The most important phases during drilling composite laminates are close to the entry and exit where extensive damage in terms of delamination can occur due to 'peel-up' and 'push-out' effects respectively. Drill forces generate interlaminar stresses in- between plies. When the local compressive stresses at the hole periphery exceed the interlaminat stresses in the matrix rich region, crack is initiated and propagates in a stable manner. The model in this paper considers the strain energy required to cleave apart the resin layer between two fibre layers. Attempt is made based on criterions of Linear Elastic Fracture Mechanics (LEFM) to evolve a combined approach which incorporates Hochen and Daran model to predict the location of delamination and then use Uniform Double Cantilever Beam (UDCB) model to predict the delamination crack size.
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 2, pages 489 - 494 Publisher:Ashgate Publishing Company
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