Cracking patterns in metal-ceramic laminates: Effects of plasticity

• Published in: Journal of the mechanics and physics of solids 1996-05, Vol.44 (5), p.801,813-811,821
• Main Authors: Shaw, M.C., Clyne, T.W., Cocks, A.C.F., Fleck, N.A., Pateras, S.K.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physics
• ISSN: 0022-5096
• DOI: 10.1016/0022-5096(96)00024-5

Multilayered metal-ceramic composites exhibit unique fracture characteristics that result from the need to reinitiate cracks in adjacent ceramic layers across intact metal layers. Quantitative knowledge of the stress and strain fields around cracked brittle layers is required to predict the fracture modes of such composites. In this paper, two competing fracture modes are analysed for a laminate containing a precrack that spans several layers: fracture is either by co-planar crack growth within the ceramic layers ahead of the initial crack, or, by multiple cracking within the ceramic layers. The appropriate boundary conditions employed in the numerical modelling are determined by comparing finite element predictions with experimental observations of elastic and plastic strain distributions around single cracks in Al Al 2O 3 laminates using moiré interferometry. It is found that plastic yielding of the metal layers encourages single, co-planar crack growth instead of multiple cracking. This competition between single and multiple cracking is summarised in the form of a fracture map.