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Designed for use in the construction, aerospace and automotive industries to monitor structural health without the need for an external power source, the technology was developed by researchers at Tohoku University in Sendai, Japan.
“CFRP is very strong and light. It’s used in aeroplanes, wind turbines and other large structures. However, it can fail suddenly when cracks grow inside. Finding these cracks early is difficult, and many structures cannot easily use batteries or wired sensors. A self-powered sensing solution is strongly needed,” said assistant professor Zhenjin Wang.
To make CFRP smarter, the researchers integrated a piezoelectric nanocomposite that converts mechanical energy into electrical energy. The piezoelectric nanocomposite is made of piezoelectric nanoparticles and epoxy, which helps balance electrical performance and mechanical strength. The team used a lead-free piezoelectric material, potassium sodium niobate, to improve its safety and environmental credentials.
“Our material turns vibration into information. Crack growth can be reflected in the timing of the wireless signals, which enables fully autonomous structural monitoring to support safer aircraft and energy systems,” Wang said.
The team tested both the mechanical strength of the composite and its ability to generate electricity. Under vibration, the material produced an open-circuit voltage of up to 13.6 volts. When artificial cracks were introduced between the CFRP and piezoelectric nanocomposite layers, the output voltage and resonant frequency decreased as the cracks became longer. “This means the material does not only harvest energy, but it can also ‘sense’ internal damage through changes in its electrical response,” a Tohoku announcement said.
Based on that behaviour, the researchers proposed a new approach that combines energy harvesting, sensing and structural health monitoring in a single material system. “With the piezoelectric ‘brain’, the CFRP can harvest electricity from vibration and use it to monitor key conditions such as acceleration and pressure, while sending the data wirelessly to a computer without any external power supply. In addition, internal damage such as delamination can be detected by analysing changes in the timing of the received wireless signals,” the announcement continued.
Wang added: “Today, inspections need sensors, wires and power supplies. This new material works by itself. It reduces cost, weight and maintenance, and improves safety in places where power is limited. In addition to supporting safer aircraft and energy systems, our research will help future smart materials research and advance battery-free sensor technology.”
Additional testing is needed to confirm the durability and stability of the composite, the announcement said.
The technology was highlighted in a paper published in the International Journal of Smart and Nano Materials.
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