Research On Embedded Underwater Explosion Shock Wave Test System Based On PVDF

At present,the measurement of underwater explosion shock wave is a general test scheme,the pressure sensor is connected to a multichannel universal amplifier through a shielded line,and then,the amplifier is connected with the acquisition card to convert the analog signal into a digital signal,finally,the digital signal is introduced into PC for storage and data processing.Specially aimed at the characteristics of underwater explosion signal,It is not common to study the small and intelligent embedded underwater explosion shock wave testing system.In the field of Defense,especially research on weapons and fortifications in water,It is necessary to measure the time history curve of the shock wave pressure signal.However when measuring under water,the preparation and installation of the equipment is more difficult than the ground,this brings great inconvenience to the research on underwater weapons and ship protection.Therefore,it is necessary to study the customization and miniaturization embedded underwater explosion shock wave testing system.In this paper,an embedded underwater explosion shock wave test system based on PVDF is proposed,set up a whole set of hardware and software platforms,It provides technical support for the power test of underwater weapons.First,through the analysis of the action mechanism and propagation process of the blast shock wave in the water,the mathematical model of the pressure in the stage of shock wave and the stage of a bubble pulsation is given respectively.The analysis shows that the pressure change characteristics of the shock wave signal and the one pulse signal are very different.The former has high frequency and fast change,and the latter is slow in frequency.Therefore,dif?ferent sampling rates need to be adopted to meet the requirements of embedded system for small storage resources and low power consumption.The discretized pressure signal is used as the research object,increase sampling rate by interpolation,reduce the sampling rate by extract.Sampling on the shock wave phase using L-up-sampling,use of M-down-sampling for one stage of bubble pulsation,a variable sampling strategy for embedded underwater shock wave testing system by using H(n).Secondly,the physical,mechanical and electrical properties of PVDF piezoelectric thin film materials are analyzed,establishing the equivalent model of PVDF circuit,determination of piezoelectric signal by current mode.Design of differential interface circuit,in the case of AD8253 making the size of the amplifier module minimum,the magnification can be pro-grammed,direct drive post level AD8275,convert the output signal of the amplifier module from 0 to 3.3V,and input into the AD7612 analog to digital converter.128Mbit’s flash memory to meet the requirements of continuous measurement of the system.Through the design of the whole structure,the hardware of the underwater explosion shock wave testing system based on PVDF is completed and realized.The circuit of the test system is calibrated.Get the sensitivity of the circuit system Kp=0.254mv/bit.Through mathematical analysis,the relationship between the pressure signal of the system and the pressure of shock wave is established.Finally,The control state of shock wave test system is designed by using the finite state machine method,the application of the three spline interpolation method in the reconstruction of the local overpressure signal of the shock wave is also analyzed.Use Python language achieve host computer software.Design equivalent water target loading device to experiment and simulation,the reasons for the error of the simulation and the test are analyzed.The results of KD2004 sensor test system and PVDF embedded test system are close,good waveform con-sistency,It shows that all the work of the embedded underwater explosion shock wave test system based on PVDF is feasible,achieve grow out of nothing.