Research On Waveform-broadening Of Mechanical Overload Simulation Test On Air Gun

As the initiation device in ammunition system,the explosive initiator will be overloaded by millisecond-class impact during penetrating targets.However,the current methods are not capable of conducting the mechanical overload simulation test with ms-class pulse width.To address the problem of insufficient overload pulse width,the waveform broadening of the test based on the existing air gun devices was studied in this research.The main contents are as follows:(1)Aiming at the problem that the original air gun device were not able to obtain the acceleration waveform of overload,an air gun mitigation apparatus was designed.The mechanical parts of the apparatus were designed in detail.Each component was connected by threads,which meets the requirement of disassembly of the apparatus.The design and construction of data acquisition system were completed,which can get the real-time acquisition of acceleration signal.The mechanical properties of air gun mitigation apparatus were simulated by LS-DYNA software.The results showed that,without any protective support,the air gun mitigation apparatus could only withstand the impact of bullet with velocity of 3.56 m/s without plastic deformation and 180m/s more after.The mathematical model of protection process was established so as to theoretically explain the feasibility of using soft materials to improve the impact resistance of the apparatus.Rubber as a type of soft material has been verified to show good performance of protection.(2)In order to obtain the accurate acceleration waveform,four different structures of sensor container were designed.Combining numerical simulation with experiment,the typical acceleration waveforms of the structures were obtained.The optimized sensor container structure was Non-sleeve sensor container with aluminum mass block.(3)Based on the designed mitigation apparatus,the influences of conductive rubber,industrial felt and open cell aluminum foam on acceleration characteristic spectrum of overload were studied.The extraction method of acceleration waveform eigenvalue(pulse width and peak value)was developed by waveform analysis technology.The results showed that under the condition of invariable mitigation material,the pulse width increased with the increase of thickness,and the uptrend was more obvious with the decrease of diameter.Open cell aluminum foam owned the most significant effect on waveform broadening,which was able to achieve the overload pulse width over 2ms.