Edge delamination

A series of experiments was reported by Thouless et al. (1992) who compared observations on buckle-driven delaminations of thin films under plane 

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It is critical that surface treatment conditions be optimized to composite properties since overtreatment as well as undertreatment will degrade composite properties. Typically composite interlaminar shear strength (ILSS), in-plane shear, and transverse tension ate used to assess the effectiveness of surface treatment. More recently damage tolerance properties such as edge delamination strength, open hole compression, and compression after impact have become more important in evaluating the toughness of composite parts. 

Figure 4-61 Free-Edge Delamination-Suppression Concepts...

Due to the complex mixed-mode nature of composite delamination, no closed form solutions have been developed yet to express the influence of governing parameters that control the edge delamination behavior. Under tensile loading, delamination is normally preceded by a number of transverse cracks, particularly in the 90° plies. Because of the presence of these cracks, the location of delamination is not unique as in the case of compressive loading, which invariably results in gross buckling of the laminate. The path of delamination along the axial direction varies... 

Fig. 3,34. Edge delamination test (EDT) (a) specimen configuration (b) typical stress-strain curve (c) outward curvature along specimen edges. After Whitney and Knight (1985).

O Brien, T.K. (1984). Mixed-mode strain energy release rate effects on edge delamination of composites. In Effects of Defects in Composite Materials, ASTM STP 836, ASTM, Philadelphia, PA. pp. 125-142. 

Wang, S.S. (1984). Edge delamination in angle ply composite laminates. AlAA J. 2, 256-264. 

Whitney, J.M. and Knight, M. (1985). A modified free-edge delamination specimens. In Delamination and Debonding of Materials, ASTM STP 876 (W.S. Johnson, ed.), ASTM, Philadelphia, PA, pp. 298-314. 

Fig. 8.12. (a) X-ray radiograph and (b) ultrasonic C-scan image, showing edge delamination in the [ 30°/ 90 ]s laminate of T300 carbon 5208 epoxy matrix. system which has been subjected to axial tension. Reprinted from Kim (1989). with kind permission from FIsevier Science-NI.. Sara Burgerhart straat 25,... 

Chan, W.S. (1991). Design approaches for edge delamination resistance in laminated composites. J. Composites TechnoL Res. 14, 91-96. 

Chan W.S.. Rogers C. and Aker S. (1986). Improvement of edge delamination strength of composite laminates using adhesive layers. In Composite Materials Testing and Design, ASTM STP 893 (J.M. Whitney ed.). ASTM, Philadelphia, PA, 266-285,... 

Kim, D.M. and Hong, C.S. (1992). A simple sublaminate approach to the design of thick composite laminates for suppression of free-edge delamination. Composites Sci. Technol. 43, 147-158. 

Kim, R.Y (1983). Prevention of free-edge delamination, in Proc. of the 28th National SAM PE Symposium, April 1983. 

Whilney, J.M. and Browning. C.E. (1973). Free edge delamination of tensile coupons. J. Composite Mater. 6. 300-303. 

Chiang MYM, Wu WE, He JM, Amis EJ (2003) Combinatorial approach to the edge-delamination test for thin film reliability - concept and simulation. Thin Solid Films 437 197-203... 

COMBINATORIAL EDGE DELAMINATION TEST FOR THIN FILM ADHESION -CONCEPT, PROCEDURE, RESULTS... 

Keywords Combinatorial approach, adhesion, interfacial debonding, thin film, edge delamination, fracture mechanics, finite element... 

Fig. 1 A schematic of the free edge effect and edge-delamination test.

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