Pipeline crack propagation driving force calculation method and system

Abstract

The embodiment of the invention provides a pipeline crack propagation driving force calculation method and system. The method comprises the following steps: setting a corresponding elastic-plastic constitutive relation in a pre-built finite element model of a pipeline, and setting a tensile load and boundary conditions, wherein the boundary conditions comprise symmetric constraints and fixed constraints; meshing the finite element model, setting cracks and output parameters, performing finite element calculation, and extracting data after the finite element calculation; calculating to obtain afirst dimensionless coefficient through data obtained by finite element model simulation, wherein the first dimensionless coefficient depends on the crack size and the material performance and is a parameter related to the corrected limit load solution; and according to the first dimensionless coefficient, calculating the crack propagation driving force. The crack propagation driving force calculation method is simplified, the crack propagation driving force can be accurately calculated, fracture evaluation on the pipeline bearing plastic deformation is facilitated, and the accuracy of the evaluation result is improved.

Description

technical field [0001] The invention relates to the field of fracture mechanics, in particular to a method for calculating the driving force of pipeline crack extension. Background technique [0002] Pipelines are affected by factors such as complex geological conditions (such as discontinuous permafrost zones, earthquakes, landslides, and ground subsidence), installation construction, and actual operation during service, resulting in a nominal axial strain of 1-3%. Leaks or ruptures can occur if pipes cannot withstand the strains imposed by the environment during installation and service. This will not only cause huge economic losses, but also cause disastrous consequences such as environmental pollution and ecological damage, seriously affecting the smooth operation of society. To ensure the structural integrity of the pipeline, an Engineering Criticality Assessment (ECA) is required in accordance with international standards such as BS7910 and DNVGL-RP-F108 based on frac...

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Problems solved by technology

[0004] The accuracy of the above method greatly depends on the selection of the limit load solution, but when calculating the limit load solution of a specific material and component form, there are some problems that are not accurate enough (resulting in insufficient or too conservative fracture evaluation results), and the calculation of the limit load solution The physical meaning and theoretical basis of intermediate variables are not clear, and the influence of crack size and material properties on the ultimate load solution is not considered.

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