Cracked shaft detection rig

Abstract

The ever-growing interest of the modern-day rotor dynamicist in the early detection of rotor cracks in turbomachinery has been the direct result of multiple catastrophic experiences that industry has had to face in recent times due to cracked rotors. The complete failure of the rotor due to crack propagation is easily recognized as one of the most serious modes of plant failure. Even so, this aspect has without question not received the attention it warrants. The last decade has, however, witnessed some laudable attempts that have been moderately successful in detecting cracked rotors. This work presents the design and set-up of a complete test rig that can be used for experimental research on response characteristics of cracked rotors. The results of this research will permit increased confidence in detecting the presence of rotor cracks in turbomachinery.

The designed rig is capable of testing cracked shafts under the effect of lateral and coupled lateral-torsional vibrations. The conventional vibration signature analysis approach has been employed for the purpose of test rig evaluation and condition monitoring. The test rig has been shown to be essentially functional and the experimental data generated with the test rig are compared to appropriate analyses and published results.