Abstract: The acting force of sea ice is more important to off shore structures than sea wave force in Bobai Bay,China.The working stress of tubular joints of platform structure very closely related to rupture forms of sea ice.The rupture forms of sea ice are mainly crushing,buckling and bending.It used to calculate the stress only according to one of the rupture forms.Now some rupture forms are considered together in this paper.In the present specification,the fatigue life curve of off shore structure steel under condition of low temperature and ice load is not given.In this paper,based on the experimental results of fatigue crack propagation under low temperature and random ice load by Petroleum University,the fatigue life curve and its parameters are given.A new method of fatigue life calculation of tubular joints is put forward in this paper.

Key words: offshore platform, tubular joint, fatigue rupture, low temperature, ice load

摘要： 我国渤海的海冰对海上结构物的作用力,较波浪力尤为重要.海冰作用下,平台管节点构件承受的应力与海冰的破坏形式密切相关.海冰的破坏形式主要有挤压、屈曲、弯曲等.过去在计算应力时,只是按照一种破坏形式;本文综合起来考虑几种破坏形式并存.现有规范中,未给出低温冰载荷作用下的海洋结构用钢的疲劳寿命曲线,本文根据石油大学进行低温随机冰载作用下疲劳裂纹扩展试验的结果,给出了疲劳寿命曲线及其参数.在上述基础上,文章提出了管节点疲劳寿命计算的一种新方法.

关键词: 海上平台, 管节点, 疲劳破坏, 低温, 冰载荷