On the accuracy of CEL blast simulations: validation and application

The coupled Eulerian–Lagrangian (CEL) method has shown good capability to simulate large deformation behavior in the blast response of complex structural and multi-physics systems. However, the published literature has not addressed blast wave characteristics in free open-air space or directly compared the results of such studies with experiments. In this study, the authors performed three-dimensional (3-D) non-linear finite element (FE) analysis of CEL model utilizing ABAQUS/Explicit finite element software to estimate blast wave parameters, peak overpressure (P_so), time of arrival (t_a), positive phase duration (\({t}_{o}^{+}\)), and blast shock wave front velocity (U) in comparison to empirical Kingery–Bulmash free air-blast predictions and recently published small-scale blast field test results. The height of spherical and cubical TNT charges (HOE) is 5.0-m inside a Eulerain domain (ED). The air and trinitrotoluene (TNT) charge are modeled using (C3D8R) continuum solid elements and the Eulerian domain is modeled as a volume element using (EC3D8R). The CEL model results show good agreement with Kingery–Bulmash predictions and experimental data for incident peak-overpressure, time of arrival, and blast shock wave velocity of considered scaled distances. However, the CEL model outcomes of positive phase duration showed a difference from Kingery–Bulmash model as high as 55% due to secondary shock waves moving inward and reflected toward the source of burst. Despite the extensive validation of the Kingery–Bulmash empirical model, direct measurements in open-space indicate that incorporating blast wave propagation phenomena is critical in different explosion scenarios, especially when reflection phenomena are probable. As a practical model of the CEL model, the blast response and damage evolution of a X70 steel pipe subjected to contact pipe bomb charge is investigated. This grade of steel pipe is a reliable material and used in oil and gas transmission pipelines. The post-damage simulation showed wall thickness has significant contribution to improve the response of the pipe and blast-post damage evolution. This study aims to highlight the efficiency of coupled Eulerian–Lagrangian (CEL) technique to simulate blast for a better understanding of wave propagation in free space and wave-structure interaction phenomena when blast waves interact with structures.