Micromechanics on the Rate-dependent Fracture of Discontinuous Fiber-reinforced Plastics

Abstract

Numerical simulation by finite element analysis was used to investigate the relationship between the strength of glass fiber reinforced plastic (GFRP) and fiber length. Load speed dependability was also investigated, since thermoplastic resin used for GFRP exhibits much nonlinear stress—strain behavior and strong dependency on load speed. For this purpose, we conducted a periodic-cell simulation to address the effect of composite microstructure, matrix viscoplasticity, and microscopic damage (fiber break and matrix crack). When the fiber length was varied, the damage pattern was divided into two patterns: fiber-avoiding propagation and fiber-breaking modes of the matrix crack from fiber ends. When the matrix crack easily propagated in a fiber-avoiding way for shorter fiber lengths, the rate-dependent effect of the matrix was significant. Moreover, we considered the length at which the fracture mode changed based on this analysis, and compared it with the conventional critical length given by Kelly. Since the conventional critical length does not ensure improved composite strength, the consideration of the damage mode transition is essential for selecting the appropriate fiber length for strength improvement.

Keywords

fiber-reinforced plastics discontinuous fiber matrix crack fiber break rate-dependence.

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References

Curtin, W.A. ( 1999). Stochastic Damage Evolution and Failure in Fiber-Reinforced Composites, Adv. Appl. Mech., 36: 163-253.

Guedes, J.M. and Kikuchi, N. ( 1990). Preprocessing and Postprocessing for Materials Based on the Homogenization Method with Adaptive Finite Element Methods, Comput . Meth. Appl. Mech. Eng., 83: 143-198.

Gurson, A.L. ( 1977). Continuum Theory of Ductile Rupture by Void Nucleation and Growth: Part I - Yield Criteria and Flow Rules for Porous Ductile Media , Trans. ASME - J. Eng. Mater. Technol., 99: 2-15.

Huang, H. and Talreja, R. ( 2006). Numerical Simulation of Matrix Micro-Cracking in Short Fiber Reinforced Polymer Composites: Initiation and Propagation, Compos. Sci. Technol., 66: 2743-2757.

Kawagoe, M. and Kitagawa, M. ( 1981). Craze Initiation in Poly(Methyl Methacrylate) Under Biaxial Stress, J. Polym. Sci.: Polym. Phys. Ed., 19: 1423-1433.

Kelly, A. ( 1966). Strong Solids, Clarendon Press, Oxford, p. 131.

Kobayashi, S. , Tomii, D. and Shizawa, K. ( 2004). A Modelling and Simulation on Failure Prediction of Ductile Polymer Based on Craze Evolution and Annihilation, Trans. Jap. Soc. Mech. Eng. A, 70: 810-817 (in Japanese).

Liu, H.T. , Sun, L.Z. and Ju, J.W. ( 2006). Elastoplastic Modeling of Progressive Interfacial Debonding for Particle-Reinforced Metal-Matrix Composites, Acta Mech. , 181: 1-17.

Matous, K. and Geubelle, P.H. ( 2006). Multiscale Modeling of Particle Debonding in Reinforced Elastomers Subjected to Finite Deformations, Int. J. Numer. Meth. Eng., 65: 190-223.

10.

Murakami, D. , Kobayashi, S. , Torigaki, T. and Shizawa, K. ( 2002). A Thermomechanical Modeling and Simulation of Viscoplastic Large Deformation Behavior for Polymeric Materials: 2nd Report, Vertex Model Based on Flow Rule and its Finite Element Analysis, Trans. Jap. Soc. Mech. Eng. A, 68: 682-689 (in Japanese).

11.

Murakami, S. and Ohno, N. ( 1981). A Continuum Theory of Creep and Creep Damage, In: Creep in Structures, Springer-Verlag , Berlin, pp. 422-444.

12.

Nishikawa, M. ( 2008). Multiscale Modeling for the Microscopic Damage and Fracture of Fiber-reinforced Plastic Composites. Doctor Thesis, The University of Tokyo (in Japanese).

13.

Nishikawa, M. , Okabe, T. and Takeda, N. ( 2009). Periodic-cell Simulations for the Microscopic Damage and Strength Properties of Discontinuous Carbon Fiber-reinforced Plastic Composites , Adv. Compos. Mater., 18: 77-93.

14.

Ohno, N. , Okumura, D. and Noguchi, H. ( 2001). Microscopic Symmetric Bifurcation Analysis for Cellular Solids Based on a Homogenization Theory of Finite Deformation: 1st Report , Theory, Trans. Jap. Soc. Mech. Eng. A, 67: 618-624 (in Japanese).

15.

Okabe, T. , Nishikawa, M. , Takeda, N. and Sekine, H. ( 2006). Effect of Matrix Hardening on Tensile Strength of Alumina Fiber-Reinforced Aluminum Matrix Composites, Acta Mater., 54: 2557-2566.

16.

Okabe, T. and Takeda, N. ( 2001). Estimation of Strength Distribution for a Fiber Embedded in a Single-Fiber Composite: Experiments and Statistical Simulation Based on The Elastic-Plastic Shear-Lag Approach, Compos. Sci. Technol. , 61: 1789-1800.

17.

Okabe, T. and Takeda, N. ( 2002). Elastoplastic Shear-Lag Analysis of Single-Fiber Composites and Strength Prediction of Unidirectional Multi-Fiber Composites, Composites A, 33: 1327-1335.

18.

Takao, Y. , Taya, M. and Chou, T.W. ( 1982). Effects of Fiber-End Cracks on The Stiffness of Aligned Short-Fiber Composites, Int. J. Solid. Struct., 18: 723-728.

19.

Tohgo, K. and Chou, T.W. ( 1995). Incremental Theory of Particulate-Reinforced Composites Including Debonding Damage, Trans. Jap. Soc. Mech. Eng. A , 61: 382-388 (in Japanese).