Burning Damage Characteristics of Polyurea Layer under Transient Temperature Field by Near⁃field Explosion

In order to study the burning damage characteristics of polyurea anti‐blast layer under the action of explosion transient temperature field，experimental tests were carried out for the polyurea coated capsule liquid‐filled container with different thickness（1 mm，4 mm and 6 mm）under the condition of close‐in explosion. The macro‐micro damage characteristics of the polyurea layer after explosion transient high temperature burning were obtained by explosion experiment，and the burning mechanism of the explosion temperature field on polyurea was analyzed using the colorimetric temperature technology and the numerical simulation method. The results showed a maximum explosion temperature of passivated hexogen（RDX）of about 3792 K under the described experimental conditions，which was higher than the initial decomposition temperature of the polyurea material （231.2 ℃）. The burning phenomenon occurred on the surface layer of the polyurea. When the thin layer between the surface layer and the internal hole was broken by penetration，the detonation product entered the internal hole of the material，thus resulting in a significant increase in the burning depth of the polyurea and the formation of a spotted burning outer layer. The ignition degree of polyurea was positively correlated with the density of detonation products and the propagation velocity of detonation products along the thickness of the polyurea layer. Besides，ignition occurred when the mass per unit area of detonation products acting on the polyurea layer reached 0.0195 g·cm-2. Heat conduction was the main reason for the thermal decomposition of polyurea. Overall，the research method and results could provide reference for the engineering protection evaluation of polyurea and the modification of anti‐blast polyurea. © 2023 Institute of Chemical Materials, China Academy of Engineering Physics. All rights reserved.