| In order to provide reference for the application and development of insensitive munition and insensitive fuze of our country,it is necessary to study the method of improving fuze insensitivity.To achieve this goal,the military standard of domestic and foreign were compared from the aspect of the test method and evaluation criterion,the nosing process of desensitization explosive component was discussed,the initiation characteristic of small detonator was simulated,the heat response characteristic of fuze was studied.In order to improve the security and reliability of explosive materials,the military standard of China and United States were compared,including the type of explosive materials,test item of sensitivity,test methods and assessment criteria.The analysis results show that a large gap was existed between China and United States.For example,the type of explosive materials was not fully,the qualification tests of primary explosive and liquid propellant were not mention,test method was simple,assessment criterion was lack of objectivity and most criteria were rather qualitative.What's more,the qualification of low vulnerability explosive materials was not established,besides,the military standard was barely updated,the classification of test method was also less systematic and it is not easy to operate.Aimed at the low efficiency problem in traditional nosing process,the step by step method was applied by LS-DYNA simulation software,the typical cup material and size were simulated.It turned out that optimal nosing taper angle was approximately 80°,the cup could not be crushed and cup mouth expansion was not conspicuous in flat process later.Because of the cup nosing may lead to the charge density become larger,so the lead cup could not work as the input end.In order to decrease charge stress,lead cup should selecte lower strength materials,such as pure aluminum and copper.To provide reference for designation of insensitive fuze explosive train,the influence factors of small detonator initiation characteristic was studied by ANSYS/LS-DYNA,such as the different material,thickness and location of the baffle,the thickness of air layer,acceptor charge and constrain condition.The results show that the axial energy was the main function,the energy of bottom cap was red copper,soft steel and pure aluminum in turn.When the air layer thickness was 1 mm or 2 mm,the bottom cap should choose 0.2 mm priority,however when the air layer thickness was 4 mm,the bottom cap choose 0.4 mm was much better.The donor constrain condition had less influence relative to the acceptor for small detonator initiation characteristic,compared with aluminum alloy,the mild steel as the acceptor constrain material was much better.The more quantity of the charge,the better reliability of the initiation,the charge height also affect the optimum baffle thickness.To analyze the heat response characteristic of fuze under the fast cook-off and slow cook-off environment,the thermal reaction equation of explosive was described by user defined function,then it was imported into the Fluent software to simulate the cook-off process.The results show that under the slow cook-off environment,the ignition area appeared in the center circular of the explosive,with the temperature rate increase,the ignition time and ignition temperature decrease gradually.Fuze explosive charge type and charge density have a great influence on ignition time and ignition temperature,the ignition time along with the thickness increase,but it have nothing to do with the ignition temperature.Compared with four type coating,such as heating insulating coat(T-09),resin composite(carbon-phenol),heat-resistant ceramic tile(AETB-8)and heat-resistant(TGR-22),the best property of heat-resisting was AETB-8.The ignition temperature gradually decrease along with the thickness increase,but the ignition time become more longer. |
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