Research On Shock Wave Testing Technique Against Fragmentation Impact Interference

Shock wave test is one of the main methods to judge the destructive power of the combatant,where the determination of the characteristic parameters of the overpressure field is the main basis for the assessment of the destructive effectiveness.During the test,noise signals such as high temperature,strong magnetism and high-frequency vibration are mixed in the shock wave signal,which interferes with the acquisition of shock wave characteristic parameters.How to effectively suppress the noise signal interference and remove the noise in the test data has become an important part of the acquisition of shock wave characteristics parameters.Firstly,this paper analyzes the existing shock wave test method,completes the system integration design of each functional module of the test device,and realizes the integration of wireless communication,USB reading module and shock wave acquisition and storage circuit,which simplifies the operation process of shock wave test.Secondly,for the vibration noise interference problem,design the sensor damping components,and the vibration mathematical model of the device is established on the basis of the analysis of the damping components’ damping motion,and draws its amplitude-frequency characteristic curve.Analyze the suppression effect of sensor damping components on different frequencies of vibration,compare the amplitude-frequency curve of sensor components without damping design,and conclude that the damping structure can effectively suppress the vibration noise in the effective frequency band of shock wave.Apply LS-DYNA to simulate the vibration suppression effect of vibration damping circles composed of different damping materials,and rubber is selected as the best vibration damping material by using the vibration amplitude and acceleration decay rate of the mounting base as the judgment criteria;the simulation of the vibration suppression effect of vibration damping parts when the broken piece hits the test unit at different speeds shows that the maximum vibration acceleration can be reduced by more than70%.Finally,apply the signal processing algorithm to analyze and process the shock wave signal.The time-frequency analysis of the shock wave signal is performed using empirical modal decomposition,and add new decomposition criteria and sieving criteria to the original algorithm based on the signal characteristics,which reduces the number of shock wave signal decompositions and improves the signal decomposition quality.The wavelet denoising algorithm based on three different threshold functions is applied to process the IMF components obtained from the decomposition,analyze the reconstructed signal characteristics,and discuss its application scope.The underdetermined separation problem is converted into a positivedetermined separation problem by EMD algorithm,and apply the blind source separation algorithm based on time-frequency analysis to realize the extraction of shock wave signal,which can effectively judge the characteristics of shock wave parameters.