冰区海洋平台构件的模糊疲劳可靠性分析

为便于冰区海上固定采油平台的设计和对其在服役期间的安全可靠性进行评估 ,运用模糊数学理论和疲劳寿命试验 ,提出了冰区海洋平台构件的安全疲劳寿命计算及其可靠性分析的方法。给出了冰区海浪及海冰载荷作用于平台构件上的随机疲劳应力幅的计算方法 ,分析了平台构件的疲劳累积损伤 ,提出了考虑模糊性之后对Min er法则的修正。据此 ,给出了安全疲劳寿命的估算方法 ,建立了新的模糊疲劳可靠性分析模型。按照此模型 ,给出了平台服役期间构件动态模糊疲劳可靠度的计算方法。疲劳寿命试验及计算实例表明 ,与采用常规的确定性Miner法则计算结果相比 ,按照该文方法计算得出的疲劳寿命更接近于疲劳寿命试验结果。

Fuzzy fatigue reliability analysis on structural members of offshore platform in ice area

In order to design offshore fixed production platforms used in ice area and assess their safety reliability in service, the methods for estimating the safety fatigue life and analyzing the reliability of structural members of offshore platform in ice area were proposed by means of fuzzy mathematics and fatigue life experiments. The calculation method for random fatigue stress range resulted from sea wave loads and sea ice loads in ice area was given, and the analysis method for fatigue cumulative damage of structural members of offshore platform was provided. The Miner rule was modified in consideration of its fuzziness. Based upon the corrected Miner rule, an estimation method for safety fatigue life was developed. A new analysis model for fuzzy fatigue reliability was established. According to this new model, an assessment method for fuzzy fatigue reliability of structural members of offshore platform in service was provided. The fatigue life experiments and practical calculation example show that the calculated result of the fatigue life using the new calculation method is more close to the experimental result than that by means of ordinary certainty Miner rule.