A Validation Study on Dynamic Response and Failure Analysis of Large Unconfined Pipes Under Localized Blast Loading Using an Explicit Dynamic Approach

This study utilized an explicit dynamic approach to analyze the dynamic behavior of large-diameter pipes subjected to localized blast loading. The objective of the validation study was to investigate the effects of the explosion's blast force on the dynamic response and material behaviors in large-diameter pipes. The existing experimental data were benchmarked with the numerical results to assess the prediction accuracy. The crucial factors include the amount of the explosive mass (0.2–5.0 kg), the contact regions, and the wall thickness of the pipe (1.46 cm and 2.62 cm). As a result, the contact area significantly influenced the deformation range in each case, ranging from 50 to 400 cm2. The amount of explosive energy was crucial in determining the material response. For instance, deformations like pitting and spallation were found in the case when testing with less than 1.4 kg of TNT, whereas complete tearing in the central area was found in the case for higher explosive mass. With modest explosive mass, the pipe material underwent inelastic deformation. However, the material became vulnerable to adiabatic shearing failure when the explosive energy exceeded 1.4 kg in penetrating the 2.62 cm-thick walls. The difference between the simulations and experimental deformation (1.46-mm-thickness) was average at 8.5%, which presents an attractive tool. Therefore, this explicitdynamic tool will be used in subsequent research to study the responses of structural building systems to occasional explosion scenarios and capture the explosion fragments.