海底管线管跨段模糊动力可靠性分析

Analysis on Fuzzy Dynamic Reliability of Submarine Pipeline Span

当海底管线受到复杂的环境载荷作用时,有必要对其动力响应和可靠性进行分析。首先,对海流和海浪作用下管跨产生涡激振动的机理进行了分析,建立了管跨在横向涡激振动下的力学模型,并应用振动理论得出振动微分方程,采用Galarkin方法求解出固有频率和动力响应规律。然后根据首超失效准则、疲劳失效准则和混合失效准则这三种模糊失效准则给出相应的模糊动力可靠性计算公式。最后给出具体算例验证了建模的可行性。从管跨的可靠性分析中看出,由海浪和海流引起的涡激振动是破坏管跨的主要因素之一。给出的管跨模型忽略了管跨端部土壤支撑的复杂性和地震载荷的作用,需要进一步做实验来探讨。

When submarine pipelines are subject to complex condition loads, it is indispensable to analyze their dynamic response and reliability. Firstly, under the effect of ocean wave and current, the mechanism of vortex-induced vibration generated by pipeline span was analyzed, and the mechanic model of span was found in transverse vortex-induced vibration. The vibration differential equation of pipeline span was obtained through applying vibration theory. The inherent frequency and dynamic response rule were solved by adopting Galarkin method. Then, according to the three kinds of fuzzy failure rules, that is, the first excess over allowed value, fatigue failure and mixed failure, the corresponding computation formula of fuzzy dynamic reliability was given. Finally, an application example was provided to testify its feasibility. From the reliability analysis of span, vortex - induced vibration resulting from ocean wave and current is one of primary destroy factors. The span model ignores complexities of span ends＇ soil supporting and seismic load effects, it needs doing experiments to further discussion.