Abstract: The stitching technique as the monolithic molding and low-cost manufacture technique have been widely applied in areaspace. The stitch threads used in stitching process have effects on the nondestructure testing results and the microstate of the stitched composites. The stitch threads have different state inside of the stitched composites with different stitching methods, which have different effects on the nondestructure testing results and the microstate of the stitched composites. In this work, three different stitching ways were studied, which were tufting, chained stitching and locking-type stitching. The impacts of ultrasonic A-scan destructive testing and ultrasonic C-scan destructive testing results and the microstate inside of the stitched composites with the three stitching methods were studied by experiments.

Key words: the ways of stitching, stitched composites, nondestructure testing, microstate