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

The emergence of new technologies in composite manufacturing and inspection has contributed to significant advancements in the wind energy industry. Unidirectional (UD) glass fibre reinforced epoxy composites are widely used in the manufacturing of wind turbine blades due to their good fatigue resistance. One of the important subjects in wind turbine blades is periodic repair and maintenance. Delamination and crack propagation are common structural issues that make regular inspection necessary in the composites. This study presents a structural health monitoring approach using a novel thermoplastic sensor for damage assessment in UD glass fibre epoxy composite. The thermoplastic sensor, composed of thermoplastic Elium and carbon nanotube materials, was prepared using the material extrusion filament technique. The electrical resistance of the filament was assessed under 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. Three point flexural bending test was conducted for mechanical test and relative resistance change was recorded using a Wheatstone bridge circuit. Sharpe increase in the electrical output indicated that the smart composite is sensitive to damage extension under flexural load. This electro-mechanical evaluation on the composite laminate highlights the potential of the proposed technology for health monitoring of large composite structures, such as wind turbine blades.