Comparison of Damage and Undamaged Mechanical Structure using free vibration Analysis

Abstract

The current paper is about an experimental study of a free vibration and response of a mechanical structure. The comparison is drawn by showing the response of an undamaged and damaged mechanical structure. Damages are detected by analyzing the dynamic response of the structure. Vibration patterns of a damaged structure are different from the undamaged structure. First vibration pattern of an undamaged structure is analyzed and recorded. Then vibration pattern of a damaged structure is recorded, both of the patterns are compared to find out the intensity of damage caused by vibration. Three depth cases for crack are considered. Crack with 10mm, 20mm, and 30mm depth respectively. Transducers (accelerometers) record the data of the vibrating structure. The free vibration is given to the structure by striking the structure with a hammer to record the data. The natural frequency tends to get reduced as the crack depth increases Common frequencies assume an essential part in the damage recognition. The frequency of a damaged structure is lowered by reduction of stiffness and material degradation. With the help of vibration patterns and change in natural frequencies, it is easy to monitor the health of the structure and to detect the damage at the right time, in order to take safety precautions before the structure goes to failure.