Characteristics and Mechanism of Slow Cook-off of Composite Explosive Charges

In order to study the response law of composite charges with different structures in the process of slow cook-off, the cook-off bombs filled with $\varnothing $19 mm single charges of explosives JH-2 and JHB and $\varnothing $30 mm composite charges were designed. The temperature-time curves of single charges at 1 and 2 ℃·min⁻¹and composite charges at 1 ℃·min⁻¹ were obtained in tests, and combined with the numerical simulation to further analyzed the temperature field inside the bomb. The research results show that in the case of a single charge, the low-sensitive explosive can significantly reduce the response level of the bomb under thermal stimulation; while in the case of a composite charge, the response point of the bomb is located at the annular region of the outer low-sensitive charge near the shell. The response temperature increases with the increase of the high-energetic charge’s diameter, and the response level increases with the increase of the outer low-sensitive charge’s thickness. The heat transfer in the bomb is retarded due to the contact thermal resistance between the contact surface of composite charges, thus the inner high-energetic cylinder is rarely involved in the reaction.