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Showing papers by "Defence Research and Development Laboratory published in 1992"


Book ChapterDOI
TL;DR: In this paper, an axis-symmetric cfrp shell of specific dimensions is presented for X-ray radiography of carbon-fibre-reinforced composites.
Abstract: Publisher Summary This chapter presents an axis-symmetric cfrp shell of specific dimensions. Axis-symmetric composite structures are widely used in aerospace applications. Among the common processing defects, delaminations and voids happen to be most predominant. It is well known that an ideal two dimensional defect of zero thickness like delamination cannot be detected by X-ray radiography. Delamination is defined as a defect whose thickness is small compared to its other dimensions. As the thickness tends to increase and becomes comparable with its planer dimensions, the defect turns into a void. However, even detectability and relative comparison of defects by application of this technique need to be accepted with some amount of caution. The crux of the problem reveals the fact that every single X-ray beam propagating through the component happens to have a different path length, depending on the component geometry and also on the source component-film configuration. Systematic investigations on X-ray radiography of carbon-fibre-reinforced composites are attempted in recent years by a few workers. The workers advocated half-value-layer approach for establishing appropriate energy levels for composite radiography. Though selection of 5EHVL appears to be the most common, 2EHVL, 4EHVL, and 6EHVL exposures were tried out, given the additional complexity of the darkening background and varying component-film distance in tangential radiography.

2 citations