Study On Noise And Vibration Characteristics Of Explosion In Explosion Vessel Under Negative Pressure

In order to study the vibration and noise characteristics caused by the explosion in the explosive container under negative pressure,the self-designed and manufactured small vacuum explosion tank and 5 kg TNT equivalent spherical explosive container were studied in this paper.Explosion experiments in negative pressure environment were carried out in small vacuum explosion tank and 5 kg TNT equivalent explosion vessel.With the help of NUBOX 8016 blasting vibration tester,LeCroy oscilloscope,SZ4A noise vibration tester,acceleration sensor and other instruments,the vibration and noise parameters generated by the explosion were tested.The main contents and results of this paper are as follows:1)The peak velocity of cylinder vibration decreases with the increase of vacuum degree;As can be seen from the vibration data of the small vacuum explosion tank,the maximum vibration velocity of the cylinder is 14.26 cm/s under normal pressure and 4.323 cm/s under-99 kPa.The vibration velocity of close to vacuum is attenuated by about 70%compared with that of normal pressure.As can be seen from the vibration data of 5 kg TNT equivalent explosive container,when the experimental charge is 300 g emulsion explosive,when the pressure in the container decreases from normal pressure to-80 kPa,the vibration peak velocity decreases by about 25%.2)With the increase of the negative pressure inside the explosion container,the air in the container becomes thin and the explosion energy decreases significantly.It can be seen that the parameters of shock amplitude and duration show a downward trend.3)It can be seen from the negative pressure experiments in a small vacuum explosion tank and a 5 kg TNT equivalent explosion vessel that the improvement of vacuum degree is helpful to reduce the explosion noise.4)There are about 10 imf components decomposed by EMD of vibration signal of small vacuum explosion tank,among which the first three are mainly imf components with high contribution rate.Under normal pressure,the highest contribution rate is imf₂,which accounting for more than 60%;Under the condition of negative pressure,the highest contribution rate was imf₁,which accounting for more than 40%;There are about 18 IMF components in the EMD decomposition of vibration signal of 5 kg TNT equivalent explosive vessel,among which the high contribution imf components are mainly in the first seven,and the higher contribution imf components are imf₄,imf₅ and imf6,they accounting for at least 20%and the highest 40%;5)The vibration signals of the small vacuum explosion tank were processed by Hilbert-Huang transform.The higher part of the main frequency energy was mainly between 0?0.02 s,and the frequency was mainly concentrated in the lower part of 0?200 Hz,and the energy gradually decreased with the time passing.With the increase of vacuum,the frequency distribution diffuses from the low frequency part to the high frequency part;The vibration signal of 5 kg TNT equivalent explosive vessel is transformed by Hilbert-Huang transform,the frequency of vibration signal is mainly distributed in the low-frequency part of 0?500 Hz,500?1000 Hz is relatively weak,the higher the frequency of the parts above 1000 Hz,the weaker the energy;As time goes on,the energy gradually decreases;With the increase of vacuum degree,the frequency distribution decreases from 0?1.6 s to 0?0.8 s.Explosive vibration,noise and other harmful effects have a great impact on the surrounding environment,leading to explosive processing operations are mostly carried out in remote mountainous areas.Explosive welding under vacuum condition is an effective method to reduce the harmful effects such as vibration and noise.Reducing this kind of harmful effect is expected to make explosive processing enterprises urbanization,factory,reduce transportation costs and improve work efficiency.Simulation of explosive detonation mechanism,explosive performance and shock wave propagation law under high altitude environment can provide theoretical reference for ammunition damage effect and damage parameters under high altitude environment,so as to achieve the purpose of damage performance optimization and accurate target attack.Therefore,it is of great significance to probe into different vacuum degrees in explosion experiments.Figure[31]Table[15]Reference[106]...