Fatigue analysis of metals using damping parameter

A methodology for evaluating fatigue life of metals in both low and high cycles using the material damping parameter is presented. While most techniques for evaluation of fatigue life suffer from different types of restrictions-e.g., limitations to low-cycle fatigue tests or restrictions to the applications where a measurable temperature rise is a prerequisite-damping measurements can be used without such limitations. The results of series of experiments are reported to illustrate how the damping parameter changes during the fatigue test. The validity of the concept is confirmed by comparing results with those obtained by measuring the hysteresis loop. Also presented are discussions on how damping measurements can be modified to investigate the effects of inhomogeneity of the material and the crack initiation due to cyclic fatigue damage.