基于物理信息神经网络的断层作用下管道力学响应求解方法

Physics-Informed Neural Network Modeling of Pipeline Mechanical Response under Fault Effects

  • 摘要: 【目的】走滑断层引起的永久性地面位移是埋地油气管道的重要威胁,会导致局部形变并可能引发拉伸断裂或屈曲破坏,从而严重威胁管道结构安全。因此,准确预测走滑断层作用下的管道形变至关重要。【方法】提出了一种基于物理信息神经网络(Physics-Informed Neural Network,PINN)的断层位错作用下管道形变求解方法:搭建深度神经网络(Deep Neural Network, DNN),建立管道轴向位移与侧向位移在管道轴向空间坐标下的映射关系;基于虚功原理与冯·卡门应变,结合非线性土弹簧模型模拟管道与土壤的轴向及侧向非线性相互作用,并采用线性强化本构模型表征管材的非线性特征,从而构建走滑断层作用下管道形变的物理信息损失函数;结合断层作用下的管道力学特征,并通过迪利克雷边界条件建立边界条件损失函数,实现对受走滑断层作用管道形变的高精度预测。【结果】以某穿越断层区的1016 mm管道为例,选取有限元模型计算结果作为参考值,对比穿越角为30°、45°、60°、75°与90°,断层位移2.5 m多种工况下PINN模型同有限元计算结果,表明研究构建的模型同有限元计算结果具有较高的一致性,位移求解均方误差小于10-5,应变求解均方误差小于10-7。进一步扩展对比工况,对比国际多走滑断层作用下管道应变峰值求解方法,结果表明在不同的载荷条件下PINN模型同有限元方法求解应变峰值保持一致,平均相对误差仅为2.85%,显著优于其他应变峰值求解方法。【结论】该物理信息神经网络方法在计算效率、计算准确性方面有着显著的优势,可作为有限元计算方法替代方案,为断层作用下管道完整性提供了一种新方法。

     

    Abstract: Objective Permanent ground displacements caused by strike-slip faults pose a significant threat to buried oil and gas pipelines, potentially inducing local deformations that may lead to tensile rupture or buckling failure, thereby severely compromising pipeline structural safety. Accurate prediction of pipeline deformation under strike-slip fault action is therefore critical. Method A method for solving pipeline deformation under fault dislocation based on a Physics-Informed Neural Network (PINN) is proposed. A deep neural network (DNN) is constructed to establish the mapping between axial and lateral displacements of the pipeline along the axial spatial coordinates. Using the principle of virtual work and von Kármán strains, combined with a nonlinear soil spring model to simulate axial and lateral nonlinear interactions between the pipeline and surrounding soil, and a linear-hardening constitutive model to characterize the nonlinear behavior of the pipe material, a physics-informed loss function for pipeline deformation under strike-slip fault action is formulated. Coupled with pipeline mechanical characteristics under fault loading and Dirichlet boundary conditions to define the boundary loss function, this approach achieves high-precision prediction of pipeline deformation caused by strike-slip faults. Results Taking a 1016 mm-diameter pipeline crossing a fault zone as an example, finite element (FE) model results are used as reference. Comparisons for crossing angles of 30°, 45°, 60°, 75°, and 90° with a fault displacement of 2.5 m show that the PINN model closely matches the FE results, with mean squared errors of displacement below 10⁻⁵ and mean squared errors of strain below 10⁻⁷. Further comparisons across multiple fault conditions and international methods for predicting pipeline strain peaks under strike-slip faults indicate that the PINN model consistently predicts strain peaks in agreement with FE results, with an average relative error of only 2.85%, significantly outperforming other strain peak prediction methods. Conclusion The proposed PINN approach demonstrates significant advantages in computational efficiency and accuracy, serving as a viable alternative to FE analysis and providing a novel method for assessing pipeline integrity under fault action.

     

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