Highly Nonlinear Granular Crystal Sensor and Actuator for Delamination Detection in Composite Structures

摘要

We propose a new “granular crystal sensor and actuator” based on highlynonlinear solitary waves (HNSWs) to detect delaminations in composite structures.HNSWs are compactly-supported energy packets, which are generated by a balance ofnonlinear and dispersive effects in nonlinear media. Their unique physical propertiesallow the usage of HNSWs as novel information carrier for nondestructive evaluation(NDE) and structural health monitoring (SHM) applications. Particularly, HNSW’stunability and high power intensity can enhance sensitivity and energy-efficiency,offering advantages beyond the conventional linear-wave based diagnostic schemes.To efficiently generate and propagate diagnostic HNSWs, we assemble a granularcrystal composed of closely packed elastic particles. This granular crystal can functionboth as actuator and sensor, by exciting a composite structure via injected HNSWs toan area of interest and measuring reflected pulses that carry diagnostic informationabout defects. In this study, we demonstrate experimentally the ability to detectdelaminations in a carbon fiber-reinforced polymer (CFRP) composite panel using aprototype of granular crystal sensor/actuator. Preliminary results show that a compactgranular crystal sensor/actuator can successfully detect artificially createddelaminations in a composite panel. Due to the compactness and energy-efficiency ofthe granular crystal sensor/actuator, the proposed diagnostic method has the potentialto become a portable and reliable sensing instrument for inspecting structural damagesin critical areas of composite structures.