Embedding stretchable, mesh-structured piezoresistive sensor for in-situ damage detection of glass fiber-reinforced composite

Structural health monitoring of composites is of critical importance for various practical applications. However, it is challenging to accurately monitor the damages of the host composites without compromising their mechanical properties. Herein, a novel bioinspired, mesh-structured film that combines flexibility and stretchability is proposed as an embedded piezoresistive sensor for in-situ damage monitoring. The mesh film composed of carbon nanotubes and polyvinyl alcohol was prepared via a simple doctor-blading method. The embedded mesh film exhibited high compatibility with the composite and has negligible impact on its mechanical properties, which is significantly superior to the implanted solid film leading to severe decreases in both the tensile strength (−15.6%) and flexural strength (−35.5%). This effect is attributed to the fact that the epoxy could infiltrate the pores of the mesh film and form an interconnected interlayer, which is beneficial for preserving the mechanical properties. Meanwhile, the proposed mesh film was endowed with the capacity of in-situ damage detection, which was proved by the excellent coherence between the resistance change of the film and the acoustics detected by a commercial sensor. The excellent ability for damage detection demonstrates the great perspectives of the proposed mesh film for the structural health monitoring of composites. In this work, a novel bioinspired, mesh-structured, nanocomposite film that combines flexibility, stretchability and sensitivity was proposed as an embedded piezoresistive sensor for in-situ damage monitoring. The results showed that the implantation of the mesh film sensor has negligible impact on the tensile fracture strength (−0.39%) and flexural strength (−2.7%) of the host composites. The underlying mechanism was ascribed to its mesh-like, stretchable, thin structure, which improved the infiltration of resin and the interfacial bonding in the embedded sensor vicinity. Moreover, the capability of accurate in-situ damage monitoring and failure warning are achieved, which significantly outperform the prevailing solid film sensor. [Display omitted] •A bioinspired mesh film with flexibility, stretchability was proposed as a piezoresistive sensor for in-situ damage sensing.•The implantation of the mesh film sensor has negligible impact on the mechanical properties of the host composites.•The underlying mechanism is ascribed to the formation of interconnected interlayer with the aid of i