BSN Murthy¹, J. Srinivas², Ravi Pratap Singh^2,, K. Udaya Sri³, LSNVP Kiran¹

This paper deals the dynamic analysis of a flexible low-speed rotor model having both rotational asymmetries and transverse shaft cracks. Asymmetric disks or transverse shaft cracks in rotors lead to parametric inertia (or stiffness) excitations in rotor-bearing system. When both of them appear in a rotor system, prediction of parametric instability behavior has not gained sufficient attention. Disk asymmetry is considered in terms of the mass and damping terms and shaft stiffness is dictated by the transverse crack location and depth. The rotor is discretized into five elements and the resultant double periodic problem is solved using explicit Runge-Kutta time integration scheme. The specialty of the problem is that in every time step of integration, an assembled stiffness and mass matrix is formulated. The resulting five coupled nonlinear second-order system of equations are solved and the unbalance response of the rotor is obtained under various conditions of relative disk asymmetries and crack depth ratio. The present outcomes can be employed for identification of the rotor system from the vibration response.

double disk rotor, Asymmetric disk, Transverse open-crack, parametric excitation