The interlaminar fracture behavior of unidirectionally glass fiber reinforced composites with fiber surface treatments have been investigated in Mode I, Mode II and for a fixed mixed Mode 1/11 ratio. With respect to the loading conditions at the crack tip the double cantilever beam (DCB), the end notched flexure (ENF) and the mixed mode flexure (MMF) specimens were used in order to obtain Mode I, Mode II and mixed Mode I/II critical energy release rates. The data obtained from these tests have been analyzed by using analytical and finite element approaches. The present investigation is focused on the influence of the glass fiber surface treatment on the interlaminar fracture toughness. Glass fibers with two different fiber surface treatments have been investigated. For the DCB test the data reduction from the experiments have been carried out by using six different approaches: the area method. the Berry method, the modified beam analysis, the compliance method and the geometric linear and non-linear finite element analysis. The geometric non-linear finite element analysis of the DCB test was performed firstly. For the ENF test contact and friction along the crack surfaces have been taken into account.
1. Piggott, M. R.1992. "Interface Properties and Their Influence of Fibre-Reinforced Polymers," in T. Vigo and B. Kinzig (eds.), Composite Applications. The Role of Matrix, Fibre and InterfaceNew York: VCH Publishers. pp. 221-266.
2.
2. Sela, N. and O. Ishai. 1989. "Interlaminar Fracture Toughness and Toughening of Laminated Composite Materials, A Review,"Composites, 20:423-435.
3.
3. Albertsen, H., J. Ivens, P. Peters, M. Wevers and I. Verpoest. 1995. "Interlaminar Fracture Toughness of CFRP Influenced by Fibre Surface Treatment: Part I. Experimental Results,"Comp. Sci. Technol., 54:133-145.
4.
4. Chai, H.1986. "On the Correlation between the Mode I Failure of Adhesive Joints and Laminated Composites,"Eng Fract. Mech.24:413-431.
5.
5. Keary, P. E., B. L. Ilcewicz, C. Shar and J. Trostle. 1985. "Mode I Interlaminar Fracture Toughness of Composites Using Slender Double Cantilevered Beam Specimens,"J. Comp. Mater.19:154-177.
6.
6. Zhao, S., M. Gidke and R. Prinz. 1995. "Mixed-Mode Delamination Behavior of Carbon/Epoxy Composites,"J. Reinf. Plast. and Comp.14:804-826.
7.
7. Hashemi, S., A. J. Kinloch and G. Williams. 1990. "Mechanics and Mechanisms of Delamination in a Poly(ether sulphone)-Fibre Composite,"Comp. Sci. Technol.37:429-462.
8.
8. Hashemi, S., A. J. Kinloch and G. Williams. 1990. "The Analysis of Interlaminar Fracture in Uniaxial Fibre-Polymer Composites,"Proc. R. Soc. LondA427:173-199.
9.
9. Yeoung, P. and L. J. Broutman. 1978. "The Effect of Glass-Resin Interface Strength on the Impact Strength of Fiber Reinforced Plastics,"Polymer Eng. and Sci.18:62-72.
10.
10. Davidson, B. D., R. Kruger and M. Konig. 1995. "Three-Dimensional Analysis of Center-Delaminated Unidirectional and Multidirectional Single-Leg Bending Specimens."Comp. Sci. Technol.54:385-394.
11.
11. Davies, P., C. Moulin and H. H. Kausch. 1990. "Measurement of GIC and GIIC in Carbon/Epoxy Composites."Comp. Sci. Technol.39:193-205.
12.
12. Carlsson, L. A., J. W. Gillespie and R. B. Pipes, Jr.1986. "On the Analysis and Design of the End Notched Flexure (ENF) Specimen for Mode II Testing,"J. Comp. Mater.20:594-605.
13.
13. Reeder, J. R. and J. H. Crews, Jr. 1990. "Mixed-Mode Bending Method for Delamination Testing,"AIAA J.28:1270-1276.
14.
14. Hashemi, S., A. J. Kinloch and G. Williams. 1990. "The Effects of Geometry, Rate and Temperature on the Mode 1, Mode II and Mixed-Mode I/II Interlaminar Fracture of Carbon-Fibre/Poly(ether-ether ketone) Composites,".Comp. Mater.24:918-956.
15.
15. Davies, P.et al.1992. "Round-Robin Interlaminar Fracture Testing of Carbon-Fibre-Reinforced Epoxy and PEEK Composites,"Comp. Sci. Technol.42:129-136.
16.
16. Madhukar, M. S. and L. T. Drzal. 1992. "Fibre-Matrix Adhesion and Its Effect on Composite Mechanical Properties," IV. Mode I and Mode II Fracture Toughness of Graphite/Epoxy Composites.J. Comp. Mater.26:936-968.
17.
17th National Symposium on Fracture Mechanics, Albany (New York), 7-9 August, 1984. American Society for Testing of Materials, ASTM STP 905. Philadelphia, pp. 108-123.
18.
18. Hashemi, S., A. J. Kinloch and G. Williams. 1989. "Corrections Needed in Double-Cantilever Beam Test for Assessing the Interlaminar Failure of Fibre-Composites,"J. Materials Sci. Letters, 8:125-129.
19.
19. Davies, P. and M. L. Benzeggah. 1989. "Interlaminar Mode-I Fracture Testing," in R. B. Pipes (ed.), Application of Fracture Mechanics to Composite Materials, Vol. 6K. Friedrich (ed.), Composite Materials SeriesAmsterdam: Elsevier, pp. 81-112.
20.
20. Carlsson, L. A. and J. W. Gillespie, Jr.1989. "Mode-Il Interlaminar Fracture of Composites," in R. B. Pipes (series ed.), Application of Fracture Mechanics to Composite Materials, Vol. 6 K. Friedrich (ed.). Composite Materials Series, Amsterdam, Elsevier pp. 113-157.
21.
21. Zhou, J. and T. He. 1994. "On the Analysis of End-Notched Flexure Specimen for Measuring Mode II Fracture Toughness of Composite Materials,"Comp. Sci. Technol.50:209-213.
22.
22. Maikuma, H., J. W. Gillespie, Jr. and J. M. Whitney. 1989. Analysis and Experimental Characterization of the Center Notch Flexural Test Specimen for Mode II Interlaminar Fracture,"J. Comp. Mater.23:756-786.
23.
23. O'Brien. T. K.1984. "Mixed-Mode Strain Energy Release Rate Effects on the Edge Delamination of Composites," in Effects of Defects in Composite Materials, American Society for Testing of Materials, ASTM STP 836Philadelphia, pp. 125-142.
24.
24. Kinloch, A. J., Y. Wang, J. G. Williams and P. Yayla. 1993. "The Mixed Mode Delamination of Fibre Composite Materials,"Comp. Sci. Technol.47:225-237.
25.
25. Wang, Y. and J. G. Williams. 1992. "Corrections for Mode II Fracture Toughness Specimens of Composite Materials,"Comp. Sci. Technol.43:129-136.
26.
26. Drzal, L. T., M. J. Rich and P. F. Lloyd. 1982. "Adhesion of Graphite Fibres to Epoxy Matrices: 1. The Role of Fibre Surface Treatment,"J. Adhesion16:1-30.
27.
27. Gutowski, W. S., E. R. Pankevicius and D. Y. Wu. 1993. "Controlled Interfaces of Ultra-High Modulus of Polyethylene and Aramid Fibres for Advanced Composites," in Proc. Int. Conf Interfaces IICAMT, Ballart, Australia.
28.
28. Drzal, L. T.1986. "The Interphase in Epoxy Composites."Advances in Polymer Science75:1-31.
29.
29. Plueddemann, E. P.1982. Silane Coupling Agents. New York: Plenum Press.
30.
30. Plueddemann, E. P.1992. "Reminiscing on Silane Coupling Agents." in Silane and Other Coupling AgentsK. L. Mittal (ed.), The Netherlands: VSP BV. Utrecht, pp. 3-19.
31.
31. Ishida, H. A.1986. "Review of a Recent Progress in the Studies of Molecular and Microstructure of Coupling Agents and Their Functions in Composites. Coatings and Adhesive Joints,". Polymer Composites, 5:101-123.
32.
32. Bledzki, A. K., G. Wacker and H. Frenzel. 1993. "Effect of Surface Treated Glass Fibres on the Dynamic Behaviour of Fibre-Reinforced Composites,"Mechanics of Composite Materials, 29:585-591.
33.
33. Wacker, G. 1996. "Experimentell Gestutzte Identifikation Ausgewahlter Eigenschaften Glasfaserverstarkter Epoxidharze unter Bertcksichtigung der Grenzschicht," PhD Dissertation, University of Kassel, Kassel, Germany, (in German).
34.
34. Gibson, R. F.1994. Principles of Composite Material MechanicsMcGraw-Hill.
35.
35. Hojo, M., K. Kageyama and K. Tanaka. 1995. "Prestandardization Study on Mode I Interlaminar Fracture Toughness Test for CFRP in Japan,"Composites, 26:243-255.
36.
36. Broek, D.1986. Elementary Engineering Fracture Mechanics4th Ed.. Dordrecht, The Netherlands: Martinus Nijhoff Publishers.
37.
37. Berry, J. P.1963. "Determination of Fracture Surface Energies by the Cleavage Technique,"J. Appl. Physics, 34:62-68.
38.
38. Hibbitt, Karlson and Sorensen, Inc.1993. ABAQUS User's Manual, Version 5.3Providence Rhode Island.
39.
39. Rybicki, E. F. and M. F. Kanninen. 1977. "A Finite Element Calculation of Stress Intensity Factors by Modified Crack Closure Integral,"Engng. Fracture Mech.9:931-938.
40.
40. Buchholz, F.-G. 1984. "Improved Formulae for the Finite Element Calculation of the Strain Energy Release Rate by Modified Crack Closure Integral Method," in J. Robinson (ed.), Accuracy, Reliability and Training in FEM Technology, Proc. of the 4th World Congr. and Exib. on Finite Element Methods, Interlaken, Switzerland, September 1984Dorset: Robinson and Associates, pp. 650-659.
41.
41. Rikards, R., F.-G. Buchholz and H. Wang. 1995. "Finite Element Analysis of Delamination Cracks in Bending of Cross-Ply Laminates,"Mech. Comp. Mater. and Struct., 2:281-294.
