Ultrasonic assessment of satellite structural components and joints

Abstract

One of the key issues in enabling fast and reliable deployment of space systems is structural qualification before launch. The current qualification process is rather long and may span many months. It is envisioned that structural health monitoring (SHM) could assist with verification of structural assembly during pre-launch procedures and enable diagnosis of satellite components. The proposed satellite SHM system utilizes active sensors to launch and receive elastic waves carrying elasticity information about the structural material. Sensor signatures are analyzed for variation of the elastic behavior due to damage. Satellite structural components typically feature complex geometries involving isogrids and bolted joints. Simple representations of complex structures are studied first, followed by investigation of elastic wave propagation in a realistic satellite panel. The sensor network approach is utilized to detect and locate structural damage. The acousto-elastic method is implemented for diagnosis of bolted joints in the satellite panel. Sensitivity of the method is explored for various damage scenarios and a practical damage detection algorithm is suggested. It is shown that the acousto-elastic method allows for assessment of the structural integrity of complex structural elements with bolted joints.