Abstract

RODRIGUEZ-GONZALEZ, J. A.; RUBIO-GONZALEZ, C.  and  HERNANDEZ SANTOS, M.. Strain monitoring and damage detection in glass fiber/epoxy composite using carbon nanotubes. RIIIT. Rev. int. investig. innov. tecnol. [online]. 2018, vol.6, n.33. ISSN 2007-9753.

In this work, we investigate the piezoresistive response of a multiscale composite material to self-sense and detect their strain and internal damage under flexural loading. To this aim, a laminated glass of fiber/epoxy was manufactured with multiwall carbon nanotubes (MWCNTs) as electrical nanoparticles to obtain a multi-scale composite laminate with piezoresistive properties. The deposition of MWCNTs onto glass fiber was made by spray coating technique and the manufacture of the laminate by vacuum assisted resin infusion. After manufacturing, beam-type specimens were cut from the laminate and prepared for three-point bending tests and electrical resistance measurements. The piezoresistive curves showed a global (linear and non-linear) behavior in both tensile and compressive surfaces, being positive for tensile side and negative for compression side of the specimen. The results also revealed that electrical resistance change follows the mechanical deformation applied to the sample, which is disrupted when material failure occurs. In the cyclic tests, it was observed that the electrical resistance follows the loading and unloading flexural cycles for the different levels and incremental loading cycles. Thus, the results obtained in this investigation confirm that the composite laminate made of glass fiber/MWCNT/epoxy is able to self-sense and detect its strain and damage under flexural loading through electrical resistance change.

Keywords : Carbon nanotubes; glass fiber/epoxy composite; flexural loading; piezoresistivity.