首次穿越失效方法用于评价海底管跨的可靠度

应用随机振动的首次穿越理论和可靠度理论对波浪作用下的海底管跨进行疲劳可靠度分析。基于断裂力学原理建立疲劳失效准则,海底管跨的疲劳失效可以看成首次穿越问题。将管跨服役期内的长期海况看成由若干离散短期海况组成,通过模态分析方法确定海底管跨在各海况下的应力响应。根据首次穿越理论的泊松模型,计算各海况下管跨应力响应的期望穿阈率,进而确定总体疲劳失效可靠度。通过实例分析了跨长、设计寿命、初始裂纹长度、断裂韧性、裂纹扩展参数等对可靠度的影响,疲劳可靠度变化曲线可以对海底管道的设计提供参考。

Wave-Induced Fatigue Reliability Study of Submarine Pipeline Span by First Passage Failure Approach

Fatigue reliability of submarine pipeline span under the wave is study based on first passage theory of stochastic vibration and reliability theory.Failure criteria are established by fracture mechanics principle.The fatigue failure of pipeline span is coined as a first passage problem.The long-term stochastic sea case is treated as several discrete short-term cases which are described by Rayleigh distribution.Modal approach is used to derive the stress response spectrum of pipeline span under the short-ter...