A Method of Vacuum Leak Detecting Based on Acoustic Emission Characteristics Analysis

In the view of space science and technology is developing, the number of spacecraft in orbit is increasing. Space environment including vacuum, vibration, alternating temperature, micro-meteorites and space debris threatens the structure safety of spacecraft. Once a leak in the spacecraft structure occurs, the pressure of the capsule will drop, which will have a significant impact on the safety of the astronauts. When a leak occurs, the acoustic signal is generated and a method for vacuum leak detection can be used based on characteristics analysis. In this paper, the vacuum leak detection principle is described, and tested by the proposed experimental platform. By characteristic analysis, the signals generated by three different leak holes of 1.0, 1.5 and 2.0 mm are collected and compared with the background acoustic signal by the pump without leakage. The Experiment data show that the signal frequency of the pump running is below 20 kHz. The leak signal is above 20 kHz, which is obviously distinguished from the background noise. When the diameter of the leak hole increases, the energy of leak signal becomes larger, but the high frequency component in the signal decreases. The characteristics analysis of leak acoustic emission signal in this paper is meaningful to the leak detection of spacecraft.