DYNAMIC ANALYSIS OF MULTI CRACKED ROTOR THROUGH EXTENDED LAGRANGIAN MECHANICS

Cracked rotor diagnostics and the study of their dynamic behavior have made significant strides in recent years. While there are a number of research on singlecracked rotor systems, the problem of multiple-cracked rotor systems has received very less attention in the literature. The implications of crack depth, crack location, and shaft rotation speed on the nonlinear dynamic behavior of a multi-cracked rotor system are considered experimentally and analytically in this study. Umbra Lagrangian formalism is used to analyze the dynamic behavior of a multi-cracked rotor system, which is a novel expansion of the Lagrangian approach. The experimental analysis considers the impact of fracture depth on the shaft's stiffness and natural frequencies. We have used a vibration analyzer and a static impact hammer test to determine the resonant frequencies. The dynamic behavior of a rotor with a breathing crack has also been analyzed using OROS, a data collecting system. The existence of the second fracture has been seen to enhance the stress concentration along the first crack. The dominance of one crack over the other in determining the mode shapes and the speed restrictions is another intriguing occurrence. The research has been performed on a symmetrical system consisting of a pair of self-aligned double groove high speed bearings and a mild steel shaft. The analytical findings might provide more support to the experimental findings.