Efficient Cutting of Submarine Pipelines by Linear-Shaped Charge

Directional explosive cutting method has been applied to the cutting, maintenance and even destruction of submarine pipelines because of the high cutting speed and low risk to adjacent components. This paper develops a three-dimensional numerical model for the damage effects on the pipe induced by the Linear-Shaped Charge (LSC). The explosive is 50 kg TNT. The internal diameter of the pipe is 871 mm, and the thickness of the steel wall is 34 mm. The standoff distance is set to 1.0 times the height of the LSC and an air cavity is added in front of the liner for better jet formation effect. The pipe is filled with air, and the bottom of the pipeline is anchored to the seabed. Due to the symmetry of the numerical model, a quarter of the numerical model is established in order to improve the calculating efficiency. The FSI (Fluid-Structure Interaction) is taken into consideration. Based on structured-arbitrary Lagrange Euler (S-ALE) method, the damage process of the pipeline under the coupling load of the jet penetration, hydrostatic pressure, shock wave and bubble is investigated. According to the numerical simulation results, the pipe is immediately destroyed under the combined effect of the load. The results indicate that it is possible to effectively cut the pipelines by using a linear-shaped charge technique.