Numerical model for unstable ductile crack propagation and arrest in pipelines using finite difference method

• A numerical model to predict unstable ductile crack propagation/arrest is proposed.
• The model is based on finite difference method.
• Gas decompression, pipe deformation and crack propagation are formulated.
• Effect of soil backfill depth is formulated in the model.
• The model predicts experimental results reasonably well.

Prevention of unstable ductile crack propagation has been a great issue in pipeline industry. For appropriate pipe design, the authors developed a numerical model to predict unstable ductile crack propagation/arrest using finite difference method. The features of the model are as follows: (1) pipe deformation and gas decompression are formulated based on one-dimensional partial differential equations; (2) the interaction among pipe deformation, gas decompression and crack propagation is considered; (3) soil backfill effect, which constrains pipe deformation, is considered as added density. In this paper, the model is described in detail, and applied to full-scale natural gas pipe burst tests.