Investigation on the Relation between Structure Parameters and Sensing Properties of Knitted Strain Sensor under Strip Biaxial Elongation

Abstract

Knitted strain sensors with different specifications were made from silver-coated conductive yarn and elastic insulating filament with plating-jacquard technique on a SANTONI seamless knitting machine. The arrangements between conductive loops and insulating loops in a structure unit were varied to investigate the effect of the sensor's structures and parameters on sensitivity and repeatability. The influence of fabric density was explored for designing sensing mechanisms. The sensors were also fabricated with different conductive areas by altering the size of the sensing area. The sensing properties of the sensors were assessed by testing their resistance variations under strip biaxial elongation. The results show that knitted strain sensors with various loop arrangements have shown distinct sensitivity and sensing repeatability. Sensors with different fabric densities display good resistance repeatability under both strip biaxial elongation. In addition, the increment of conductive loop wales makes larger resistance variation of sensors with equal numbers of conductive loop courses, and sensors including similar conductive wales tend to have smaller resistance variation at the highest strain level with the growth of conductive courses.