Structural Health Monitoring of an Aircraft Panel Using Continuous AE Sensor (Preprint)

摘要

Fatigue crack growth during the service of aging aircrafts has become an important issue and the monitoring of such cracks in hot spots is desirable. A structural health monitoring sensor system that uses acoustic emission technique for monitoring safety of such structures is described in this report. A 'continuous sensor' formed by connecting multiple sensor nodes in series arrangement to form a single channel sensor is proposed to monitor acoustic emission signals. This report describes the work performed for monitoring fatigue cracks in aluminum lap joints. The traditional AE sensors as well as bonded continuous sensors described above were used to monitor acoustic emission signals emanating from crack growth in aluminum 7075-T6 and 2024-T3 specimens. It was possible to differentiate the signals due to crack growth from noise signals arising from fretting and RF pickup. The sensitivity of the bonded continuous sensor was comparable to commercial high sensitivity resonant frequency AE sensors. The relationship between acoustic emission parameters and the crack growth rate in the aluminum specimens is examined.