In-situ cure monitoring of thick CFRP using multifunctional piezoelectric-fiber hybrid sensor network

Conventional process monitoring techniques rely on point or line measurements and can only monitor very limited physical quantities during the curing process. In this study, an innovative multifunctional piezoelectric-fiber hybrid sensor network is developed for global monitoring of multiple physical quantities during the curing cycle of thick carbon fiber-reinforced polymer (CFRP) composites. Three different approaches based on non-invasive and integrated piezoelectric lead-zirconate-titanate (PZT) sensor network are effectively developed to track the degree of cure and key steps via the velocity and amplitude of the received guided wave. The bare and encapsulated fiber optic sensors are woven into the fabrics along the through-thickness direction before liquid composite molding processing to monitor the key steps and the development of temperature and cure-induced strain gradient. Efforts are also made to perform three-dimensional curing imaging from the measurements of the developed sensor network. Experimental validation demonstrates the effectiveness of the proposed piezoelectric-fiber hybrid sensor network for in-situ and real-time monitoring of multiple physical quantities during cure, contributing to the advancement in smart manufacturing and life-cycle structural health monitoring of composites. [Display omitted]