Study on the core-shell structured fiber type strain sensor with load bearing characteristics in composite structures

Abstract

In this study, core-shell structured strain sensors with a sandwich structured conductive layer, which have high load carrying capacity as well as high sensing performances were fabricated by using a dry-jet wet spinning system. The core part of the fiber sensor was made of ultra-high molecular weight polyethylene (UHMWPE) which has high modulus and strength. The shell parts of the fiber sensor as an electrically conductive layer were composed with the sandwich structured MWCNT conductive coating layers to enhance the sensing performances. An outer surface of the fiber sensor was coated with a thin polyurethane (PU) layer for the electrical insulation. The scanning electron microscope (SEM) was used to confirm the formation of the core-shell structure of the fiber sensor. Single filament tensile tests were performed to estimate the mechanical properties of the fiber sensors. Strain sensitivity and repeatability of the fiber sensors were measured using an LCR meter during a static and dynamic tensile test, respectively. From the results, we confirmed that the core-shell structured sensor fibers with sandwich structured MWCNT layer showed significantly enhanced the mechanical properties by controlling the drawing condition and sensing performances including sensitivity and linearity by controlling structural configuration of the conductive layers as well.