基于实测应变的现役导管架平台疲劳损伤分析

Fatigue Damage Analysis of Jacket Platform Based on Measured Strain

为评估导管架平台剩余疲劳寿命,以南海某现役导管架平台为研究对象,利用电阻应变传感器对结构高应力区进行应力监测,获取测点处应力时程数据,将其乘以应力集中因数可得到节点的热点应力时程数据。采用雨流计数法获得疲劳应力循环幅值和相应循环次数。参照DNV推荐的管节点S-N曲线,基于Palmgren-Miner线性疲劳累积损伤准则,得到热点处的疲劳损伤度,并结合海上实测的时间长度,预测导管架平台的疲劳寿命。由结果可知,评价节点的疲劳强度能够满足平台安全性能要求,且基于监测数据的预测寿命低于设计海况下的寿命。

In order to evaluate the remaining fatigue life of jacket platform,taken the jacket platform in Nanhai as the research object,the resistance strain sensor is used to monitor the stress in the high-stress area of the structure,and the stress time history data at the measuring points are obtained.These data are multiplied by the stress concentration factor to get the hot spot stress time history data of the node.The rain flow counting method is used to obtain the fatigue stress cycle amplitude and the corresponding cycle times.Referring to the S-N curve of pipe joints recommended by DNV,and based on the Palmgren-Miner linear fatigue cumulative damage criterion,the fatigue damage degree at the hot spot is obtained,and combined with the measured time at sea,the fatigue life of the jacket platform is predicted.The analysis results show that the fatigue strength of the evaluation node can meet the safety performance requirements of the platform,and the predicted life based on the monitoring data is lower than the life under design sea conditions.