1784 B. K Ahn et al edges under no ge-bonded dissimilar orthogonal elastic Research, Grant no. F49620-95-1-0158, and by Hyper- 6. Dundurs, J, Ec Therm High Temperature Composites, Inc, Huntington ormal and shea Beach, CA. The authors also thank Dr N. J. Pagano, Dr 9.36.650-652 G. P. Tandon and Dr G. A. Schoeppner for their sub Reissner, E, On a variational theorem in elasticity. J. Math.Phvs.1950.29,90-95 stantial assistance in utilizing the ADM code in this work fields in composites. Proceedings of the 1991 IUTAM Symposium on Local Mechanics Concepts for Composite REFERENCES Materials Systems, Virginia Polytechnic Institute and State University. 1991,pp.l-16 Pagano, N.J. and Brown I, H. W, The 1. Chawla Interface mechanics and toughness In ing mode in unidirectional brittle-matrix composites Ceramic Matrix Composites. Chapman and Hall, Lon- 3.24.6983. on,1993,pp.291-339 10. Pagano. N.J. On the micromechanical 2. He. M.Y. and Hutchinson. j W.. Crack deflection at an class of ideal brittle matrix composites p modes in a interface between dissimilar elastic materials. IntJ. Solids sion loading of coated-fiber composites. Composites Part Sret.,1989,25,1053-1067. B,1998,29B.93-119 3. Gupta, V, Yuan, J and Martinez, d, Calculation, mea- 11. Pagano, N.J., On the micromechanical failure modes in a surement and control of interface strength in composites class of ideal brittle matrix composites, Part 2: Axial ten J.Am. Ceran.Soc.,1993,76,305-315 sion loading of uncoated-fiber composites. Composites Martinez, D. and Gupta, V, Energy criterion for crack Part B,1998,29B,121-130. deflection at an interface between two orthotropic media. 12. Gustafson, C M. Dutton, R. E and Kerans, R.J.,Fab J.Mech.Phs. Solids,1994,42,1247-1271 rication of glass matrix composites by tape casting. J. 5. He M. Y. Evans. A. G. and Hutchinson. J. w. deflection at an interface between dissimilar elastic 13. Lee, W, Howard, s.J. and Clegg, W.J., Growth of rials: Role of residual stresses. Int.. Solids struct interface defects and its effect on crack deflection and 1,3443-3455 toughening criteria. Acta mater., 1996, 44, 3905-3922Research, Grant no. F49620-95-1-0158, and by Hyper￾Therm High Temperature Composites, Inc., Huntington Beach, CA. The authors also thank Dr N. J. Pagano, Dr G. P. Tandon and Dr G. A. Schoeppner for their sub￾stantial assistance in utilizing the ADM code in this work. REFERENCES 1. Chawla, K. K., Interface mechanics and toughness. In Ceramic Matrix Composites. Chapman and Hall, Lon￾don, 1993, pp. 291±339. 2. He, M.Y. and Hutchinson, J.W., Crack de¯ection at an interface between dissimilar elastic materials. Int. J. Solids Struct., 1989, 25, 1053±1067. 3. Gupta, V., Yuan, J. and Martinez, D., Calculation, mea￾surement and control of interface strength in composites. J. Am. Ceram. Soc., 1993, 76, 305±315. 4. Martinez, D. and Gupta, V., Energy criterion for crack de¯ection at an interface between two orthotropic media. J. Mech. Phys. Solids, 1994, 42, 1247±1271. 5. He, M. Y., Evans, A. G. and Hutchinson, J. W., Crack de¯ection at an interface between dissimilar elastic mate￾rials: Role of residual stresses. Int. J. Solids Struct., 1994, 31, 3443±3455. 6. Dundurs, J., Edge-bonded dissimilar orthogonal elastic wedges under normal and shear loading. J. Appl. Mech., 1969, 36, 650±652. 7. Reissner, E., On a variational theorem in elasticity. J. Math. Phys., 1950, 29, 90±95. 8. Pagano, N. J., Axisymmetric micromechanical stress ®elds in composites. Proceedings of the 1991 IUTAM Symposium on Local Mechanics Concepts for Composite Materials Systems, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 1991, pp. 1±16. 9. Pagano, N. J. and Brown III, H. W., The full-cell crack￾ing mode in unidirectional brittle-matrix composites. Composites, 1993, 24, 69±83. 10. Pagano, N. J., On the micromechanical failure modes in a class of ideal brittle matrix composites, Part 1: Axial ten￾sion loading of coated-®ber composites. Composites Part B, 1998, 29B, 93±119. 11. Pagano, N. J., On the micromechanical failure modes in a class of ideal brittle matrix composites, Part 2: Axial ten￾sion loading of uncoated-®ber composites. Composites Part B, 1998, 29B, 121±130. 12. Gustafson, C. M., Dutton, R. E. and Kerans, R. J., Fab￾rication of glass matrix composites by tape casting. J. Am. Ceram. Soc., 1995, 78, 1423±1424. 13. Lee, W., Howard, S. J. and Clegg, W. J., Growth of interface defects and its e€ect on crack de¯ection and toughening criteria. Acta mater., 1996, 44, 3905±3922. 1784 B. K. Ahn et al