Ultrasonic Backscatter Rotation Scanner for Detection of Ply Bends and Fiber Wrinkles
Is Version Of
Begun in 1973, the Review of Progress in Quantitative Nondestructive Evaluation (QNDE) is the premier international NDE meeting designed to provide an interface between research and early engineering through the presentation of current ideas and results focused on facilitating a rapid transfer to engineering development.
This site provides free, public access to papers presented at the annual QNDE conference between 1983 and 1999, and abstracts for papers presented at the conference since 2001.
Fiber wrinkles and ply bends in structures composed of laminated, fiber reinforced plastic materials are known to degrade performance under design load conditions. Such flaws can inadvertently be manufactured into structures, such as solid rocket motor (srm) cases and nozzles, and generally are difficult to detect. For structures such as nozzles, plies are not coplanar with the nozzle wall, but have an out-of-plane direction. Such materials offer an increased challenge for detection of ply bends and fiber wrinkles. Advanced nondestructive evaluation (NDE) methods are needed for detection of these flaws so that manufacturing processes can be characterized and improved and, also, to prevent the usage of defective materials. Ultrasonic backscatter-based methods have been demonstrated to be sensitive to fiber direction and to transverse cracks in composite laminate plates and test panels with plies lying in the plane of the plate or panel [1–5]. Backscatter methods, thus, provide a viable foundation for addressing the similar problem of ply bends and fiber wrinkles in composites with out-of-plane plies. This paper describes an improved ultrasonic backscatter method for detection of ply distortions in structures with out-of-plane ply orientations.