Numerical study of the crack growth direction within a quasi-brittle material in a gradient temperature field

The elliptical crack growth in a quasi-brittle material located in a gradient field of temperature next to the melting temperature for the thermodynamic phases of the material is studied. The elastic properties of the material are assumed to have an obvious dependence on temperature. This is typical for materials located close to the melting point. To determine the direction of crack growth, a gradient strain criterion is introduced, which assumes crack growth from the point of maximum elastic strain of the material toward its minimum. Depending on the orientation of the crack axis relative to the direction of the temperature gradient, the crack retardation, the change of the crack growth direction, or the appearance of secondary lateral cracks in the vicinity of the main crack tip are possible. The calculated results and the admissibility of applying the introduced criterion have been successfully validated by an experiment with thermal fracture of freshwater ice blocks. As a result, the phenomena predicted by finite element calculations have also been discovered experimentally.