【作者】 郑雷；

【导师】 黄小平； 李小灵；

【作者基本信息】 上海交通大学 ， 船舶与海洋工程（专业学位）， 2018， 硕士

【摘要】 液化气船用于海上运输大宗液化天然气(LNG)、液化石油气(LPG)、石化产品、化学品气体和液氨等。目前,液化气体运输船通常采用薄膜型和独立型两种围护系统。近年来,因其相对低廉的成本、简易的建造工艺和较低的蒸发率,业界对B型独立液舱表现出愈加浓厚的兴趣。目前,国内对该类型液舱的研究尚出于起步阶段,公开发表的关于其裂纹扩展和泄漏分析的资料少之又少,因此对该问题进行研究具有重要意义。此外,已生效的新IGC明确要求C型独立液舱外板表面初始微裂纹在运营周期内扩展深度不应超过外板厚度的一半。虽然压力容器的设计蒸汽压力公式中已经通过动态膜应力考虑了该部分影响,但当其尺寸非常大(如单个液舱容积达30,000m~3)时,结构的性能会存在不确定性,出于安全的考虑,需要对结构在实际交变载荷作用下的断裂力学性能进行校核。鉴于此,本文在消化吸收断裂力学理论知识、LBB准则及液化气船相关规范规则的基础上,形成了一套完整可行的液化气船低温独立液舱裂纹扩展与泄漏分析计算方法;采用VB语言开发完成了一款专用计算软件,采用该软件对某型实船进行计算,并对计算结果进行分析,得出若干结论。更多还原

【Abstract】 Liquefied gas carrier is mainly used to transport LNG,LPG,petrochemical products,chemical gas,liquid ammonia,etc.Membrane or independent cargo container system is usually used for liquefied gas carrier.In recent years,because of its relatively low cost,simple manufacturing process and lower evaporation rate,the industry shows more and more interest to Type-B independent cargo tank.At present,the research on Type-B tank is still in its infancy,and the public information is very few,so it is of great significance to study this subject.In addition,the new IGC explicitly requires that an initial surface flaw will not propagate more than half the thickness of the shell during the lifetime of the tank.Although the dynamic membrane stress has been considered in the design of pressure vessel,the performance of structure is uncertain when its size is very large.For safety reasons,the fracture mechanics performance of the structure under alternating loading needs to be evaluated.In view of this,based on the fracture mechanics,LBB criterion and relevant rules and specification of gas carrier,a completely method of crack propagation and leakage analysis for independent cargo tank has been form.In this paper,special calculation software is developed with VB language and used to calculate the actual ship,and the calculation results are analyzed and some conclusions are drawn.更多还原