The nonlinear behavior of AS4/PEEK composite under off-axis loading was investigated using a finite element-based micromechanical approach with three different unit cells. Proper boundary conditions for uniaxial off-axis loading for the unit cell were established. The elastic moduli of the fiber and the nonlinear stress-strain curve of the matrix were used in the micromechanical analysis. By comparing the predicted off-axis stress-strain curves with experimental data, it was found that the nonlinear behavior of the composite is highly dependent on the fiber packing arrangement of the unit cell model.
References
1.
1. Adams, D.F. (1970). Inelastic Analysis of a Unidirectional Composite Subjected to Transverse Normal Loading , J. Composite Materials, 4: 310-328 .
2.
2. Adams, D.F. and Crane, D.A. (1984). Finite Element Micromechanical Analysis of a Unidirectional Composite Including Longitudinal Shear Loading , Computers and Structures, 18: 1153-1165 .
3.
3. Sun, C.T. and Vaidya, R.S. (1996). Prediction of Composite Properties From a Representative Volume Element , Composite Science and Technology, 56: 171-179 .
4.
4. Jansson, S. (1992). Homogenized Nonlinear Constitutive Properties and Local Stress Concentrations for Composites With Periodic Internal Structure , Int. J. Solids Structures, 29(7): 2181-2200 .
5.
5. Brockenbrough, J.R., Suresh, S. and Wienecke, H.A. (1991). Deformation of Metal-Matrix Composites With Continuous Fibers: Geometrical Effects of Fiber Distribution and Shape , Acta Metall. Mater., 39(5): 735-752 .
6.
6. Sun, C.T. and Chen, J.L. (1989A). Simple Flow Rule for Characterizing Nonlinear Behavior of Fiber Composites , J. Composite Materials, 23: 1009-1021 .
7.
7. Yoon, K.J. (1990). Characterization of Elastic-Plastic and Viscoplastic Behavior of AS4/PEEK Thermoplastic Composite for Temperature Variation, PhD Thesis, School of Aeronautics and Astronautics, Purdue University.
8.
8. Aboudi, J. (1991). Mechanics of Composite Materials: A Unified Micromechanical Approach, Elsevier, Amsterdam .
9.
9. Chen, J.K., Allahdadi, F.A. and Sun, C.T. (1997). A Quadratic Yield Function for Fiber-Reinforced Composites , J. Composite Materials, 31(8): 788-811 .
10.
10. Sung, K.H., Wang, Q. and Chang, F.K. (1991). Modeling the Viscoplastic Behavior of Fiber-Reinforced Thermoplastic Matrix Composites at Elevated Temperatures , J. of Composite Materials, 25: 334-373 .
