基于谱分析法的桩腿疲劳寿命研究

摘要

基于S－N曲线和Miner线性累计损伤理论，采用谱分析法对海洋平台的桩腿典型节点的疲劳强度进行了评估；通过采用等效梁单元、梁单元、线性弹簧单元和线弹性基础模型来模拟船体、桩腿、船体－桩腿和桩靴－土壤等实体，利用stokes fifth-order波浪理论来分析计算不同浪向角及波浪频率下典型节点的热点应力传递函数；并采用中国南海波浪散布图，对桩腿各典型节点进行疲劳强度评估分析；根据CCS规范计算得出海洋平台桩腿管节点处的波劳寿命为41．3a，位于水面附近．分析结果可为同类型平台桩腿的结构设计和开发提供一定的参考．%Based on the SN curve and Miner linear cumulative damage theory,the fatigue of offshore platform leg typical nodes were evaluated by the use of spectral analysis.We use the equivalent beam elements,beam ele-ments,linear elastic spring elements and basic linear model to simulate the hull,leg,hull-leg,shoe-soil and other entities,and Stokes fifth-order wave theory to calculate the stress transfer function of hot corners for typical nodes at different wave angles and wave frequency.We also use the South China Sea waves scatter diagram to make fatigue strength assessment analysis for typical nodes of each leg.According to the CCS code,the fatigue life of offshore platform pile and leg tube joint is 41.3a,which is located near the surface of the water.The re-sults can provide reference for the design and development of the same type of platform legs.