Calculation of Air Shock Wave Pressure on the Back of an Explosive Flying Plate Colliding with a Thick Steel Plate
When the explosive flying plate collided with the thick steel plate, Zhou Tingqing, Wang Fengying, Liu Tiansheng 21. Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026; 2. Department of Environmental and Safety Engineering, North China Institute of Technology, Taiyuan 030051, the free and rapid change of the plate was numerically calculated. The interface between the steel plate and the air is also used to perform spherical symmetry numerical analysis of the shock wave propagation in the air behind the steel plate. The results obtained are in good agreement with the actual measured values. Introduction The stress wave in the thick steel plate under the action of the explosive plate driven by the explosive explosion The calculation and propagation of the propagation and destruction of the steel plate are obtained, and it is well handled 1. However, the occurrence and development of the shock wave in the air on the back of the coupling between the steel plate and the air medium cannot be solved well. In order to solve this problem, this paper uses the dimensional axisymmetric dynamic finite element numerical analysis method to numerically calculate the movement of the free surface of the thick steel plate under the action of the explosive plate driven by the explosive plate, and uses the conditions of the equal speed of the thick steel plate and the air interface to the back of the steel plate. The dimensional spherical symmetry numerical analysis of the shock wave propagation in the air was carried out, and the distribution of the shock wave overpressure behind the thick steel plate with the distance under the action of the flying plate driven by the explosive explosion was obtained. This result is in good agreement with the actual measurement.
1 Model hypothetical explosive flying plate steel plate; acridine air medium. The charge of this question is a flat shape, the thickness of the charge is the thinning explosive flying plate, the thickness of the thick steel plate is Dan.
It is assumed that because the thickness of the explosive is very large, the detonation duration is very short, and it is treated as instantaneous adiabatic detonation in the calculation process; 1 Explosion plate sequence steel plate due to the thin explosion explosive plate, the velocity when colliding with the thick steel plate is high, the collision The process can be regarded as an inelastic collision. The density of the armor and the air medium is very different. When calculating the transmission process of the stress wave in the thick steel plate, the collision of the thin plate is assumed to be surface contact, which lasts very short, and the plastic deformation of the thick steel plate Very small, there are only slight indentations on the collision surface, so the armor is regarded as an elastic medium when calculating the stress transmission in the thick steel plate.
2 The determination of the speed of the thin plate after the explosive explodes is based on the principle of adiabatic drying time. The impulse to maintain the explosion is 1 velocity, and the heart = the uneven distribution coefficient of the explosive explosion 01 is the explosion heat of the explosive. Take 01396. Let the mass of the thin plate be that the average speed of the thin plate is conserved according to the movement. The motion of the thin plate should be equal to the explosive impulse of the explosive. The speed of the thin plate is 3 The collision pressure and action time on the thick steel plate If the average impact impact per unit area 1 is taken, the average pressure of the nail on the thick steel plate is the average pressure per unit area of ​​the thick steel plate. It can also be written as the speed calculation of the free surface of the thick steel plate. The block diameter taken from the thick steel plate is a numerical analysis method of the steel armor history collision finite element analysis. If the thickness of the free surface of the thick steel plate is calculated by calculating the air shock wave pressure of 0.0051 at any time when the sealing material is about 2 pieces of sealing material and the crotch steel plate is taken. The calculation result 3.
Speed-time curve of free surface of steel plate.
5 Calculation of the shock wave overpressure in the air on the back of the thick steel plate From the speed-time curve of the free surface of the thick steel plate, the speed changes with time are continuous, and the wave propagation can be regarded as being transmitted according to the local acoustic wave speed, according to the interface Velocity conditions, the local sound velocity is 2 wide lag, you have a characteristic relationship across the incident right traveling wave. Bring the 9 type into the 8 type to get the thick steel plate incident on the air interface. The pressure is calculated by the 10 type. The air behind the thick steel plate can be calculated. At mid 0.005, the shock pressure initial pressure time history curve in the air behind the thick steel plate.
At 45, the pressure distribution on the air interface of the thick steel plate. From the pressure distribution form, the attenuation law of the shock wave in the air with distance can be regarded as an example of the case of an infinite medium mesothelium, the calculation result is 6.
6 The comparison value between the calculation result and the experiment is 1.2312 atmospheres. When the shock wave moves to 0.1 claws away from the steel plate, the peak value of overpressure is only, and the peak value of 8 overpressure in Class 6 is reduced by nearly 20 times. After the shock wave overpressure attenuation is very slow, when the shock wave moves to the steel plate 5, 1 when the peak value of the overpressure is 2, only reduced by 0.01.
Varying experimental curve. It can be seen from the curve that the peak value of the measured shock wave overpressure is only 0.013 higher than the calculated value. This error is related to the assumption of the calculation model. Obviously, the calculation results according to the numerical calculation model proposed in this paper are in good agreement with the experiment.
Refer to Zhou Gongong. Liu Xiaomin. Numerical Analysis of Stress Wave Amplifiers Dimensional Science and Mechanics 9 Zeng 69797 I2 as a numerical analysis of the stress of the arc co-community called arrogant stress wave propagating in the intercept bar 1 Journal of Aeronautics, 1998, 19
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