Experimental and numerical studies on the deformation and tearing of X70 pipelines subjected to localized blast loading

• Four failure modes of large diameter X70 pipelines are observed and studied during the experiments.
• Post-failure motion of the pipeline is studied using numerical and experimental methods.

The dynamic response of X70 grade steel pipeline under localized blast loading is studied by experimental and numerical investigations. The steel pipelines with large diameter and high grade are concerned in the paper. The influences of the explosive mass, contact area and wall thickness on the deformation/failure mechanisms of the X70 pipelines were investigated. The post-failure motion of the fragment was also observed during the experiment. Four different failure modes were observed during the experiment namely Mode I, Mode II, Mode IIIa and Mode IIIb. The features of each mode are analyzed concretely. Results revealed that the deflection and damage level of pipeline increased with the increase of explosive mass and contact area. The wall thickness plays an important role on the damage and post-failure motion. Numerical simulations based on the experimental results were conducted. The damage process, midpoint deflection, pressure distribution, energy changes and the post-failure fragment velocities were analyzed. The results of numerical simulations show good correlation with the experiments