<title>Stand-alone remotely interrogated device for the real-time health monitoring of bonded structural repairs</title>

Abstract

Adhesively-bonded fiber reinforced composite patches have been used extensively, over the last two decades, on Royal Australian Air Force aircraft to repair fatigue-cracked metallic aircraft components. The bonded repair to the cracked structure - crack patching - allows the restoration of strength and stiffness to the structure, as well as slowing crack growth by reducing stress intensity. However, especially for repairs to critical components the bonded repair needs continuous health monitoring to ensure structural integrity is not compromised. The ultimate goal for very demanding repair applications is to incorporate sensor, actuators and electronics in repair systems - smart repair systems - to monitor and report on the health of the repair and the repaired structure, as well as to actuate in order to prevent damage or failure of the repaired structure. The initial focus in the development of smart repair systems is on the assessment of new sensors and instrumentation which may be incorporate in bonded repair system in order to achieve on-line measurement of patch integrity and effectiveness. This application would allow the operator to move away from current costly time-based maintenance procedures toward real-time health condition monitoring of the bonded repair and the repaired structure. These systems would allow timely decisions on preventative and schedule maintenance before failure of the repair or repaired structure. To this end a 'stand-alone' data logger device, for the real-time health monitoring of bonded repaired system, which is in lose proximity to sensors on a repair is being developed. The instrumentation will measure, process and store sensor measurements during flight and then allow this data to be down loaded, after the flight, onto a PC, via remote data access.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.