The step fracture analysis based on the energy balance equation in integral form

The integral energy balance equation concept developed earlier [1–3] has been used to analyze the test results [5] obtained on compact tension and three-point bending specimens. This registered test data acquired in certain specimen material and loading conditions have a step appearance which clearly shows the sequence of separate events in a brittle fracture and simplify analysis of the process. The particularity of the data has been used to get better insight into the brittle fracture process and verify applicability of the equation describing plastic flow crack extension to certain stages of the process and to check the relevance of the plastic-brittle fracture transition criteria based on the energy balance equation in integral form or load intensity concept.