基于S-N曲线的深水半潜平台疲劳寿命分析

Fatigue Analysis of Deepwater Semi-submersible Platform Based on S-N Approach

深水半潜平台工作环境恶劣,造价成本高,为保证安全工作,有必要对其进行疲劳寿命分析。首先利用SESAM软件建立目标平台整体模型并分析总体结构响应。然后根据平台总体结构响应计算结果,选取立柱与横撑连接处、立柱外板与上甲板连接处两个关键节点,建立关键节点有限元模型,计算其热点应力。最后采用S-N曲线分析该平台在中国南海环境条件下的疲劳寿命。分析结果显示该平台疲劳寿命符合规范要求,但立柱与横撑连接处的疲劳寿命偏低,应加强日常检修和维护。

Deepwater semi-submersible platform works in bad environment conditions with high cost, so it is necessary to do fatigue analysis to make sure it works safely. Firstly, the model of platform was made and the response of the global structure was calculated based on SESAM. According to overall response result, column and brace connection ＆ column and upper deck connection were chosen as key joint. The fine FEA model of key joint was made and the hotspot stress was calculated. Finally, the fatigue life of platform was calculated based on S-N approach in South China Sea. The result shows that the platform could meet ABS rules demand but there is a low fatigue life at the column and the brace connection of the platform, so the strengthening daily repair and maintenance is necessary.