船舶损伤后船体剩余强度.doc
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船舶损伤后船体剩余强度,摘要船舶的剩余强度是衡量船体结构安全可靠性的重要指标，合理评估损伤船舶对外载荷的极限承载能力，有助于更高效的开展船体结构设计，减少事故损失。本文在研究了损伤后船体梁的浮态及载荷效应的基础上，基于共同规范，编制了简化逐步破坏法极限强度计算程序；采用非线性有限元软件abaqus，分析了极限强度有限元仿真技术，以12,000...
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摘 要
船舶的剩余强度是衡量船体结构安全可靠性的重要指标，合理评估损伤船舶对外载荷的极限承载能力，有助于更高效的开展船体结构设计，减少事故损失。
本文在研究了损伤后船体梁的浮态及载荷效应的基础上，基于共同规范，编制了简化逐步破坏法极限强度计算程序；采用非线性有限元软件Abaqus，分析了极限强度有限元仿真技术，以12,000DWT油船为例，对其在不同载况、不同破舱组合、不同横倾角下的剩余强度进行了分析；开展了小尺度损伤结构物极限强度实验，并与本文所编程序及非线性有限元计算结果进行了对比研究。主要内容及结论如下：
(1) 整理出了考虑船舶损伤后浮态、载荷效应变化，并计及损伤船体梁在初始横倾角影响下，产生非对称弯曲的，分别基于简化逐步破坏法和非线性有限元法的损伤后船体梁剩余强度评估方法。
(2) 编制的简化逐步破坏法极限强度计算程序具有参数输入简单，可自动划分单元等优点，结合内置的浮态载荷计算模块，实现了考虑浮态及载荷效应的极限强度的快速计算，通过算例及模型实验验证了该程序具有一定的计算精度。
(3) 基于Abaqus软件进行了极限强度的非线性有限元法研究，分析了有限元模型化技术（包括求解方法、建模范围、腐蚀余量等）对计算结果的影响，提出了适于损伤船体梁极限承载能力计算的模型化技术，并得到了12,000DWT油船在不同浮态和损伤情况下的损伤模式和极限承载能力。
(4) 开展了完整结构和不同位置破损结构小尺度模型的极限强度实验，实验结果与有限元法及简化逐步破坏法计算结果吻合较好，评估了不同损伤位置对结构的变形模式和极限承载能力的影响情况。
(5) 损伤船舶的浮态会对剩余强度产生较大的影响，传统的基于正浮状态的剩余强度评估易得出偏危险的结果。损伤船体梁的剩余强度总体上随着横倾角的增加呈下降趋势，在大横倾角情况下尤为明显，且中垂工况较中拱工况下降更快。局部凹陷也会对损伤船体梁的极限承载能力产生一定影响，特别是船底凹陷。
(6) 基于系统的模型化技术研究的非线性有限元法在进行剩余强度评估时能够获得较为精确的损伤船体梁极限承载能力及其失效模式，而简化逐步破坏法则具有计算快捷的优势，但在大倾角下易得出偏危险的结果。
关键词：破损船舶；剩余强度；极限强度；简化逐步破坏法；非线性有限元法
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..
船舶的剩余强度是衡量船体结构安全可靠性的重要指标，合理评估损伤船舶对外载荷的极限承载能力，有助于更高效的开展船体结构设计，减少事故损失。
本文在研究了损伤后船体梁的浮态及载荷效应的基础上，基于共同规范，编制了简化逐步破坏法极限强度计算程序；采用非线性有限元软件Abaqus，分析了极限强度有限元仿真技术，以12,000DWT油船为例，对其在不同载况、不同破舱组合、不同横倾角下的剩余强度进行了分析；开展了小尺度损伤结构物极限强度实验，并与本文所编程序及非线性有限元计算结果进行了对比研究。主要内容及结论如下：
(1) 整理出了考虑船舶损伤后浮态、载荷效应变化，并计及损伤船体梁在初始横倾角影响下，产生非对称弯曲的，分别基于简化逐步破坏法和非线性有限元法的损伤后船体梁剩余强度评估方法。
(2) 编制的简化逐步破坏法极限强度计算程序具有参数输入简单，可自动划分单元等优点，结合内置的浮态载荷计算模块，实现了考虑浮态及载荷效应的极限强度的快速计算，通过算例及模型实验验证了该程序具有一定的计算精度。
(3) 基于Abaqus软件进行了极限强度的非线性有限元法研究，分析了有限元模型化技术（包括求解方法、建模范围、腐蚀余量等）对计算结果的影响，提出了适于损伤船体梁极限承载能力计算的模型化技术，并得到了12,000DWT油船在不同浮态和损伤情况下的损伤模式和极限承载能力。
(4) 开展了完整结构和不同位置破损结构小尺度模型的极限强度实验，实验结果与有限元法及简化逐步破坏法计算结果吻合较好，评估了不同损伤位置对结构的变形模式和极限承载能力的影响情况。
(5) 损伤船舶的浮态会对剩余强度产生较大的影响，传统的基于正浮状态的剩余强度评估易得出偏危险的结果。损伤船体梁的剩余强度总体上随着横倾角的增加呈下降趋势，在大横倾角情况下尤为明显，且中垂工况较中拱工况下降更快。局部凹陷也会对损伤船体梁的极限承载能力产生一定影响，特别是船底凹陷。
(6) 基于系统的模型化技术研究的非线性有限元法在进行剩余强度评估时能够获得较为精确的损伤船体梁极限承载能力及其失效模式，而简化逐步破坏法则具有计算快捷的优势，但在大倾角下易得出偏危险的结果。
关键词：破损船舶；剩余强度；极限强度；简化逐步破坏法；非线性有限元法
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..
