基于台风验证载荷的平台时变可靠性分析与更新

采用泊松过程对台风载荷进行描述,结合抗力衰减函数建立平台时变可靠性分析模型,确定基于验证载荷的平台抗力后验分布函数,从而实现平台可靠性更新;根据台风作用后平台状态与台风载荷分布函数确定验证载荷概率模型。以我国南海东北区块一海洋平台为研究对象,对平台的时变可靠性进行分析与更新,考察平台损伤极限承载能力比CQ与验证时间对可靠性更新效果的影响。结果表明:台风验证载荷能够对结构冗余度较低的海洋平台时变可靠性更新起到明显效果,且反映平台结构冗余度的CQ值越大更新效果越明显;验证载荷出现时间越晚,在初期的更新效果越明显,这个时间大约持续5 a,随后不同时刻验证载荷的更新效果趋于相同。

Time-dependent reliability analysis and updating of offshore platforms based on typhoon proof load

The typhoon load process was described by a Poisson point process according to its characteristics,and combined with resistance degradation function,a time-dependent reliability analysis model was presented.The posterior distribution of resistance was determined by conditional probability theory.Then the reliability updating model was developed through the modified resistance model.The probability model of proof load was determined by the platform performance in typhoon and the long-term distribution of typhoon load.Finally,the time-dependent reliability of an offshore platform in south China Sea was analyzed,and the influence of the ratio of platform damage resistance to ultimate resistance CQ and occurrence time of proof load on the reliability updating effect was investigated.The results show that if the structural redundancy is low,the updating effect of proof load on time-dependent reliability is obvious,and the updating effect becomes more obvious with CQ increasing.When the occurrence time of proof load is later,the updating effect is more obvious at the early stage,and the stage will last for 5 years.Subsequently,the difference of updating effect becomes negligible.