A predictive framework has been developed by Wallin (1997). The predicted fracture toughness transition temperature shift, ΔT o (in °K) depends on loading rate, Κ (expressed as the rate of increase of the applied stress intensity factor in MPa √m/s), static fracture toughness transition temperature, T o stat (in °K for a loading rate, of Κ = 1MPa √m/s) and the static yield strength, σ ys (in MPa), as follows:
For a ratio of dynamic to static loading rate of 104, the predicted shifts are as shown in Fig.1. It can be seen that the shifts are a function of yield strength (with lower predicted shifts for higher yield strength), but also depend strongly on the absolute value of static fracture toughness transition temperature, with markedly lower predicted shifts for higher transition temperatures.
K Wallin: 'Effect of Strain Rate on the Fracture Toughness Reference Temperature, To, for Ferritic Steels', Proc. Conf. 'Recent Advances in Fracture' (R K Mahidhara, Ed), pp171-181, The Minerals, Metal and Materials Society of AIME, 1997.