Design And Application Of Warp-knitted Macro-bend Fiber Strain Sensing Fabric

With the improvement and increasing of people's living standard,the center of health conscious is changing and transferring from medical treatment to precaution and health maintaining,leading to the smart garments for monitoring human physiological parameters attracting more attention.Since the optical fiber macro-bending sensor possesses some features such as small size,light weight,high sensitivity,anti-electromagnetic interference,and compatible with yarns,etc.the investigation of optical fiber macro-bending sensing fabrics for making wearable smart garments is becoming one of the hot points.In this study,the optical fiber macro-bending sensing fabric was made with warpknitted structure and inlaid optical fiber,combing the sensing fiber and fabric structure in one step.The inlaid optical fiber changes it shape along with the stretch of the fabric.This results in the change of output signals,and demonstrates sensing effect.The sensing fabric consists of ground structure and sensing unit.In this study,the macro-bending sensing theory and fabric structure were analyzed,and fabric samples were knitted with a D1000(diameter 1000?m)Plastic Optical Fiber(POF)inlaid in semi-circles(radius 10mm)in the fabric plane based on the ground structures of the Locknit and a modified Sharkskin(cord lap in back guide bar,satin lap in front guide bar)structures,respectively.After that,these sensing fabrics were tested,and the transmission performance of optical signal during fabric stretching process was analyzed.Respiratory rate is an important indicator of human health assessment.Based on the developed sensing fabrics,In this study,a product prototype—macro-bend breathing band was designed and made in our lab.This band is composed of sensing section and extension section.The sensing section was knitted in the Locknit structure and partial lay-in structure with 4 sensing units.The extension section was made in elastic band and Velcro.After preliminary test,the breathing band is proved useful and feasible.This lays a foundation for further research on the smart textiles for monitoring human respiratory.