坠物撞击下裸置海底管道凹陷损伤数值模拟研究

Numerical simulation on the dent damage of unburied submarine pipelines impacted by dropped objects

本文采用三维非线性动态有限元法分析了不同撞击能量下裸置海底管道受坠物撞击的凹坑损伤变化规律。首先通过与实验测试结果的对比验证了管道受坠物碰撞的有限元数值模型的可靠性,然后选取不同海床土体力学性质、管道沉陷深度、管道边界条件等参数对海底裸置管道坠物撞击损伤的影响进行了分析,最后将DNV规范及经验公式计算结果与有限元数值模拟结果进行了对比分析。结果表明:海床土体力学性质、管道沉陷深度和管道边界条件对管道的凹陷损伤程度具有显著影响,DNV规范及经验公式计算值偏大,结果偏于保守。

The three-dimensional nonlinear dynamic finite element method was used to analyze the dent damage law of unburied submarine pipelines impacted by different impact energies.Firstly,the reliability of the finite element numerical model of the pipeline impacted by dropped objects was verified by comparison with the experimental test results.Then,a parametric study was carried out to analyze the effects on the unburied pipeline impacted by dropped objects considering the factors such as subsoil mechanical properties,subsidence depth and boundary conditions of the pipeline.Finally,the results from the DNV specification and empirical formula calculation were compared with those from the finite element numerical simulation.It is shown that the degree of dent damage of the pipeline is significantly affected by subsoil mechanical properties,subsidence depth and boundary conditions of the pipeline.The calculated values of the DNV specification and empirical formula are larger than the numerical simulation results,which means the DNV specification is conservative.