Fracture of layered composites by internal fibre instability: Effect of interfacial adhesion

In this paper, a mechanism of compressive fracture for elastic and elastic-plastic composite materials with interfacial adhesion defects is investigated. A classification of different approaches in modelling compressive response of layered materials is given. The analysis finds the tipper and the lower bounds for the critical load. In order to achieve this, the problem of the internal fibre (layer) instability is considered within the scope of the exact statement based on the application of the model of a piecewise-homogeneous medium and the equations of the three-dimensional (3D) stability theory. The solution of the 3D problem is found for the most general case accounting for the bi-axiality of compressive loads. The characteristic determinants are derived for the first four fibre instability (microbuckling) modes, which are more commonly observed. Special attention is given to the calculation of critical loads for practical elastic and elastic-plastic layered materials.