Accession Number : ADA182199

Title :   Research on Advanced NDE (Nondestructive Evaluation) Methods for Aerospace Structures.

Descriptive Note : Final rept. 1 Sep 83-31 Aug 86,

Corporate Author : DAYTON UNIV OH RESEARCH INST

Personal Author(s) : Andrews,Robert J. ; Frock,Brian G. ; Martin,Richard W. ; Fox,Jeffery A. ; Klosterman,Edward L.

Report Date : APR 1987

Pagination or Media Count : 115

Abstract : This report describes the development of new methods of ultrasonic nondestructive evaluation (NDE). Ultrasonic backscatter imaging and imaging using leaky surface waves are applied to locating defects in advanced fiber-reinforced composite materials. High speed digitizers are used to acquire the RF signals of interest and B-scan and C-scan images are generated using a high-precision, automated scanning system developed during this program. Defects such as matrix cracks, multi-level delaminations, ply cuts, and simulated porosity are identified in graphite/epoxy composite samples. Image analysis and digital image enhancement techniques are developed and applied to the digitized images to improve defect detection. Global and local spatial domain image operators are successful in improving spatial resolution and defect detection. Initial results of image segmentation efforts to isolate defects are encouraging.

Descriptors :   *FIBER REINFORCED COMPOSITES, *AEROSPACE CRAFT, *AIRCRAFT PANELS, *ULTRASONIC TESTS, *NONDESTRUCTIVE TESTING, COMPOSITE MATERIALS, AUTOMATION, SCANNERS, SAMPLING, DIGITAL SYSTEMS, IMAGE PROCESSING, OPTIMIZATION, GRAPHITE, LAMINATES, BACKSCATTERING, IMAGES, DEFECTS(MATERIALS), DETECTION, ANALOG TO DIGITAL CONVERTERS, SEGMENTED, AEROSPACE SYSTEMS, STRENGTH WEIGHT RATIO, MICROSTRUCTURE, ANOMALIES, SURFACES, COMPOSITE STRUCTURES, EPOXY COMPOSITES, MICROCRACKING, ACOUSTIC MICROSCOPES, RADIOFREQUENCY PULSES, SIGNALS, RESOLUTION, SPATIAL DISTRIBUTION, POROSITY, SIMULATION, SURFACE WAVES

Subject Categories : Laminates and Composite Materials
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE