| Metallic materials are used in many applications because of their economy, strength and endurance limit. Fatigue damage may increase the risk of failure under cyclic load. Energy dissipation, termed damping, occurs in engineering metals as a function of the cyclic loading history.; Damping behavior of materials has been estimated using many different experimental techniques, and parameters i.e., the loss factor versus strain amplitude, frequency range, etc. However, micro-structural changes (fatigue damage) are also major contributors of failure or fracture in engineering materials. In order to measure energy dissipation, a damping monitoring method, which estimates the damping factor by vibration excitation, has been developed. Under a constant cyclic load, the effects of the number of fatigue cycles on the damping factor were studied for five different engineering metals. Experimental results show that the damping factor changes with the number of fatigue cycles. In addition, cyclic hardening, cyclic softening, and catastrophic failure effect the damping factor. |
