Abstract:

In order to strdy the structural health monitoring of three-dimensional (3-D) braided composites in real-time, a method for constructing smart 3-D braided composites was proposed. The method is based on the structure of three-dimensional six-direction braided composites.In the process, carbon nanowire sensors were embedded into the composite in the form of axial yarn and sixth direction yarn by three-dimensional four-step and six-directional braiding. The internal damage monitoring system of 3-D braided composites based on carbon nanowires was established. The main characteristics of resistance value matrix measured by  carbon nanowires were analyzed using singular value decomposition of four partitioned matrix. The exact internal damage positions of samples were calculated  using main characteristics of the matrix. Five different types damage samples were aadopted in experiments. The experimental results show that the internal damage localization of samples by the method are consistent with the actual damage. The damage location coordinate error is less than 1. This study will provide a theoretical basis for the development of the structural health monitoring of smart 3-D braided composites.

Key words: three-dimensional six-directional braided composite, carbon nanowire sensor, interior danage, nondestructive testing, singular value deconposition