Abstract:To study the detonation performance of 2,4-dinitroanisole (DNAN) based aluminized explosives,the detonating explosive / LiF interface particle velocity and free surface velocity imparted to thin metal plates for aluminized explosives RBOL-2 (DNAN/HMX/Al/additives) and RMOE-2 (DNAN/HMX/NTO/Al/additives) were measured by a laser displacement interferometer system for any reflector (DISAR). The detonation wave parameters were obtained for these two explosives according to the interfacial particle velocity histories. The reaction zone lengths are (1.073±0.111) mm and (1.559±0.094) mm, the CJ pressures are (25.42±0.44) GPa and (20.99±0.15) GPa, and the Von-Neumann pressures are 27.69 GPa and 41.27 GPa for RBOL-2 and RMOE-2, respectively. The velocity histories of the metal plate show that the work capacity of RBOL-2 is better than that of RMOE-2. In addition, under the experimental conditions, the steady detonation status obtained by aluminized explosive is related to the initiation loading conditions and the loading pressure affects the work capacity of aluminized explosives. The greater the loading pressure, the stronger the work capacity. Under high loading pressure (21 GPa), the higher the loading pressure, the more aluminum particles react in the detonation reaction zone, and the stronger the detonation state of the aluminized explosive.

Abstract:In order to obtain the characteristics of electromagnetic radiation signals during the explosion of RDX and RDX-based aluminized explosives, the broadband antenna measurement system is utilized in explosion experiments. The experimental results show that the electromagnetic radiation signal of the RDX and RDX-based aluminized explosives has a significant delay compared with the detonation time. At 2 m distance, the field strength of the explosive electromagnetic radiation signal is 1.8-15.2 V·m^-1 and decreases with the increase in the explosive distance. When the aluminum content is from 0% to 20%, the field strength of the electromagnetic radiation signal generated by the explosion increases with the increase of aluminum content. When the aluminum content is from 20% to 30%, the field strength of the electromagnetic radiation signal generated by the explosion decreases as the aluminum content increases. The frequency of electromagnetic radiation signals generated by the explosion of RDX and RDX based aluminized explosives is mainly distributed within 500 MHz. The addition of aluminum changes the frequency component of the electromagnetic radiation signal, and the spectrum of the electromagnetic radiation signal of different aluminized explosives is different.

Abstract:To explore the design method of sealing structure which can meet the slow release requirements of warhead charge under slow cook-off condition，a small-sized cook-off bomb with adjustable connection strength and prefabricated area of pressure relief hole was designed. For octogen (HMX)-based aluminized explosive charge, the conditions of no more intense reaction occurs than combustion were obtained by experiments, including the strength threshold of shell and area threshold of pressure relief channel of cook-off bomb, etc. parameters. Based on this, a design method of two-stage sealing slow-release structure, which can satisfy the requirement of high connection strength and reliable pressure relief of the end cap, was proposed and the method was tested and verified in the cook-off bombs with kilogram charge. The results show that when two-stage sealing design for cook-off bomb is adopted, if the ratio of the area of the pressure relief channel to the charge cross section is not less than 30%, and the pressure of the gas product does not reach 96.5 MPa in the slow cook-off process, the pressure relief passage can be opened, which avoids the further growth of charge reaction, makes the combustion occur only and keeps the integrity of shell structure.

Abstract:To study the underwater explosion process of hexanitrohexaazaisowurtzitane (CL-20)-based polymer bonded explosives (PBXs) with and without aluminum powders, two kinds of explosives with aluminum contents of 0 and 15% were prepared.An underwater explosion experimental device was designed, and the images of pressure histories, bubble periods and bubble pulse of shock wave were obtained.The shock wave energy, bubble energy and total underwater explosion energy of two kinds of explosives were calculated The underwater explosion process was well-simulated by the AUTODYN software.Results show that when aluminum content increases from 0 to 15%, the total underwater explosion energy increases from 1.4 times TNT equivalent to 1.7 times TNT equivalent.In the process of bubble pulsation, the light is produced in the bubble of CL-20 based aluminized explosive when the time is from 49.5 ms to 49.8 ms.The peak pressure of aluminized explosives and nonaluminized explosives are 15.16 MPa and 15.51 MPa.The bubble of secondary pressure wave are 2.25 MPa and 2.35 MPa, 50.20 ms and 46.76 ms for the bubble periods.The maximum bubble radius are 67.87 cm and 60.27 cm.The simulation results of aluminized explosives and non-aluminized explosives overpressure are 14.90 MPa and 15.14 MPa.The bubble of secondary pressure wave are 2.16 MPa and 2.27 MPa, bubble period for 49.32 ms and 45.90 ms, 66.32 cm and 58.89 cm for the maximum bubble radius.The shock wave and bubble parameters obtained by calculation are in good agreement with experimental results.

Abstract:To obtain the change of thermal stress in the slow cook-off test of explosive charge, a set of thermal stress testing device was designed.The change curves of the thermal stress with temperature of octogen(HMX) based aluminized explosive charge under the closed confinement condition were obtained.Through adjusting the volume ratio of inert coating layer and charge, and changing the rising rate of thermal stress in the slow cook-off process, the critical response temperature of cook-off bomb and the intensity of response under three working conditions were researched.The difference of change rate of thermal stress, the whose process can be divided into six stages.Its influencing factors is thermal expansion, porosity decrease, HMX crystal transformation, slow decomposition of HMX, partial small molecule gas leakage, and accelerated decomposition of HMX in the order.When the temperature rises to 208 ℃, the thermal stress reaches 9.2 MPa and the charge is ignited immediately.Increasing the silicone rubber coating layer with greater thermal expansion on the charge surface of cook-off bomb, can make the growth rate of the thermal stress of charge accelerate and the critical ignition temperature of charge reduce, but the drastic degree of the response of charge does not change.

Abstract:To investigate the reaction process of aluminized explosives, the rapid reaction in RDX based aluminized explosive powder was stimulated by means of laser ablation, and the emission spectrum distribution in the reaction process was monitored in real time, and the transient temperature of the reaction region was calculated based on the molecular spectrum of AlO. Results show that there are obvious differences in the spectrum distribution and reaction behavior between the early and late stages of aluminized explosives. The early stage is mainly the plasma cooling and the dissipation process of RDX and air formed under la ser ablation.The emission spectrum from the O/H/N element is dominant in this stage, and its spectral line height is exponentially attenuated. The oxidation reaction of Al element is dominant in the late stage, and the reaction has a certain self-sustaining. The spectra of the corresponding intermediates AlO molecules have typical characteristics of persistent and non-monotonic changes. The trend of temperature change is closely related to the development trend of the whole reaction. The temperature of the severe reaction in the early stage is higher and decreases as the reaction continues to weaken.