Effects of Base Fabric Parameters on the Electro-Mechanical Behavior of Piezoresistive Knitted Sensors

Strain sensors embedded into fabric structure are one of the most interesting research areas for health and engineering monitoring. In this paper, a textile-based strain sensor has been developed using an intrinsically conductive stainless steel-polyester plain knitted fabric. The influence of fabric structural parameters, such as loop length on electro-mechanical properties of sensors was studied under a tensile fatigue set. Knitted fabric structure deformation during tensile fatigue was monitored and image processed. Peak fitting of electric resistant waveforms (ERWs) and tensile fatigue versus time were performed to analyze the ERWs behavior in detail wherein the entire elongation of knit strain sensor partitioned into two distinct phases, such as loop head and loop leg sections. The results evidenced a discrepancy between loop head and loop leg elongation rate at the stretching onset and end of relaxing phase. The ERW with the higher resolution was obtained using the longest loop length along with the higher extension.