Tangential load measurements by a smart textile composite

A cellular textile composite structure integrated with fiber Bragg grating (FBG) sensors is designed for tangential load distribution measurements. The composite consists of many cylindrical shell cells for which a unit cell is fabricated from polyester and glass woven fabrics and epoxy. FBG sensors are bonded on the surface of the cells. The feasibility of using this cellular composite to measure tangential load distribution is demonstrated by experiments. The strain induced wavelength shift in the FBG sensor has a linear relationship with the tangential force within a definite range. Numerical simulations are created by finite element analysis. The influences of the environmental temperature, thickness, and effective moduli of the composite and the influences of the position and direction of the FBG sensors are discussed. The sensitivities of this device are 0.09 nm/N (for PET tension), 0.05 nm/N (for PET compression), 0.04 nm/N (for glass tension), and 0.03 nm/N (for glass compression), and the measurement ranges are 0- +/- 3.43N (PET) and 0- +/- 4.41N (glass). In this measurement range, the system can be used to monitor the tangential load distribution for a large area.