Trapping of a crack advancing through an elastic lattice

The paper presents the model of trapping of a crack within an elastic lattice in two loading configurations, which correspond to different types of engineering applications. First, the model of thermal striping of a continuum slab, containing a Mode I edge crack, under temporally sinusoidal thermal loading is extended to the situation when the continuum is replaced with a uniform triangular lattice. It is shown that in quasi-static growth, the crack advance is influenced by the micro-structure. In the homogenisation approximation, the stress intensity factor in the continuum elastic block is greater than the analogous value for the crack in the lattice. Furthermore, dynamic effects are investigated for the configuration when the size of the lattice cell is comparable with the wavelength of elastic waves generated by an external load. A nonlinear model of dynamic fracture is analysed for a crack advancing in a non-uniform triangular lattice. A comparison is made with a solution of the linearised problem to assess the average speed of the propagating crack.