LNG船纵骨端部表面裂纹疲劳扩展寿命计算  

Fatigue Life Calculation of Surface Cracks at the Longitudinal Stiffener End Joints of an LNG Vessel

作　　者：阮宏宝 黄小平[1] RUAN Hongbao;HUANG Xiaoping(Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学高新船舶与深海开发装备协同创新中心,上海200240

出　　处：《船舶与海洋工程》2020年第2期18-25,31,共9页Naval Architecture and Ocean Engineering

摘　　要：基于断裂力学的裂纹扩展方法预报液舱纵骨端部的疲劳寿命。采用有限元软件对液舱纵骨端部节点处表面裂纹应力强度因子进行系列计算,并在BS7910经验公式的基础上拟合出趾端的应力强度因子修正系数经验公式。将采用该公式得到的结果与有限元计算结果相对比,结果表明二者能较好地吻合,该公式可应用到类似端部结构裂纹扩展应力强度因子的计算中。按挪威船级社(Det Norske Veritas,DNV)规范的要求组合热点主应力幅值,并按降序对各载荷块构造液舱疲劳热点载荷谱,结合修正公式系数经验计算液舱纵骨端部趾端的裂纹扩展寿命,预报的疲劳寿命满足要求。This paper forecasts the fatigue life of the longitudinal stiffener end joins of liquid tanks based on the fracture propagation method of fracture mechanics.A series of computations on the stress intensity factors of surface cracks at the longitudinal stiffener end joints of a liquid tank carried out with the finite element software and the empirical formula of BS7910 leads to a new empirical formula for the correction coefficients of weld toe stress intensity factors.The results from the formula agree well with those obtained by the finite element calculations,which can be applied to the calculation of crack propagation stress intensity factors of similar end joint structures.The combinations of hot spot principal stress amplitudes are chosen according to DNV(Det Norske Veritas)regulations,and the load spectrum of the hot spot in the tank is constructed by arranging the load segments in descending order.The crack propagation fatigue life of the weld toe at the longitudinal stiffener end joints in the liquid tank is predicted using the empirical formula proposed in this paper,and the obtained fatigue life can meet the requirement.

关 键 词：液舱纵骨端部 表面裂纹 应力强度因子 裂纹扩展 疲劳寿命 

分 类 号：U661.43[交通运输工程—船舶及航道工程] U674.133.3[交通运输工程—船舶与海洋工程]