Abstract
Conventional measurements of energy release rates,G I andG II, for delaminations in composite materials, generally utilize loads, crack lengths and simple standard specimen geometries. In this work, a more widely applicable measurement method, using phase shifting moiré and the J integral, is presented. The experimental technique described requires only fringe-pattern information and the elastic constants for the measurements—thus it can be used when the standard methods are inapplicable. Using conventional double-cantilever beam and end-notched flexure specimens, the energy release rate has been measured simultaneously by the moiré method and the standard methods, with good agreement found between the two. This development will for the first time permit the experimental validation of new finite-element routines as they are developed.
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References
Wilkins, D.J., Eisenmann, J.R., Camin, R.A. and Margolis, W.S., “Characterizing Delamination Growth in Graphite-Epoxy,” Damage in Composite Materials, ed. K.L. Reifsneider, Amer. Soc. Test. and Mat., Philadelphia, ASTM STP 775, 168–183 (1982).
Davies, P., “Interlaminar Fracture Testing of Composites,” Technical Report, European Group on Fracture: Polymers and Composites Task Group, protocol for joint round robin EGF/ASTM/JIS (April 1990).
Gray, T.G.F., McKelvie, J., MacKenzie, P.M. andWalker, C.A., “Interferometric Measurement of J for Arbitrary Geometry and Loading,”Int. J. Fract.,24:R,109–114 (1984).
Sutton, M.A., Turner, J.L., Chao, Y.J., Bruck, H.A. andChae, T.L., “Experimental Investigations of Three-Dimensional Effects near a Crack Tip Using Computer Vision,”Int. J. Fract.,53,201–228 (1992).
Creath, K., “Phase-measurement Interferometry Techniques,”Progress in Optics, ed. E. Wolf, Elsevier Science Publishers, Amsterdam,XXVI, p.349–393 (1986).
Greivenkamp, J.E. andBruning, J.H., “Phase Shifting Interferometry,”Optical Shop Testing, ed. D. Malacara, Series in Pure and Applied Optics, John Wiley & Sons, New York, Chap. 14, 501–598 (1986).
Hariharan, P., Oreb, B.F. andEiju, T., “Digital Phase-shifting Interferometry: A Simple Error-compensating Phase Calculation Algorithm,”Appl. Opt.,26 (13),2504–2505 (July1987).
Perry, Jr., K.E. and McKelvie, J., “A Comparison of Phase-shifting and Fourier Methods in the Analysis of Discontinuous Fringe Patterns,”Opt. and Lasers in Eng.,19 (4–5) (1992).
Huntley, J.M., “Noise-immune Phase Unwrapping Algorithm,”Appl. Opt.,28 (15),3268–3270 (Aug.1989).
Goldstein, R.M., Zebker, H.A. andWerner, C.L., “Satellite Radar Interferometry: Two Dimensional Phase Unwrapping,”Radio Sci.,23(4),713–720 (July–Aug.1988).
Sullivan, J.L., “Phase-stepped Fractional Moiré,”Experimental Mechanics,31 (4),373–381 (1991).
Perry, Jr., K.E., “Calculation of Energy Release Rates for Delaminations in Composite Materials,” PhD Thesis, Univ. of Strathclyde (Nov. 1993).
Reinsch, C.H., “Smoothing by Spline Functions,”Numerische Mathematick,10,177–183 (1967).
Forsythe, G.E., Malcolm, M.A. andMoler, C.B., Computer Methods for Mathematical Computations, Prentice-Hall, Inc., Englewood Cliffs, NJ (1977).
Davidson, B.D., “An Analytical Investigation of Delamination Front Curvature in Double Cantilever Beam Specimens,”J. Comp. Mat.,24,1124–1137 (1990).
Kruger, R., Koenig, M. and Schneider, T., “Computation of Local Energy Release Rates Along Straight and Curved Crack Fronts of Unidirectional DCB and ENF Specimens,” The 34th SDM Conf.,AIAA-93-1457-CP,1332–1342 (1993).
Pavier, M.J. andChester, W.T., “Compression Failure of Carbon Fiber-reinforced Coupons Containing Central Delaminations,”Comp.,21,23–31 (1990).
Perry, Jr., K.E. and McKelvie, J., “Mixed Mode Delamination of Carbon-fiber/Epoxy Composites,” Proc. of 1994 Soc. for Exp. Mech. Spring Conf. on Exp. Mech. 635–643 (1994).
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Perry, K.E., McKelvie, J. Measurement of energy release rates for delaminations in composite materials. Experimental Mechanics 36, 55–63 (1996). https://doi.org/10.1007/BF02328698
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DOI: https://doi.org/10.1007/BF02328698