Research on Impact Initiation of Unconfined and Confined Explosives by Explosively Formed Projectile

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Abstract

To investigate the shock initiation of explosives by Explosively Formed Projectile (EFP), a numerical simulation study was conducted using the Autodyn finite element software, focusing on the shock initiation behavior of EFP against both unconfined and confined explosives. This study revealed the critical initiation cover thickness for both types of explosives. Additionally, an analysis was performed to explore the initiation mechanisms of EFP on explosives beneath various cover plates. Furthermore, an engineering model for the critical initiation threshold of EFP initiating explosive was established. Finally, experimental research on EFP initiating explosive was carried out to validate the simulation results and engineering model. The simulation results indicate that as the cover plate thickness increases, the initiation mechanism transitions from explosive initiation by shockwaves generated by EFP impact to explosive initiation by the remaining EFP after it penetrates the cover plate. By fitting the simulation results, the equivalent diameter calculation method for annular cross-section impact initiation explosives was derived. Based on simulation results and the A-T penetration model, an engineering model for the critical initiation threshold of EFP initiating explosives was developed. Experimental data demonstrated that this engineering model could predict the critical initiation cover thickness for EFP initiating explosive.

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Published

10-12-2025

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Original Article