A Nonlinear Energy Analysis for Cracked Lamina of Fibre-Reinforced Composite Material

The general G-K relation has been obtained and the nonlinear energy method generalized to analyzing the mixed mode fracture problem by W. Shen and James D. Lee. For the special case in which the line crack is perpendicular to one of the major loading axes, it has been found that the linear energy release rate is independent of the biaxial load factor while the nonlinear energy rate depends on it. In this paper, based on the nonlinear energy method for mixed mode fracture, the calculations for the pro cess of the nonlinear rate of off-axis cracked lamina of composite material subjected to biaxial loading have been performed. In addition, several examples have been given to explain the influence of fiber-orientation, biaxial loading factor and how the nonlinear correction factors vary with changes of the applied load.