A Study on the Prediction of Elastic Modulus in Short Fiber Composite Materials

단섬유 복합재료의 탄성계수 예측에 관한 연구

  • 김홍건 (전주대학교 기계공학과)
  • Published : 2005.02.01


Theoretical efforts are performed to extend the formulation of NSLT(New Shear Lag Theory) for the prediction of the elastic modulus in short fiber composite. The formulation is based on the elastic stress transfer considering the stress concentration effects influenced by elastic modulus ratio between fiber and matrix. The composite modulus, thus far, is calculated by changing the fiber aspect ratio and volume fraction. It is found that the comparison with FEA(Finite Element Analysis) results gives a good agreement with the present theory (NSLT). It is also found that the NSLT is more accurate than the SLT(Shear Lag Theory) in short fiber regime when compared by FEA results. However, The modulus predicted by NSLT becomes similar values that of SLT when the fiber aspect ratio increases. Finally, It is shown that the present model has the capability to predict the composite modulus correctly in elastic regime.


Composites;Elastic Modulus;FEA;Fiber Aspect Ratio;Fiber Volume Fraction;SLT;NSLT


  1. Agarwal, B. D., Lifsitz, J. M. and Broudtman, L. J., 1974, 'Elastic-Plastic Element Analysis of Short Fiber Composites,'Fiber Science and Technology, Vol. 7, pp. 45-62
  2. Agarwal, B. D. and Broutman, L. J., 1980, 'Analysis and Performance of Fiber Composites,' Johns Wiley and Sons, New York, pp. 71-104
  3. Cox, H. L., 1952, 'The Elasticity and Strength of Paper and Other Fibrous Materials,' British Jounal of Applied Physics, Vol. 3, pp. 72-79
  4. Kim, H. G., 1994, 'Stress Transfer in shear Deformable Discontinous Composites,' KSME Jounal, Vol. '8, No.4, pp. 475-484
  5. Nardone, V. C. and Prewo, K. M., 1986, 'On the Strength of Discontinuous Silicon Carbide Reinforced Aluminum Composites,' Scripta Metallurgica, Vol. 20, pp.43-48
  6. Nardone, V. C., 1987, 'Assessment of Models used to Predic the Strength of Discontinuous Silicon Carbide Reinforced Aluminum Alloys,' Scripta Metallurgica, Vol. 21, pp. 1313-1318.
  7. Taya, M. and Arsenault, R. J., 1987, 'A Comparison Between a Shear Lag Type Model and an Eshelby Type Model in Predicting the Mechanical Properties of Short Fiber Composite,'Scripta Metallurgica, Vol. 21, pp. 349-354
  8. Kim, H. G., 1998, 'Analytical Study on the ?Elastic-Plastic Transition in Short Fiber Reinforced Composites,' KSME International Journal, Vol. 12, No.2, pp. 257-266
  9. Kim, H. G. and Yang, S. M. and Noh, H. G., 2003, 'Stress Analysis of a Discontinuous Composite Using Mechanics of Materials Approach,' KSMTE, Vol. 12, No.4, pp.63-69
  10. Kim, H. G. and Noh, H. G., 2004, 'Effect of Elastic Modulus Ratio on Internal Stresses in Short Fiber Composites,' KSMTE, Vol. 13, No.4, pp. 73-78
  11. Clyne, T. W., 1989, 'A Simple Development of the Shear Lag Theory Appropriate for Composites With a Relatively Small Modulus Mismatch,' Mater.Sci.Eng.A, Vol. 122, p. 183
  12. Jiang. Z. et aI., 1998, 'An Analytical Study of the Influence of Thermal Residual Stresses on the Elastic and Yield Behaviors of Short Fiber-Reinforced Metal Matrix Composites,' Mater.Sci.Eng.A, Vol. 248, pp. 256-275
  13. Starink, M. J. et aI., 1999, 'Shear Lag Models for Discontinuous Composites: Fibre End Stresses and Weak Interface Layers,' Mater.Sci.Eng.A, Vol. 270, pp. 270-277.