Fabrication and characterization of in situ structural health monitoring hybrid continuous carbon/glass fiber–reinforced thermoplastic composite

Sensor element integration is a major challenge in the development of structural health monitoring techniques. A novel, multiple-material, in situ, and integrated additive manufacturing method was proposed for the fabrication of a hybrid continuous carbon/glass fiber–reinforced thermoplastic composite that possesses self-sensing capabilities, and in which continuous carbon fibers were employed as sensory elements. Both mechanical and electrical properties were investigated through monotonic and cyclic flexural loading tests. The results revealed that the integration of continuous carbon fibers within a glass fiber–reinforced thermoplastic composite could achieve in situ structural health monitoring without the degradation of mechanical properties. A fractional change in electrical resistance in terms of flexural load showed an excellent linear repeatability in the elastic range and an irreversible dramatic change when structural damage occurred, which is a prospective indicator of both strain/stress self-sensing and damage detection. Finally, a promising application of the proposed hybrid continuous carbon/glass fiber–reinforced thermoplastic composite on a smart prosthetic socket is discussed.