Location

La Jolla, CA

Start Date

1-1-1998 12:00 AM

Description

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.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

17B

Chapter

Chapter 5: Engineered Materials

Section

Composites

Pages

1229-1235

DOI

10.1007/978-1-4615-5339-7_159

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Ultrasonic Backscatter Rotation Scanner for Detection of Ply Bends and Fiber Wrinkles

La Jolla, CA

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.