An investigation was performed to study the effects of reinforcing strips on the notch strength and failure response of laminated composites. A three-dimensional finite element method 3DPDCOM which combined the commercial ABAQUS code with a progressive failure analysis was developed for the study. Composite specimens containing a cutout with or without unidirectional reinforcing strips were tested to verify the model predictions. The test data and numerical simulations proved to be in agreement with each other. Results showed that the notch strength and damage progression of composite laminates could be affected significantly by adding reinforcing strips in front of notches such as crack tips and cutouts. The change in notch strength strongly depended upon the geometry, properties, and bond strength of the reinforcing strips. The strips could significantly alter the failure progression and failure modes in composite plates.
Get full access to this article
View all access options for this article.
References
1.
1. Sun, C.T. and Luo, J. (1985). Failure Loads for Notched Graphite Epoxy Laminates with Softening Strip, Composite Science and Technology, 22(2): 121–133.
2.
2. Dharani, L.R. (1987). An Assessment of Buffer Strips for Reduction of Stress-Concentration at Cutouts in Composite Laminates, Composites Science and Technology, 30(3): 221–231.
3.
3. Meyer, E.S. and Dharani, L.R. (1991). Stress-Concentration at Circular Cutouts in Buffer Strip Laminates, AIAA Journal, 29(11): 1967–2192.
4.
4. Kishore, K.B. and Viswanath, B. (2001). Studies of the Impact Response of Carbon-Epoxy Laminates with and without Buffer-Strip Layers, Composite Interfaces, 8(1): 41–45.
5.
5. Poe, C.C. and Kennedy, J.M. (1980). An Assessment of Buffer Strips for Improving Damage Tolerance of Composite Laminates, Journal of Composite Materials, Supplement, 14: 51–70.
6.
6. Kennedy, J.M. (September, 1991). Damage Tolerance of Woven Graphite/Epoxy Buffer Strip Panels, Journal of Composite Materials, 25: 1218–1241.
7.
7. Palmer, R.J., Dow, M.B. and Smith, D.L. (1990). Development of Stitching Reinforcement for Transport Wing Panels, NASA CP 3104, Part 2, pp. 621–646. October 29–November 1.
8.
8. Kullerd, S.M. (1992). The Combined Effect of Glass Buffer Strips and Stitching on the Damage Tolerance of Composites, NASA ACT 3178, Part 1, pp. 433–452, June 8–11.
9.
9. Whitney, J.M. and Nuismer, R.J. (1974). Stress Fracture Criteria for Laminated Composites Containing Stress Concentrations, Journal of Composite Materials, 8: 253–265.
10.
10. Masters, J.E. and Reifsnider, K.L. (1982). An Investigation of Cumulative Damage Development in Quasi-Isotropic Graphite/Epoxy Laminates, Damage in Composite Materials, ASTM, STP 775, 40–46.
11.
11. Groves, S.E., Harris, C.E., Highsmith, A.L., Allen, D.H. and Norvell, R.G. (March, 1987). An Experimental and Analytical Treatment of Matrix Cracking in Cross-Ply Laminates, Experimental Mechanics, 73–79.
12.
12. Caslini, M., Zanotti, C. and O’Brien, T.K. (1987). Study of Matrix Cracking and Delamination in Glass/Epoxy Laminates, Journal of Composite Technology and Research, 9(4): 121–130.
13.
13. Lim, S.G. and Hong, C.S. (1989). Prediction of Transverse Cracking and Stiffness Reduction in Cross-Ply Laminated Composites, Journal of Composite Materials, 23: 695–713.
14.
14. Awerbuch, J. and Madhukar, M.S. (1985). Notched Strength of Composite Laminates: Predictions and Experiments–A Review, Journal of Reinforced Plastics and Composites, 4: 1–159.
15.
15. Shahid, I. and Chang, F.-K. (1995). An Accumulative Damage Model for Tensile and Shear Failures of Laminated Composite Plates, Journal of Composite Materials, 29(7): 926–981.
16.
16. Hung, C.-L. and Chang, F.-K. (1996). Bearing Failure of Bolted Composite Joints. Part II: Model and Verification, Journal of Composite Materials, 30(12): 1359–1400.
17.
17. Qing, X.L., Sun, H.T., Dagba, L. and Chang, F.-K. (2000). Damage-Tolerance-Based Design of Bolted Composite Joints, Composite Structures Theory and Practices, ASTM STP 1383. In: Grant, P. (ed.), American Society for Testing and Materials, pp. 243–272, West Conshohocken, PA.
18.
18. Sun, H.T., Chang, F.-K. and Qing, X.L. (2002). The Response of Composite Joints with Bolt-Clamping Loads: Part I–Model Development, Journal of Composite Materials, 36(1): 47–67.
19.
19. Sun, H.T., Chang, F.-K. and Qing, X.L. (2002). The Response of Composite Joints with Bolt-Clamping Loads: Part II–Model Verification, Journal of Composite Materials, 36(1): 69–92.
20.
20. Hashin, Z. (1987). Analysis of Orthogonally Cracked Laminates Under Tension, Journal of Applied Mechanics, 54: 872–879.
21.
21. Nuismer, R.J. and Tan, S.C. (1988). Constitutive Relations of a Cracked Composite Lamina, Journal of Composite Materials, 22: 306–321.
22.
22. Tan, S.C. and Nuismer, R.J. (1989). A Theory for Progressive Matrix Cracking in Composite Laminates, Journal of Composite Materials, 23: 1029–1047.
23.
23. Sun, C.T. and Jen, K.C. (1987). On the Effect of Matrix Cracks on Laminate Strength, Journal of Reinforced Plastics and Composites, 6: 208–222.
24.
24. Tsai, C.L. and Daniel, I.M. (1991). The Behavior of Cracked Cross-Ply Composite Laminates Under Simple Shear Loading, Composite Engineering, 1(1): 3–11.
25.
25. Hahn, H.T. (1973). Nonlinear Behavior of Laminated Composites, Journal of Composite Materials, 7: 257–271.
26.
26. (1998). Hibbit, Karlsson & Sorensen Inc., ABAQUS/Standard User’s Manual, Vol. I, Hibbit, Karlsson & Sorensen Inc., Pawtucket, Rhode Island, USA.
