Fully-integrated carbon nanotube epoxy film sensors for strain sensing in GFRP

Abstract

Structural health monitoring of fiber-reinforced polymer composites becomes more important to ensure a safe and reliable operation. This work demonstrates a method for local matrix modification of glass fiber-reinforced polymers with fully-integrated pre-cured carbon nanotube epoxy thin-film sensors enabling a piezo-resistive strain and damage monitoring. The film sensors were manufactured using a manual film applicator, partially pre-cured for 48 h under lab conditions, cut to shape, and placed on dry glass fiber fabrics before infusion in a resin transfer molding process. Three-point bending tests with sensor films under the upper ply, in the middle, and over the lower ply prove the sensor films' ability for localized strain monitoring. Furthermore, detection of critical buckling is possible in structural parts, as demonstrated in compression tests of coupon specimens and stringer components.