摘 要
船舶的剩余強(qiáng)度是衡量船體結(jié)構(gòu)安全可靠性的重要指標(biāo)，合理評估損傷船舶對外載荷的極限承載能力，有助于更高效的開展船體結(jié)構(gòu)設(shè)計(jì)，減少事故損失。
本文在研究了損傷后船體梁的浮態(tài)及載荷效應(yīng)的基礎(chǔ)上，基于共同規(guī)范，編制了簡化逐步破壞法極限強(qiáng)度計(jì)算程序；采用非線性有限元軟件Abaqus，分析了極限強(qiáng)度有限元仿真技術(shù)，以12,000DWT油船為例，對其在不同載況、不同破艙組合、不同橫傾角下的剩余強(qiáng)度進(jìn)行了分析；開展了小尺度損傷結(jié)構(gòu)物極限強(qiáng)度實(shí)驗(yàn)，并與本文所編程序及非線性有限元計(jì)算結(jié)果進(jìn)行了對比研究。主要內(nèi)容及結(jié)論如下：
(1) 整理出了考慮船舶損傷后浮態(tài)、載荷效應(yīng)變化，并計(jì)及損傷船體梁在初始橫傾角影響下，產(chǎn)生非對稱彎曲的，分別基于簡化逐步破壞法和非線性有限元法的損傷后船體梁剩余強(qiáng)度評估方法。
(2) 編制的簡化逐步破壞法極限強(qiáng)度計(jì)算程序具有參數(shù)輸入簡單，可自動劃分單元等優(yōu)點(diǎn)，結(jié)合內(nèi)置的浮態(tài)載荷計(jì)算模塊，實(shí)現(xiàn)了考慮浮態(tài)及載荷效應(yīng)的極限強(qiáng)度的快速計(jì)算，通過算例及模型實(shí)驗(yàn)驗(yàn)證了該程序具有一定的計(jì)算精度。
(3) 基于Abaqus軟件進(jìn)行了極限強(qiáng)度的非線性有限元法研究，分析了有限元模型化技術(shù)（包括求解方法、建模范圍、腐蝕余量等）對計(jì)算結(jié)果的影響，提出了適于損傷船體梁極限承載能力計(jì)算的模型化技術(shù)，并得到了12,000DWT油船在不同浮態(tài)和損傷情況下的損傷模式和極限承載能力。
(4) 開展了完整結(jié)構(gòu)和不同位置破損結(jié)構(gòu)小尺度模型的極限強(qiáng)度實(shí)驗(yàn)，實(shí)驗(yàn)結(jié)果與有限元法及簡化逐步破壞法計(jì)算結(jié)果吻合較好，評估了不同損傷位置對結(jié)構(gòu)的變形模式和極限承載能力的影響情況。
(5) 損傷船舶的浮態(tài)會對剩余強(qiáng)度產(chǎn)生較大的影響，傳統(tǒng)的基于正浮狀態(tài)的剩余強(qiáng)度評估易得出偏危險的結(jié)果。損傷船體梁的剩余強(qiáng)度總體上隨著橫傾角的增加呈下降趨勢，在大橫傾角情況下尤為明顯，且中垂工況較中拱工況下降更快。局部凹陷也會對損傷船體梁的極限承載能力產(chǎn)生一定影響，特別是船底凹陷。
(6) 基于系統(tǒng)的模型化技術(shù)研究的非線性有限元法在進(jìn)行剩余強(qiáng)度評估時能夠獲得較為精確的損傷船體梁極限承載能力及其失效模式，而簡化逐步破壞法則具有計(jì)算快捷的優(yōu)勢，但在大傾角下易得出偏危險的結(jié)果。

關(guān)鍵詞：破損船舶；剩余強(qiáng)度；極限強(qiáng)度；簡化逐步破壞法；非線性有限元法
Abstract
The residual strength of ship hull is an important index expressing the safety and reliability of the structure. Reasonable assessment of the damaged ship’s ultimate carrying capacity to the external load is helpful to carry out hull structure design and reduce accident losses.
After studying the floating state and load effect of damaged hull girder, a ultimate strength calculation program using Smith’s method based on Common Structural Rules was complied; The numerical simulation technology of ultimate strength calculation with Nonlinear Finite Element software Abaqus was studied, and a 12,000DWT tanker was took as a study case, its residual strength in condition of different load condition, different combination of flooding compartment and different heeling angle were calculated; A ultimate strength experiment of small scale damaged structures was carried out, the experimental results and calculation results were compared. Main content and conclusions are as follows:
(1) A relatively complete damaged ship’s residual strength assessment process based on Smith's method and Nonlinear Finite Element method has been sorted out, which considered the change of floating state and load effect, and took the influence of initial heeling angle to the damaged hull girder under asymmetric bending into account.
(2) The ultimate strength calculation program has simplified the input parameters of hull girder’s cross-section, and realized the automatic division of the element, along with the floating state and load calculation program, can carry out the rapid assessment of damaged hull girder’s residual strength, the example and model test have verified the program has a certain accuracy.
(3) Ultimate strength calculation using Nonlinear Finite Element method with Abaqus was carried out, while numerical simulation technology (including solving method, compartment length, corrosion addition and etc.) was studied firstly, then a solution for ultimate carrying capacity calculation of damaged hull girder was proposed, and related calculation results of 12,000DWT tanker in condition of different floating state and damage were derived.
(4) The ultimate strength experiment of intact and different location of damaged structure was carried out, experimental results and calculation results matched well, and the influence of different location of damage to deformation mode and ultimate carrying capacity was eva luated.
(5) The floating state of damaged ship will have a great influence to the residual strength, and the traditional residual strength assessment in upright floating state tends to come to dangerous conclusions. The residual strength of damaged hull girder declines with the increase of heeling angle in general, while in case of big heeling angle, it's particularly evident, and sagging condition is in a more dangerous situation. Local dent will have impact to ultimate carrying capacity of damaged hull girder, especially in bottom dented condition.
(6) The Nonlinear Finite Element method based on systematic numerical simulation technology can get..