Research On Spacecraft Debris Impact Sensing And Locating Technology Based On Acoustic Emission

With the development of the aerospace industry in various countries,the number of space debris continues to grow,which poses a serious threat to the safe operation of in-orbit spacecraft.Therefore,it is especially important to sense and locate spacecraft and space debris impact.In order to ensure that the spacecraft has sufficient mechanical strength and is lightweight,the stiffeners are usually arranged on the outer surface of the sealed bulkhead.The propagation characteristics of the impact signal in the stiffened plate are very complicated.Although the prior art is capable of accurately locating the source of impact in the flat plates,there is still no effective solution for impact source location in stiffened plates with high stiffeners.Therefore,the impact sensing and locating technology of the spacecraft sealed bulkhead is studied.In order to obtain the influence law of stiffeners on the propagation characteristics of Lamb waves,the space station bulkhead model with periodic stiffeners is taken as the research object,and it is studied based on finite element simulation combined with experimental methods.The energy coefficient used to quantify the effect of stiffeners is proposed.Based on parameters of the model of manned spacecraft’s sealed bulkhead,the simulation model is established.The influence of the number of stiffeners and the propagation paths on the propagation characteristics of the Lamb wave is studied and discussed.The results show that the stiffener has no effect on the propagation velocity of the Lamb wave.Compared with the flat plate,the stiffener attenuates the signal,and the more the number of stiffeners,the more serious the attenuation is.The energy coefficient curve fluctuates with increasing frequency,and the effect of the stiffener on the Lamb wave is equivalent to a comb filter and has a clear pass band in the 100-200 k Hz band.In order to carry out the experimental research on impact location in spacecraft stiffened plates,the impact non-destructive simulation experiment system and the projectile impact experimental system were built and experiments were carried out.In order to solve problems of impact source localization in a high-strength stiffened plate,the adaptive energy compensation threshold filtering method is proposed.The effectiveness of the method is verified by experiments.The influence of two key parameters of the filter frequency band and threshold on the locating result is discussed,and the source of the locating error is analyzed.For the projectile impact experiment,when the filter frequency band is 100-200 k Hz,the locating result is optimal.The average absolute error is 7.0 mm,the average relative error is 0.86%,and the error standard deviation is 3.5 mm,and the locating result meets the application requirements.This study generates fresh insights into the impact location technology in high-strength stiffened plates and provides a reference for in-orbit spacecraft health monitoring systems.