In-Situ Monitoring, Identification and Quantification of Strain Deformation in Composites Under Cyclic Flexural Loading Using Nylon/Ag Fiber Sensor

Despite having vast structural applications, Composites are not exempt from limitations and are susceptible to deforming during operation. Therefore, it is essential to develop in-situ monitoring systems to avoid their catastrophic failure or high repairing cost. So, the objective of this study was to monitor the deformation behavior of composites subjected to cyclic flexural deformation in real-time using a Nylon/Ag fiber sensor. Nylon/Ag fiber sensor was integrated at different direction i.e. 0 degrees, +45 degrees, 90 degrees, -45 degrees gradually between each ply of the composite specimens which were then machined in star shape where each leg signified the direction of the sensor. These specimens were then tested under cyclic flexural deflection at the strain rate of 2mm/min for 10 cycles. Mechanical results of composite specimens and electrical response of each Nylon/Ag sensor fiber showed excellent repeatability however, each Nylon/Ag fiber sensor showed a specific resistance behavior because of their respective position. The increase or decrease in the resistance of the fiber sensor signified the presence of tensile or compressive strain respectively and the intensity of the signal quantified the amount of deformation. The results confirmed that the fiber sensor showed good potential as flexible sensor reinforcement in composites for in-situ monitoring, identification and quantification of the deformation.