The aim of INDUCER was to provide the possibility to make high integrity adhesive repairs using a unique single multi-functional magnetic sensor for “Smart Curing” the bond and to monitor the structural integrity of the repair in service. INDUCER produced a complete operational chain of equipment, software and sensors that revolutionised the technology of composite repair bonding by combining heating, stress localisation, stress compensation, structural health monitoring, lightning protection and earthing. In this project, the R&D of the advanced new generation bonding equipment with multi-functional magnetic sensors for real time “smart curing”, relief of stresses and integrity monitoring of repaired structures were performed. The participating partners have a range of complementary expertise, resources, and test facilities, which, when combined, met the needs for the completion of a successful project. Bonded composite repaired areas of aircraft structures frequently suffer from a variety of factors that may influence their structural integrity, on either a short or long term basis.
In order to overcome these drawbacks, an innovative “sensorised” composite repair set-up was proposed, combining three different technical achievements through the embedding of a magnetostrictive sensor mesh (i.e. metallic mesh composed of small diameter sensors measuring changes in magnetic property with stress according to magneto-elastic phenomena) in the repair area. The use of this magnetostrictive sensor mesh simultaneously achieved the following effects:
- “Smart” curing of the repair by induction heating. This replaced conventional conduction heating, using resistance powered heating blankets.
- Health monitoring of the repair by interrogating the magnetostrictive sensors at regular maintenance intervals, to acquire data concerning changes in the strain field related to accumulated damage.
- Incorporation of “ancillary functions” such as lightning prot.