Damage accumulation in the pre-fracture zone under low-cyclic loading of specimens with the edge crack

The paper presents the results of experimental investigation of damage accumulation in the pre-fracture zone under low-cyclic loading, which is three-point bending of a beam with the transverse notch. The following materials are under study: aluminium alloys D16T and D16 AT, steels ST3, ST45, and 70G. As a measure of material damage, residual deflection of a beam is used. The description of regularity of damage accumulation by the use of inverse power functions is proposed. The basic parameter characterizing the resistance of material to fatigue damage has been determined. The effect of preliminary inelastic strain of material on its resistance to fatigue damage, as well as the effect of catastrophic overload of the material on its subsequent cyclic deformation at reduced loads is studied. The comparison between the experimental data obtained and the theoretical model are given.