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采用非线性动态有限元法模拟了坠物撞击海底管道的过程。以Ramberg-Osgood模型模拟海床,同时考虑混凝土涂层拉、压不同的非线性特性,并利用罚函数法处理坠物、海床与管道之间的相互作用。分析了物体形状、撞击角度、摩擦、内压、混凝土厚度、埋深及悬空长度对管道撞击塑性变形的影响。结果表明:坠物以尖端撞击管道时,凹痕深度较大,但凹痕范围相对较小;90°撞击时对管道的塑性变形影响最大,摩擦系数影响较小;内压增加了管道的应力,但减小了凹痕深度;混凝土层对重量较大坠物的防护作用较弱;埋深超过1m能有效防止管道受撞击破坏;悬跨减小了管道凹痕深度,但使管道更容易产生整体破坏。与现行规范计算结果相比,该文方法更加符合实际。
Nonlinear dynamic finite element method was used to simulate the impact of falling objects on submarine pipelines. The Ramberg-Osgood model is used to simulate the sea floor, taking into account different nonlinear characteristics of the concrete coating pull and pressure, and the penalty function method to deal with the interaction between the falling objects, the sea floor and the pipeline. The effects of object shape, impact angle, friction, internal pressure, concrete thickness, depth and suspended length on plastic deformation of pipeline were analyzed. The results show that when the falling object impacts the pipeline with the tip, the depth of the dent is larger, but the dent area is relatively smaller. When the impact is made at 90 °, the plastic deformation is most affected and the friction coefficient is less affected. The internal stress increases the stress of the pipeline , But reduce the depth of the dent; concrete layer on the weight of larger objects is weak protective effect; depth of more than 1m can effectively prevent the pipe from impact damage; suspension reduces the depth of the pipe dent, but to make the pipe easier The overall destruction. Compared with the current standard calculation results, this method is more realistic.