From vibration to information: self-powered crack detection and wireless communication in carbon fiber reinforced piezoelectric nanocomposites

Abstract

With the growing expansion of the Internet of Things (IoT), demand is increasing for self-powered sensors that operate without external energy sources. Piezoelectric materials, which convert mechanical energy into electrical energy, offer a promising solution, especially in vibration-rich environments such as aerospace and transportation systems. In this study, a piezoelectric composite was fabricated by laminating carbon fiber-reinforced polymer (CFRP) onto a potassium sodium niobate–epoxy (KNN–epoxy) layer. The CFRP/KNN–epoxy composite serves as both a structural material and an effective energy harvester. The crack-free laminate produced a high piezoelectric voltage of 13.6 V under bending vibration at 262 Hz, with a d33 of 7.8 pC/N. To evaluate damage sensing, interlaminar cracks of varying lengths were introduced. Experiments and finite element analysis revealed a clear quantitative relationship between crack length, electrical output, and energy harvesting capability. The harvested energy was sufficient to power light-emitting diodes (LEDs) and wireless IoT modules. When subjected to vibration, the composite enabled self-powered sensing and wireless data transmission. Furthermore, the charging behavior and transmission interval were influenced by crack length, allowing estimation of the structural health state without external power. These findings demonstrate the potential of CFRP/KNN–epoxy composites as multifunctional materials for self-powered sensing and structural health monitoring.