480-485Metallic
materials are used in many applications because of their economy, strength and endurance
limit. Fatigue damage is major contributor to failure or fracture in engineering
materials.Energy dissipation, termed damping, occurs in engineering metals as a
function of the cyclic loading hi story. Damping behaviour of materials has been
estimated using many different experimental techniques, and parameters, i.e., the
loss factor versus strain amplitude and frequency range. In order to measure energy
dissipation, a damping monitoring method, which estimates the damping factor by vibration excitation,
is used in this study.Under a constant cyclic load for high cycle fatigue, the effects
of the number of fatigue cycles on damping are studied in 304 stainless steel. An
empirical equation has been developed for constant energy increase per cycle up
to fatigue crack initiation. Experimental and analytical results are compared. Besides
small differences depending on some factors both values are in agreement