The mechanisms of energy dissipation in the non-propagating fatigue cracks in metallic materials

In a result of experimental investigations of titanium alloy VT-18U and alloy steel 15H2N specimens with an edge fatigue crack of mode I at bending vibrations it was revealed that the energy dissipation in a non-propagating crack is caused mainly by the elasto-plastic area around the crack tip and practically is not related to the friction between the crack surfaces. The level of energy dissipation in a crack is determined uniquely as a function of the cyclic (nominal) stress intensity factor range and is not effected by the initial level of damping of an intact specimen. unction can be used for the prediction of damping change caused by the crack initiation and growth and for the diagnostics of damage based on the prediction of damping change.