含初始缺陷管中管侧向屈曲过程中的动态效应研究

Study of Dynamic Effect on Lateral Buckling of Pipe-in-Pipe System with Initial Imperfections

随着海洋油气开采深度的逐渐增加,深海石油管道在高温高压运输过程中会存在整体热屈曲现象,而热屈曲的过程中可能会存在动力效应.管中管广泛应用于深海油气输送结构,但是相关整体屈曲试验及动力效应研究很少.本文以初始缺陷波长及幅值作为变参数,对含有初始缺陷的双层管道的试验方法进行了详细介绍,并通过3组试验,对整体热屈曲试验过程中产生的动力效应现象及原因进行了分析,发现初始缺陷波长对整体屈曲过程中的动态效应起到关键作用.基于此,采用ABAQUS隐士动力分析方法建立了双层管道整体屈曲有限元分析模型,并与试验结果进行了对比,验证了模型的准确性.进而分析了管道直径大小、初始缺陷长度以及管土作用对管道屈曲过程中动态效应的产生及影响变化规律,发现了各个因素与管道中点屈曲临界力、侧向弹出速度、侧向位移以及整体动能之间的关系,通过对比分析,找到了径厚比最佳临界点以及缺陷波长与管道长度比值的临界控制点,发现管土作用对整体屈曲动态效应有显著影响,并对产生机理进行了分析,研究成果对深海油气输送双层管道结构的设计及铺设有一定的指导意义.

With the gradual increase of offshore oil and gas exploitation depth , there will be global thermal buckling in deep sea oil pipelines during high temperature and high pressure transportation , and there may be dynamic effects in the process of thermal buckling of the pipe-in-pipe ( PIP ) system. PIP systems are widely used in deep-sea oil and gas transmission structures , but the related experiments and dynamic effects on global buckling are seldom studied. Taking the initial imperfection wavelength and amplitude as variable parameters , this paper introduces the experimental method of PIP system with initial imperfection in detail. Through three groups of experiments , the phenomena and cause of dynamic effect in the global thermal buckling experiments are analyzed , and the dynamic effect of initial imperfection wavelength which play a key role on the global buckling process is found. Based on this , the ABAQUS hermit dynamic analysis method is used to establish the finite element analysis models of the global buckling of PIP system , and the accuracy of the models are verified by comparing with the experimental results. Then the influence of pipe diameter , initial imperfection and pipe-soil interaction on the dynamic effect of pipeline buckling is analyzed. The relationships between each factor and critical buckling force , lateral ejection velocity , lateral displacement and overall kinetic energy of pipeline are found. Through comparative analysis , the critical point of the ratio of diameter to thickness and the critical point of the ratio of imperfection wavelength to pipe length are found. And the result of the pipe-soil interaction has a significant influence on the global buckling dynamic effect and the mechanism is analyzed. At last , the research results have a certain guiding significance for the design and laying of deep-sea oil and gas transmission PIP system.