiàn)在船舶到達(dá)港口時(shí)的隔艙壁載荷,火焰號碼是75,最大剪切力 。驗(yàn)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(jié)果的細(xì)節(jié)顯示在表.4:6表.4 極限彎矩和最大剪切應(yīng)力可靠性指標(biāo)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(jì)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(biāo)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(biāo)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(biāo)的下垂是：β=4.847； =0.0.098； =0.763； =1.053 =2.705xuw?nlsMkN·m； 。505.7421wk上面的結(jié)果顯示,抗彎曲能力能提高船體改造為雙殼結(jié)構(gòu),但太過時(shí)。通過雙殼雙殼結(jié)構(gòu)，一側(cè)的剪切應(yīng)力可以減少到原來主要結(jié)構(gòu)的的一半(50.7%),所以提高其抗剪強(qiáng)度的結(jié)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(jié)構(gòu)、成本和施工等。在這里,討論影響結(jié)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(yīng)力分別計(jì)算，而其他條件都不變的計(jì)算過程是相同的情況1.20 m。極限彎矩和最大剪切應(yīng)力顯示在表.5，相關(guān)曲線的極限彎矩和最大剪切應(yīng)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(yīng)力對雙舷側(cè)的影響表.5和圖.3可以看出,當(dāng)雙舷側(cè)的寬度增加時(shí),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(yīng)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(gè)最佳值,在這里,極限彎矩和最大剪切應(yīng)力都能達(dá)到最優(yōu)值。對于本文的散貨船,最優(yōu)值約為1.50米。5 結(jié)論和建議以下結(jié)論可以在可靠性上通過比較兩種結(jié)構(gòu)中心的差異:(1) 對散貨船,舷側(cè)是其中最細(xì)長的結(jié)構(gòu)，存到多個(gè)操作如剪切力、扭矩和局部應(yīng)力等。通過重塑散貨船為雙殼結(jié)構(gòu)，舷側(cè)的抗剪強(qiáng)度能大大提高。它可以從本文得出,舷側(cè)的剪切應(yīng)力可以減少到主要結(jié)構(gòu)的一半(從 76.987N/ 減少到39.036N/ )2m2m通過引入雙殼結(jié)構(gòu),其抗剪強(qiáng)度的一邊是要增強(qiáng)的；(2) 性能在某種程度上可以增強(qiáng)雙殼結(jié)構(gòu)的抗彎曲性，中垂和中拱的可靠性指標(biāo)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(dāng)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(yīng)力先下降然后增加,所以有一個(gè)最佳價(jià)值。應(yīng)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(yīng)力和極限彎矩的延伸不到寬度的改變的1/10。與此同時(shí), 如果是雙殼結(jié)構(gòu)，介紹了船舶成本的增加。本文中，當(dāng)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(jié)構(gòu)后存儲容量會降低, 當(dāng)雙舷側(cè)寬度是1.20 m時(shí)存儲容量減少約3%，當(dāng)雙舷側(cè)的寬度是1.50米時(shí)減少約4.5%和當(dāng)1.80米時(shí)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(diǎn)來自于經(jīng)濟(jì)效率。對于本文，最優(yōu)價(jià)值計(jì)算是1.50米，與1.20米相比,極限彎矩和最大剪切應(yīng)力的變化程度只有0.2%。雖然成本增加了0.5%,同時(shí),但存儲容量下降了1.5%。所以寬度的選擇是一個(gè)綜合的問題,結(jié)構(gòu)強(qiáng)度、經(jīng)濟(jì)效益、施工要求和許多其他方面應(yīng)該考慮, 在會議后結(jié)構(gòu)強(qiáng)度和施工條件的需求下雙舷側(cè)的寬度應(yīng)該盡量減少，不需要選擇最優(yōu)值。