Carbon nanotubes–Elium nanocomposite sensor for structural health monitoring of unidirectional glass fibre reinforced epoxy composite

The emergence of new technologies in composite laminate manufacturing and inspection can lead to advances in the wind energy industry. Unidirectional (UD)-Glass fibre reinforced epoxy composite laminate is widely using for manufacturing of wind turbine blades as they can tolerate high fatigue loads. One of the important subjects in wind turbine blade is periodic repair and maintenance. Delamination and crack propagation are important issues which often occurs within the composite laminate. In this study Structural health monitoring by using a developed thermoplastic piezoresistive sensor was carried out to evaluate damage extension within the UD-Glass fibre epoxy composite laminate. The thermoplastic sensor contains thermoplastic elium and carbon nanotube materials. It has prepared by material extrusion filament technique. The electrical resistance of a sensitive filament assessed through cyclic loading. The prepared material in the filament shape was embedded in the intermediate layer of UD glass fibre-epoxy composite. To evaluate damage propagation, flexural and electrical tests were carried out on the prepared smart composite laminate simultaneously. 3D point flexural bending test was conducted for mechanical test and relative resistance change was recorded through Wheatstone bridge circuit. Sharpe increase in the electrical resistance output indicated that the smart composite laminate is sensitive to damage extension under flexural test. In this study, the electro-mechanical evaluation on the composite laminate was an indication for potential application of this technique for structural health monitoring of large composite structure such as wind turbine blade. • A thermoplastic piezoresistive filament was fabricated for damage evaluation in UD-glass fibre epoxy composite laminate • Electrical resistance measurement method was used for evaluation of damage propagation during flexural test • The correlation between electrical response and damage extension in the composite laminated showed that the thermoplastic sensor is enough sensitive to internal damage within the composite laminate • The damage extension was also evaluated using the c-scan ultrasonic test