A Damage Detection Method Based on Flexible Macro-Fiber Composite

Macro-fiber composite (MFC) transducers exhibit superior directionality and flexibility, as well as a high response to Lamb waves, which endows them an intrinsic advantage in damage detection. This article applies MFC transducers to "active–passive" damage detection, a technique which is not well-documented, on a curved structure. By rationally laying out the actuators and rosette receivers on a curved structure of interest, we are able to detect the baseline-free location of infinitesimal damage in the structure. This study combines computational simulations, theoretical analyses, and experimental validations to investigate directional excitation and reception characteristics, in which the incoming wave direction estimation algorithm of MFC delta rosette structure is obtained and damage is characterized by the intensity image synthesized from error estimation curves of two MFC rosette receivers. Experimental results show that the location errors in pinpointing the damage positions on the curved aluminum plate are all within 10 mm, and this system can effectively detect damage in the structure with up to 5 $\text{m}^{-1}$ curvature. Our preliminary results demonstrate that MFC has the potential to precisely locate damage on complex curved structures and provides a novel testing technique to monitor the health state of complex structures.