Abstract
An important method for making smart three-dimensional (3-D) braiding composites is to use embedded carbon nanotube (CNT) yarn sensors with 3-D braiding technology. According to the braiding structure of 3-D six-direction braiding composites, the mathematical model of carrier movement of braiding machine is constructed. The method for calculating the number and length of embedded CNT yarns with intelligent composites is proposed. The characteristics of resistance changing for CNT yarns under loading are analyzed. Experiments show that the error of the length and actual length of the CNT yarn calculated by the Bezier curve is less than 1 %. When the tensile strain exceeds 2 %, the strain of the embedded CNT yarns begins to appear nonlinear. The loading and unloading of the specimen have some influence on the resistance change of the CNT yarn. After the load is unloaded, the CNT yarn will produce the residual resistance.