Investigation of the stability of a composite in compression along two parallel structural cracks at the layer interfaces

Composite construction materials with a layered structure may have various imperfections in the interlayer adhesion due to the technology used for their manufacture or their service conditions. In particular, this may involve defects of the crack type. Upon compression along such defects, the classical criteria for fracture (Griffith-Irwin or its generalization) cannot be used, since in this situation all the stress intensity factors and the openings of the sides of the crack are equal to zero, the onset of the process of fracture of the composite upon compression along cracks was hypothesized to be connected with loss of stability (buckling) in the vicinity of the crack. In investigation of the stability of a composite with cracks, different applied calculation schemes have been used by different authors: rod, shell, etc., and also approximate theories such as (for example) continuum theory. And within the framework of the latter, we cannot distinguish between interlayer and intralayer cracks. In this paper, within an exact formulation we consider the stability of a composite in compression along two parallel structural cracks located at the layer interfaces