Study On Shock Initiation Characteristics Of JO-9C Booster At Different Ambient Temperatures

The shock initiation characteristics of booster is closely related to its ambient temperature.When the booster is in low-temperature environment,its shock sensitivity may become insensitive.The transmission of detonation wave could not be normally completed in the explosive train,resulting in the reduction of its detonation transmission reliability.While in high-temperature environment,its shock sensitivity will become higher.The booster may be caused to ignite,burn or even detonation before normal use,resulting in the reduction of its detonation transmission safety.Due to the different transportation,storage and use conditions,the actual ambient temperature of booster is often different from that of ordinary temperature,so the shock response process and initiation mechanism of booster under different temperature become the important research contents of the reliability and safety of booster.Therefore,it is important to study the shock response law and initiation mechanism of booster at typical ambient temperature for weapon safety evaluation.In order to study the shock initiation performance of JO-9C at different temperatures,the small scale gap test（SSGT）of JO-9C at 25℃was carried out first.When it was used for SSGT at other temperatures,the test results were compared and analyzed.The critical thickness of JO-9C was obtained by using different thickness of polymethyl methacrylate（PMMA）at 25℃.Secondly,the SSGT of JO-9C was accomplished at the temperature of-25℃,88℃and 117℃.According to the test results,the temperature calibration experiment of JO-9C is designed to improve the accuracy of the internal temperature of JO-9C under different temperature,and then the SSGT under different temperature is completed.The critical thickness of JO-9C is obtained by observing the fragmentation degree of the confined steel shell,the explosive residue inside the shell and measuring the pit depth of the identification block.Finally,the influence mechanism of different temperature on the initiation performance of booster is discussed.In order to study the shock initiation process of JO-9C at different temperature and the influence of different temperature on its shock sensitivity,the numerical simulation of SSGT for JO-9C at different temperature was conducted.At first,the AUTODYN software is used to model and calculate the SSGT under the temperature of 25℃,and the parameters of the model are fine adjusted according to the test results of the SSGT under 25℃.The state equation parameters of JO-9C at 25℃and the propagation of shock wave pressure in RDX,PMMA and JO-9C are obtained.The critical initiation pressure of JO-9C at 25℃is also calculated.Secondly,based on the state equation parameters of JO-9C at 25℃and the adjustment rules of state equation parameters of JO-9C at different temperatures,the unreacted explosive equation parameter B and the ignition and growth reaction rate equation parameter G₁ of JO-9C are changed regularly,so that the simulation results at-25℃,88℃and 117℃are consistent with the test results.The parameters of the state equation of JO-9C at-25℃,88℃and 117℃are obtained.By analyzing the simulation process,the propagation process of shock wave pressure in PMMA and JO-9C and the critical initiation pressure of JO-9C at different temperatures are obtained.By comparing the simulation results of SSGT at different temperatures,the relationships were given between the model parameters and temperature.It is of great practical significance and application value to study the response characteristics of booster under shock wave at different ambient temperatures by the method of SSGT and numerical simulation,so as to reduce the occurrence of accidental explosion accidents caused by the influence of ambient temperature on the detonation performance of booster in ammunition system,as well as reduce casualties,equipment damage and property loss.