Temperature effects crack propagation type

Two types of strength degradation are found during thermal shock. For materials in which crack propagation is unstable, there is a catastrophic decrease in strength at the critical temperature difference (Fig. 9.14). This effect becomes... 

A more subtle effect of temperature is also displayed in Fig. 17 where experiments [34] show a rapid increase of the adhesion energy with temperature, related to a change in the rupture mechanism from interfacial fracture by crack propagation to failure by fibrillation and debonding of the fibrils. The interpretation of the authors is that the temperature change is responsible for a modification of the adhesive-probe contact area, which, in turn, results into different types of rupture mechanisms in the two temperature ranges. 

A broad study of this test has been carried out by Blackman et al. (2000), who - on the basis of a series of tests carried out on several types of adhesives, at different speeds and temperatures, and using a high-speed hydraulic machine - have analyzed the effect of the specimen geometry and type of crack growth. The onset and the propagation of the rupture have been observed by means of high-speed photography. Furthermore, the authors have reviewed the methods proposed by the standard to extract the results and have applied a finite element model to reproduce the firacture of the specimen. 

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