A real-time active smart patch system for monitoring the integrity of bonded repair on anaircraft structure

Abstract

There currently exists a need to develop a cost-effective, in-service structural healthmonitoring (SHM) system for determining the initial quality of a bonded repair andassessing the long-term durability of the bonded repair on an aircraft structure. In thispaper, a real-time active smart patch system (SPS) based on SMART layer technology isintroduced for monitoring the integrity of bonded repairs. First, an overview of the SPS isgiven for typical metal and composite repairs. To illustrate the capability of the SPS, threeapplications are presented: (1) monitoring of the cure progress of the bonded repairadhesive, (2) detection of the initial artificial disbond between the compositepatch and the metal structure, and (3) monitoring of damage in and around abonded repair during fatigue cycling. The results show that, through the use of areal-time active SPS approach of using sensors placed in, on or around the repair,the initial quality and long-term durability of the repair can be evaluated andmonitored.