Application of optic fiber sensors embedded into braided composites

Braided composites have advantages over conventional ply composites, which have limitation of brittle interlaminar. They are the hotspot of advanced material research in recent years. Although 3-D braided composites have good performances, people do not know enough about them, whether in depth or in extent. In this paper a method in which optic fiber sensors embedded into 3-D composites are used to study 3-D braided composites is introduced. The braiding process of optic fiber sensors, optic performances of optic fibers are studied. Several kinds of optic fibers are used. Girder form structures with embedded optic fibers are braided through four-step method and processed through Mold Pressing. Some special measures are taken to prevent damage of the optic fibers. Measurement of some performance parameters of optic fibers shows little changes of those parameters before, after optic fibers being braided into the structures, and after the molding process. A polarimetric type of optic fiber sensors is designed for measuring strain in braided testpieces.