A forensic engineering technique for analysis of an explosion incident

This article investigates the validity of current forensic practices to analyze an explosion event. The purpose of this study is to use forensic engineering techniques with the integrated models for the simulation of blast fragments and blast pressure to determine an explosive weight used in a bombing incident and later predict a lethal radius caused by blast pressure and a lethal zone caused by fragment impact. The real explosion incident at the Erawan shrine in central Bangkok on August 17, 2015, is selected as a case study. By comparing the structural damage at the blast site to the one obtained from finite element (FE) analyses, an estimated bare charge weight of TNT used in the incident can be obtained. It was found that an estimated bare charge of 3 kg TNT equivalent could have been used for the bomb. To confirm the validity of the calculated explosive weight, a combined lethal zone from blast pressure and scattered fragments was analyzed. Human damage due to the blast pressure is analyzed based on Bowen's lethality curves. The lethality zone from expelled fragments is drawn based on a 50% probability of lethality, which considers the hit density and kinetic energy of the fragment. The analyzed lethal zone agrees reasonably well with the actual observed human damage level. The proposed forensic engineering technique offers the potential for enhancing management and policies in homeland security, contributing to a safer community.