This thesis addresses the challenge of composite patch repair of primary structures
by proposing structural health monitoring (SHM) solutions to monitor the integrity
of the bondline. Two smart repair solutions were investigated with three different
sensor technologies. In order to facilitate the data acquisition of multiple sensor
devices, a software architecture was developed and a hardware/software solution
was designed for Lamb waves acquisition. This data acquisition system proved to
be successful in recording Lamb waves in complex scenarios. The first smart re-
pair relies on piezoelectric transducers (PZTs) only and was developed throughout
different composite repairs of increasing structural complexity. In particular, the
final design was a composite step-sanded repair equipped with ten transducers us-
ing Lamb waves for damage detection. A novel damage detection and localisation
algorithm has been developed and was especially designed to take into account the
complexity of composite patch repair. The approach called Minimal Intersection
Score (MIS) is based on the first wave packet difference between pristine and dam-
age signals of different transmitter-receiver (T-R) pairs intersections in a sparse
array. Its effectiveness has been experimentally validated on the smart repair with
impact detection under environmental conditions. This algorithm proved to be very
robust against temperature. The second smart repair solution uses PZTs and Fiber
Bragg Gratings (FBG) and has two different damage detection techniques at its dis-
posal: strain sensing or hybrid PZT-FBG guided waves. Firstly, the applicability of
an hybrid diagnostic system was demonstrated for detecting an artificial damage at
a skin/stiffener interface of a thick composite structure. Then, a hybrid smart repair
was manufactured with five PZTs and five FBGs embedded in the bondline of the
repair’s top ply. The damage detection efficiency of such hybrid repair was inves-
tigated and presented under temperature variations. A novel calibration procedure
was designed to take into account the FBG reflectivity changes due to temperature
that causes amplitude scaling issues for hybrid Lamb waves measurements. Finally,
this calibration method efficiency was experimentally validated by enhancing the
impact damage detection capabilities of the hybrid smart repair under temperature
variations.