Thermal fracture characteristics of an interface crack subjected to temperature variations

Thermal fracture characteristics – the thermal energy release rate and thermal stress intensity factor of a semi-infinite crack at an interface between the two elastic isotropic materials, subjected to the temperature variations, are considered in this paper. Those characteristics are determined based on application of the linear elastic fracture mechanics (LEFM) concept. Expressions for obtained theoretical solutions are compared to solutions from literature and they are found to be more concise. Influence of the materials change on these two thermal fracture properties were observed, as well as the influence of the thickness ratio of the two layers constituting the interface.

Fracture of a Finite Medium with a Circular Internal Crack under Hyperbolic Heat Conduction-Prescribed Crack Face Temperature

This paper studies the fracture mechanics of a thermoelastic material layer with an internal crack subjecting to a prescribed temperature. The hyperbolic heat conduction theory is used and the transient thermal stress intensity factor is obtained. Comparisons of the results from the non-Fourier model and the Fourier model are made. The results demonstrate that the non-Fourier effect has a strong effect on the transient thermal stress around the crack tip. Thermal stress intensity factor predicted by the hyperbolic heat conduction model is considerably high then that predicted by the classical Fourier.

Fracture of a Finite Medium with a Circular Internal Crack under Hyperbolic Heat Conduction-Prescribed Crack Face Thermal Flux

This paper studies the fracture mechanics of a thermoelastic medium with an internal circular crack subjecting to a prescribed thermal flux. The time varying crack tip thermal stress intensity factor is solved. Solution for the infinite medium under steady heat conduction is given in closed form. Comparisons between the non-Fourier results and the classical Fourier results are made. Numerical results show that the non-Fourier heat model predicts considerable high transient thermal stress intensity factor than the Fourier model. This paper, together with our previous paper entitled fracture of a finite medium with a circular internal crack under hyperbolic heat conduction-prescribed crack face temperature, completes the analysis of a finite medium with a circular internal crack under hyperbolic heat conduction.

Understanding the Enhancement of Coating's Thermal Cracking Resistance by Multiple Segmentation

In this paper, the thermal shock induced cracking behavior of a segmented coating on the outer surface of a hollow cylinder has been investigated. The driving force for the propagation of multiple segmentation crack, represented by the Thermal Stress Intensity Factor (TSIF), was determined by combination of the principle of superposition and the finite element method. The maximum TSIF has been shown to occur neither at the beginning nor at the steady state of thermal transients, but at an intermediate instant. As the spacing between multiple segmentation cracks decreases, the magnitude of TSIF first plateaus, and then decreases sharply. This quantitative mechanistic result rationalizes the experimental observations that a segmented coating can exhibit much higher thermal shock resistance than an intact counterpart, if only the segmentation crack spacing is narrow enough. Some other parameters affecting TSIF, such as segmentation crack depth and convection severity, were also discussed.