The behavior of a postbuckled embedded delamination was studied using geometrically-nonlinear 3-D finite element analysis. Nonlinearities due to both significant rotations and delamination face contact were considered. The analysis showed that the postbuckling deformation can lead to matrix cracking and fiber breakage in addition to delamination growth. These calculations agree qualitatively with experimental results. Also, for the configuration analyzed and moderate strain levels, the strain-energy release rates can be calculated with reasonable accuracy without including contact effects in the analysis
Get full access to this article
View all access options for this article.
References
1.
Kachanov, L.M.1976. "Separation Failure of Composite Materials," Polymer Mechanics, 12:812-815.
2.
Konishi, D.Y. and W.R. Johnson.1979. "Fatigue Effects on Delammations and Strength Degradation in Graphite/Epoxy Laminates," Composite Materials: Testing and Design, Fifth Conference, ASTM STP 674, American Society for Testing and Materials, pp. 597-619.
3.
Whitcomb, J.D.1981. "Finite Element Analysis of Instability-Related Delamination Growth," J. Composite Materials, 15:403-426.
4.
Chai, H., C.D. Babcock and W.G. Knauss.1981. "One Dimensional Modelling of Failure in Laminated Plates by Delamination Buckling," Int. J. Solids Structures, 17(11):1069-1083.
5.
Webster, J.D.1981. "Flaw Criticality of Circular Disbond Defects in Compressive Laminates," Center for Composite Materials Report No. 81-03.
6.
Ashizawa, M.1981. "Fast Interlaminar Fracture of a Compressively Loaded Composite Containing a Defect," Presented at the Fifth DOD/NASA Conference on Fibrous Composites in Structural Design , New Orleans, LA, Jan. 1981 (also available as Douglas Paper No. 6994).
7.
Gillespie, J.W. and R.B. Pipes.1984. "Compressive Strength of Composite Laminates with Interlaminar Defects," Composite Structures, 2(1):49-69.
8.
Whitcomb, J.D.1984. "Strain-Energy Release Rate Analysis of Cyclic Delamination Growth in Compressively Loaded Laminates," Effects of Defects in Composite Materials, ASTM STP 836, American Society for Testing and Materials, pp. 175-193.
9.
Bottega, W.J.1984. The Mechanics of Delamination in Composite Materials . Ph.D. Dissertation, Yale University.
10.
Yin, W.L.1985. "Axisymmetric Buckling and Growth of a Circular Delamination in a Compressed Laminate," International Journal of Solids and Structures, 21.503-514.
11.
Sallam, S. and G.J. Simitses.1985. "Delamination Buckling and Growth of Flat, Cross-Ply Laminates," Composite Structures, 4:361-381.
12.
Chai, H. and C.D. Babcock.1985. "Two-Dimensional Modelling of Compressive Failure in Delaminated Laminates," J. Composite Materials , 19:67-98.
13.
Whitcomb, J.D. and K.N. Shivakumar.1987. "Strain-Energy Release Analysis of a Laminate with a Postbuckled Delamination," Fourth International Conference on Numencal Methods in Fracture Mechanics, Pineridge Press, pp. 581-605. Also available as NASA TM 89091.
14.
Whitcomb, J.D.1990. "Mechanics of Instability-Related Delamination Growth," Composite Materials: Testing and Design (Ninth Volume), ASTM STP1059, pp. 215-230.
15.
Whitcomb, J.D.1989. "Three-Dimensional Analysis of a Postbuckled Embedded Delamination," J. of Composite Materials , 23:862-889.
16.
Whitcomb, J.D.1989. "Predicted and Observed Effects of Stacking Sequence and Delamination Size on Instability-Related Delamination Growth," J. of Composites Technology and Research , 11(3):94-98.
17.
Whitcomb, J.D.1988. "Instability-Related Delamination Growth of Embedded and Edge Delaminations," Ph.D. Thesis, Virginia Polytechnic Institute and State University.
Wang, S.S. and I. Choi.1983. "The Mechanics of Delamination in Fiber-Reinforced Composite Materials, Part I-Stress Singularities and Solution Structure," NASA CR-172269.
