Modeling and Characterization of Fatigue Strength of Laminated Composites with Knitted Fabric Reinforcement

Abstract

Results from both theoretical and experimental investigations on laminated epoxy composites reinforced with plain weft-knitted carbon fiber fabrics of different arrangements subjected to fatigue loads are presented in this paper. The stacking sequences used are [0/0/0/0], [0/45/−45/0], [90/90/90/90], [0/90/90/0], and [90/45/−45/90] where 0 refers to the fabric wale direction and 90 to the course direction. Tensile fatigue with stress control was applied to the laminates as well as to the monolithic matrix material, with a stress ratio of R = 0.1 and a cycling frequency of 5 Hz. The theoretical prediction for the laminate fatigue strength was made using a general methodology, which is a combination of the classical lamination theory and the bridging micromechanics model. The stresses sustained by each lamina layer in the laminate were determined according to the classical lamination theory, whereas the internal fatigue stresses generated in the fiber and matrix materials of the lamina were obtained by virtue of the bridging model. The internal stresses were detected against the constituent fatigue strengths at the similar loading conditions as applied to the laminate. Thus, the laminate fatigue strength was predicted only using the constituent fatigue data and the laminate geometric parameters, which were measured/determined independently. Reasonably good agreement has been found between the predicted and experimental S–N curves of all the five laminates.

Keywords

laminated composites knitted fabric composites fatigue strength S–N curve life prediction micromechanics bridging model experimental correlation

Get full access to this article

View all access options for this article.

References

1. Leong, K.H. , Ramakrishna, S. , Huang, Z.M. and Bibo, G.A. (2000). The potential of knitting for engineering composites – a review. Composites: Part A, 31: 197–220.

2. Kamiya, R. , Cheeseman, B.A. , Popper, P. and Chou, T.W. (2000). Some recent advances in the fabrication and design of three-dimensional textile preforms: a review. Comp. Sci. and Tech., 60(1) 33–47.

3. Huang, Z.M. and Ramakrishna, S. (1999). Development of knitted fabric reinforced composite material for prosthetic application. Advanced Composites Letters, 8(6): 289–294.

4. Ko, F.K. , Pastore, C.M. , Yang, J.M. and Chou, T.W. (1986). Structure and properties of multilayer multidirectional warp knit fabric reinforced composites. Proc. of 3rd Japan–U.S. conference. Tokyo. pp. 21–28.

5. Leong, K.H. , Nguyen, M. and Herszberg, I. (1999). The effects of deforming knitted glass preforms on the basic composite mechanical properties. J. Mater. Sci., 34(10): 2377–2387.

6. Ruan, X.P. and Chou, T.W. (1996). Experimental and theoretical studies of the elastic behavior of knitted-fabric composites. Comp. Sci. & Tech., 56: 1391–1403.

7. Gommers, B. , Verpoest, I. and Houtte, P. (1998), The Mori–Tanaka method applied to textile composite materials. Acta Mater., 46: 2223–2235.

8. Huang, Z.M. , Ramakrishna, S. and Tay, A.A.O. (1999). A micromechanical approach to the tensile strength of a knitted fabric composite. J. Comp. Mater., 33(19): 1758–1791.

9. Huang, Z.M. and Ramakrishna, S. (2000). Micromechanical modeling approaches for the stiffness and strength of knitted fabric composites: a review and comparative study. Composite A, 31(5): 479–501.

10.

10. Ramakrishna, S. and Hull, D. (1993). Energy-absorption capability of epoxy composite tubes with knitted carbon-fiber fabric reinforcement. Comp. Sci. & Tech., 49(4): 349–356.

11.

11. Kang, T.J. and Kim, C. (1997). Mechanical and impact properties of composite laminates reinforced with Kevlar multiaxial warp knit fabrics. Polymer & Polymer Composites, 5(4): 265–272.

12.

12. Yu, T.X. , Tao, X.M. and Xue, P. (2000). The energy-absorbing capacity of grid-domed textile composites. Comp. Sci. & Tech., 60(5): 785–800.

13.

13. Chou, S. , Chen, H.C. and Lai, C.C. (1992). The fatigue properties of weft-knitted fabric reinforced epoxy-resin composites, Comp. Sci. and Tech., 45: 283–291

14.

14. Huang, Z.M. (2001). Simulation of the mechanical properties of fibrous composites by the bridging micromechanics model. Composites Part A, 32(2), 143–172.

15.

15. Bini, T.B. , Ramakrishna, S. , Huang, Z.M. and Lim, C.T. (2001). Structure–tensile property relationship of knitted fabric composites. Polymer Composites, 22(1): 11–21.

16.

16. Carlsson, L.A. and Pipes, R.B. (1987). Experimental Characterization of Advanced Composite Materials. New Jersey: Prentice-Hall.

17.

17. Soden, P.D. , Hinton, M.J. and Kaddour, A.S. (1998). Lamina properties, lay-up configurations and loading conditions for a range of fiber-reinforced composite laminates. Comp. Sci. & Tech., 58: 1011–1022.

18.

18. Gibson, R.F. (1994). Principles of Composite Material Mechanics. New York: McGraw-Hill, Inc.

19.

19. Leaf, G.A.V. and Glaskin, A. (1955). The geometry of a plain knitted loop. J. Textile Inst., 45, T587–T605.

20.

20. Adams, D.F. (1974). Elastoplastic behavior of composites. In: Sendeckyj, G.P. (ed.), Mechanics of Composite Materials. New York: Academic Press. pp. 169–208.