Investigation On Some Key Measuring Technologies Of Fragment Warhead Power Field

There is a huge release of energy during the explosion process of prefabricated fragments.At the same time,there are strong blaste waves,high temperature and high pressure detonation products and target damage.Therefore,research on the key technology of warhead damage power field can provide important support for warhead power evaluation.The main damage elements for warhead are fragment and blast wave.It mainly depends on the kinetic energy of fragments to breakdown and damage target.Since the killing effect of fragment is closely related to its velocity,the shape and the quality when fragments strike the target,so the fragment velocity is a very important tactical assessment index.However,the transient characteristics of the warhead explosive field and parasitic effects of interference,put forward higher requirements on the attenuation of fragment velocity.The typical characterization parameters of blast wave are overpressure value,positive pressure and impulse duration.But due to the interference of explosive field high temperature and high pressure,strong fire and other factors,the measured pressure curve is distorted and difficult to interpret.Therefore,it is necessary to improve the measuring systems of blast wave,and carry out a series of research on calculating specific impulse,spectrum,and energy spectrum.This paper mainly adopts the theory analysis,experiment and numerical simulation,and focuses on two main damage elements of the large equivalent warhead explosion.The research on measuring method and characteristic analysis method of fragment and blast waveand are carried out.The main research contents and conclusions are as follows:(1)The paper carries out a detailed analysis of measuring systems and existing problems on fragment velocity and blast wave pressure.A fragment velocity test system,an electric blast wavepressure test system and the evaluation system of the effect of target based on blast wavepressure are established.The measuring system of fragment velocity is mainly composed of some light screens and data acquisition system.Then the fragment velocity attenuation model is established through data analysis.Blast wave pressure measuring system consists of sensors,signal conditioning module and the data acquisition system.The peak pressure,positive pressure time,specific impulse,spectrum and energy spectrum is obtained by analyzing the tested curve.The paper put forward an evaluation method based on effect of target impact and set up the test system,evaluating the damage efficiency of the pressure of blast wave by the maximum deflection effect the target.(2)It establishes the cylinder velocity attenuation model of the spherical fragment and cube fragment and an equation to predict velocity at a point.A high speed loading device design fragment is firstly improved in this paper.Through subsection experiment,the speed time and displacement value of three kinds of fragments are obtained.The attenuation coefficient is then obtained by data fitting of typical fragment velocity.The results show that the attenuation coefficient of spherical fragments with three speed segments remaining stable and the spherical fragment velocity attenuation model is reliable.The prediction of initial velocity and velocity at a point equation about cylinder and cubical fragments based on cxS-Ma provides a theoretical basis for calculating the lethal radius of warhead fragments and lethal field.(3)Based on the results of theoretical analysis and simulation,a kind of sensor mounting device which can restrain the parasitic effect is designed.The sources of two kinds of important parasitic effects of high mechanical impact and thermal shock are analyzed.The mathematical model of the sensor system without parasitic effect suppression and with parasitic effect suppression is established.The effect of the device is verified by simulation and field test.The results show that the sensor test data with the parasitic effect suppression device can effectively suppress the vibration signal in both amplitude and frequency,which provides a reliable data support for the analysis of blast wave pressure in the later research.(4)The spectrum analysis and energy spectrum analysis of blast wavepressure are studied,improving the accuracy and precision of signal decomposition by improving EMD/HHT.A signal processing software for blast wave pressure is designed.The results show that for the same kind of explosives,low-frequency energy is greater than the high frequency energy value and the damage efficiency of target is better.At the same time,along with the increase of distance,the proportion of low frequency energy is increasing and high frequency energy proportion is decreasing gradually.The error of the integral method to calculate the impact impulse is less than 4.79%,which is better than the maximum error of the commonly used numerical integration method 18.644%.(5)A new method for evaluating the pressure of blast wavebased on the target is proposed,and the deformation deflection model of the target is established according to the principle of dimensional analysis and similarity.Using ANSYS/LS-DYNA,the numerical simulation of different materials,different shapes and different sizes under the effect of target deformation response are calculated respectively.According to the calculation results,the material of effect target is 2A12 aluminum alloy,and the size is?300×2mm.Three kinds of warhead explosion experiment of 100kg,60kg,20kg is carried.The results show that the experimental results of the maximum deflection of the vertical target and the flat target are respectively 3.59%and3.33%.And it is proved that the model is effective.