Strain and crack growth monitoring of aluminum alloy sheet using high-sensitivity buckypaper film sensors

The development of micro-nano sensor technology provides a new method for structural health monitoring. This study focuses on the application of buckypaper (BP) thin film sensors for continuous monitoring of strain and crack evolution in metallic structures. The buckypaper (BP) sensor was prepared by using commercial multi-walled carbon nanotubes (MWCNTs) through dispersion, vacuum filtration and other processes. It has the advantages of high sensitivity, wide detection range and good stability. The BP sensor also has good compatibility with epoxy resin. Thus, epoxy resin was used as the adhesive, and the BP sensor was used to monitor the strain and crack growth of the aluminum alloy sheet (2024-T3). In the structural health monitoring test, strain gauges were used for comparison. Through the electrical monitoring of the BP sensor, the strain field measured by the sensor was consistent with the measurement of the strain gauge. The BP sensor can be used to monitor the crack growth information of metal structures. The results highlight the great potential and robustness of the proposed BP thin-film sensor for online structural health monitoring of metal structures.