ON THE LIMITING RATES OF FRACTURE

The process of fracture is considered from the energy point of view, with the energy required for the radiation of acoustic waves in the course of formation and development of cracks being taken into account. It is shown that the radiation of acoustic waves by a crack is the major factor to be taken into account when analyzing the existence of the limiting fracture rates. To this end, a physical model of the crack growth process is developed which permits one to determine the parameters of the fields of the acoustic waves. An appropriate software for numerical calculations is created. A technique is suggested for estimation of possible rates of growth of the crack depending on the level of the preliminary loading. The limiting crack growth rate in transformer steel is estimated.