APPLICATIONS OF ULTRASONIC AND COMPTON BACKSCATTER IMAGING TO THE NDE OF COMPOSITE STRUCTURES

Authors
  1. McRae, K.I.
  2. Finlayson, R.D.
Corporate Authors
Defence Research Establishment Pacific, Victoria BC (CAN)
Abstract
Three-dimensional ultrasonic imaging is applied to the characterization of delamination damage caused by low velocity impact or by the over-stressing of fastener holes in composite structures. Although inappropriate for large area damage detection, this method of ultrasonic imaging is capable of providing detailed information concerning delamination damage. This analysis commences with the acquisition of ultrasonic data representing the three-dimensional volume of the structure. Prior to image formation, a variety of one-dimensional signal processing routines are used to increase the time resolution of the ultrasonic data by wavelet deconvolution or by complete inversion of the ultrasonic data. A series of B- and C-scan images, which provide information on the shape, location and size of the defects, are then extracted from either the raw or processed ultrasonic data sets. These images significantly reduce data storage requirements and are much more easily managed. Image processing techniques, including edge enhancement, low-pass and median filters, as well as linear combinations of multiple images, are then applied for further resolution enhancement and noise reduction. These data acquisition and analysis techniques are used to characterize induced delamination damage in a simulated aircraft composite structure and are applied to the in-service inspection of a CF-18 aircraft.
Keywords
COMPOSITE STRUCTURES;COMSCAN;THREE DIMENSIONAL
Report Number
DREP-PREPRINT-93-65 —
Date of publication
01 Oct 1993
Number of Pages
16
DSTKIM No
94-00098
CANDIS No
136268
Format(s):
Hardcopy;Originator's fiche received by DSIS

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