Research On Ground Explosion Wave Test Method For Near-Earth Explosion

The peak of shock wave overpressure is an important index of measuring ammunition damage effect.At present,the value of shock wave overpressure still cannot get through analytical method and numerical simulation method in this field.Therefore,it is the most important and effective way to obtain the parameter value of shock wave pressure by experimental measurement.However,it is found that the value of pressure has poor stability and consistency in the process of test,which reduces the reliability of measured data.Aiming at the difficulty of measuring the ground shock wave pressure generated by explosion near ground,research on the key techniques of ground shock wave pressure test method has been carried on.The coupling relationship between shock wave and test device has been simulated and analyzed.The effect of the complex ground environment on the test of shock wave pressure has been discussed.The influence law of the test device's tablet size,sensor's installation height and clearance,the close obstacle on the test result has been gotten.The verification experiment has been designed and the experimental result is a match with the simulation result.Besides,other common interference factors in the process of explosion shock wave pressure test have been analyzed and the corresponding suppression measures and compensation method have been put forward.The wireless storage and test device for measuring ground shock wave pressure has been designed and the experimental system has been set up.The high impedance charge output type piezoelectric pressure sensor has been chosen as the sensor for the shock wave measurement and the corresponding conditioning circuit has been designed,which realizes the conversion,filtering and amplification of the sensor output signal.The main control circuit has been designed based on STM32F103VCT6 chip and the storage module has been designed based on HY27UF081G2A type Nand Flash chip.In addition,USB communication interface circuit and trigger circuit have been designed and 4G wireless module,GPS module and power management module have been integrated.The software of slaver computer has been programmed based on C language to realize the triggering,data acquisition and storage and USB interface communication.The software of host computer has been programmed based on libusb to drive and realize USB communication.Besides,the interface of host computer has been programmed based on Labview to realize real-time control and display the slave computer.The performance test has been carried on respectively for the analog and digital module and PC software.The simulated experiments also have been conducted for the entire device.The host computer has realized the wireless setting of sampling parameters,real-time monitoring of the state and real-time acquisition of the shock wave signal characteristic parameters of the slave computer.The system also has realized the function of repeating acquisition.The error model of ground shock wave pressure test system has set up.The measurement uncertainty of each component has been calculated and the total measurement uncertainty of the device has been given.Because the ground shock wave pressure signal is mixed up with serious interference signal,the measurement and of vibration signal the method of separating the vibration signal based on EMD decomposition has been studied.As a result,a method of active detecting and separating vibration jamming signal combined with EMD decomposition has been proposed and the validity has been verified.The pressure signal of shock wave has been simulated through the ideal shock wave pressure curve DYNA simulating,the output of pressure sensor exposed respectively to vibration,high temperature and electromagnetic interference environment and white gaussian noise generated by the software in order to find out which one of digital filter,wavelet de-noising and EMD de-noising method is more efficient.The advantages and disadvantages of wavelet de-noising and EMD de-noising method have been analyzed.The shock wave pressure signal which measured on the blasting field has been deal with the noise through EMD de-noising method,which has improved accuracy of the extraction of the pressure peak and calculation of specific impulse.