Temperature induced crack propagation in structured media

This paper describes the propagation of an edge crack in a semi-infinite triangular lattice, consisting of identical point masses connected by thermoelastic links. A change of temperature, represented by a time-periodic series of high-gradient temperature pulses, is applied at the boundary of the lattice. In order to make the initial crack advance in the lattice a failure criterion is imposed, whereby the links break as soon as they attain a prescribed elongation. The elongations of the links are produced both by variation in temperature and by the elastic waves generated at the boundary due to thermal shocks. The nonlinear simulations presented in this paper show that the average speed of crack propagation can be estimated from the dispersion curves of the lattice. Temperature and inertia contributions to crack propagation are also investigated. The results of this investigation show that the crack in the lattice stops at a certain distance from the boundary, and this distance depends on the frequency and amplitude of the applied temperature and on the threshold elongation. In addition, it is found that inertia amplifies the elongations of the links, and thus the crack advances further into the lattice if inertial effects are present.

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