Magnetostrictive sensors for composite damage detection and wireless structural health monitoring

The efficacy of magnetostrictive ribbon actuators as aerospace composites impact damage detectors has been investigated through finite-element modeling and experimental studies, investigating both the sensitivity of magnetostrictive ribbons embedded and surface mounted using the tensile and three-point bending tests. From the modeling, it was found that the surface-mounted ribbons increased Young's modulus of the system compared to the composite alone but caused the ribbons to delaminate from the surface before failure. The embedded ribbons did not appear to affect the structural properties of the composite, which was observed through the three-point bending tests carried out. From the impact damage tests, it was determined that the ribbons had to be embedded two-ply below the surface to measure impact energies greater than 1.6 J. For surface-mounted ribbons, damages of 1.6 J to the surface could be detected and pinpointed for two ribbons 10 mm apart. We also demonstrate in a simple way how a two-ribbon scheme may be used to determine the damage position in the tested sample, which may be extended for wireless sensing.