Vibration Analysis of Rotating Shaft with Longitudinal Crack

Rotating shafts which are subjected to the hardest conditions in high performance rotating equipments used in the process and utility plants like high speed compressors, steam and gas turbines, generators and pumps and in industrial machines etc. Although when shafts are operated in different type of conditions then serious defects can appear, but these are much suspected to fatigue cracks because of the rapidly fluctuating nature of bending stresses. Because of manufacturing flaws or cyclic loading, cracks frequently appear in rotating shaft, other defects in shafts include bent shaft, misalignment etc. The tensile stress concentration resulting from shear slip causes the new cracks that propagate away from the pre-existing fault. Due to crack on shaft catastrophic failure, machine can be damage, it is hazards to human being, accident will be occur etc. A defect on shaft can be diagnosed by many methods, e.g., ultrasonic detection, electromagnetic method, acoustic emission, vibration analysis. We use vibration analysis method because when shaft rotates then due to defect the vibrational response of the rotating shaft will more or less change. By using the additional vibration extracted from the shaft response due to defect, an on-line condition monitoring system for defect detection might be developed for rotor systems. Other methods of crack detection are time consuming and it does not give proper result that?s why we use vibration analysis method.