Experimental model of fracture of functionally graded materials

Fabrication of functionally graded materials (FGM) can be obtained by layered mixing of two materials of different thermo-mechanical properties with different volume ratios gradually changing from layer to layer such that the first layer has only a few particles of the second phase and the last has the maximum volume ratio of the first phase.

Consider a simple model of the functionally graded materials as a multi-layered beam bonded to planes having shear modulus $ G_i$ and Poisson's ratio $ \nu_I$, respectively, subjected to bending. The behaviour of cracks depends on cracks configuration, size, orientation, material properties, and loading characteristic. The fracture mechanics problem will be approached by making use of photoelastic visualisation of fracture events in the model structure.