Assessment of material crack resistance on the basis of measuring elastic strain energy

A new approach to determination of the crack resistance parameters is proposed as well as a testing method requiring no strictly standard conditions. The main point of the approach consists in measuring the reserves of elastic strain energy of a sample at the beginning and in the end of unstable fracture. The crack resistance has been assessed from the difference in the determined energies divided by the unstable fracture area. The results of testing 30KhMA-, 35KhMFA- and 20KhGNR steels with the use of this technique are presented. Comparison with the fracture toughness test results has shown that the brittle fracture parameters, as determined according to the suggested method, have convergence to the parameter of linear fracture mechanics