Accurate Damage Localization and Enhanced Mechanical Performance of Self-Sensing Epoxy Nanocomposites Using Graphene Platelets

Recently, there has been growing interest in the use of composites structure with self-sensing functionalities in the aerospace, automotive, and renewable energy industries. However, the integration of sensors such as Fiber Bragg Grating or piezoelectric ceramic transducers into the composite structure can significantly reduce the structure's inherent strength. To address this issue, we present a novel approach for developing self-sensing composites by incorporating graphene platelets (GnPs) as an electric filler into an epoxy matrix. Our method involves the uniform dispersion of GnPs in epoxy, with some GnPs connected to each other to achieve a low electrical threshold of 0.61 vol% in the resulting nanocomposites. The resulting composite film exhibits high sensitivity to tensile strains ranging from 0% to 1.8%, with gauge factors (GFs) ranging from 19 to 172. This variation in GF is due to the calibration process, which relies on the relationship between input and output data and does not require a constant factor. In addition to its high sensitivity to tensile strains, the composite film also demonstrates excellent self-sensing performance for bending deformation. Moreover, the composite film effectively responds to impact damage evolution, making it a promising candidate for practical applications. This work represents an advancement in the development of self-sensing nanocomposites using two-dimensional materials, offering exceptional sensitivity and adaptability for potential future use.