The prediction of failure envelopes and stress/strain behavior of composite laminates: comparison with experimental results

Two theoretical models were used by Sun and Tao [Comp. Sci. Technol. 58 (1998) 1125] in Part A of the exercise to predict the strength and stress/strain curves for a number of test problems. The strength model was based on linear elasticity in conjunction with a ply-discount method using parallel spring stiffness reduction, and the stress/strain curves were predicted by the linear model and a non-linear model incorporating simplified shear-lag analysis and an ABAQUS finite-element package. This paper provides a description of the correlation between experimental results provided by the organizers of the ‘failure exercise’ and the theoretical predictions, published in Part A for (a) biaxial failure envelopes of [0°] unidirectional and [0°/±45°/90°]s, [±30°/90°]s and [±55°]s multi-layered composite laminates, and (b) stress/strain curves for [0°/±45°/90°]s, [±55°]s, [0°/90°]s and [±45°]s under uniaxial and biaxial loadings.