چكيده به لاتين
Abstract
From the past, rotating machines play an important role in the industry; therefore, research in the field of rotor dynamics is essential for the advancement of the industry. One of the important issues in rotor dynamics is the behavior of the joints, which greatly affects the dynamics of the rotor. One of the most commonly used joints, which most rotors are assembled with, is shrink fitted joint. In this research, simulation of shrink fitted joint behavior was carried out using ANSYS software. A two-stage compressor rotor, with all parts assembled by shrink fit, was selected for study. The exact drawing of the shafts and impellers was done with AutoCAD to increase accuracy of calculations of the tension. To model this type of joint, a virtual layer with a density of 0.5 kg / m³, with a thickness of 0.5 mm, that have stiffness and structural damping, was considered to play the role of the joint. In this research, point mass, spring and damper were used to simulate the bearing and pedestal parameters. Since the shrink fitted joint is accompanied by stress on the coupling region, static analysis was performed in two steps before harmonic analysis was performed. In the first step, the stress due to contact was calculated using contact elements, and in the second step, the stress was induced by centrifugal forces. Further, the rotor with a modified stiffness caused by pre-stress, underwent the harmonic analysis under rotating unbalance in three different planes, phase and magnitude of the velocity were calculated in the pedestals. Then, the model updated using ANSYS software optimization tool to match the experimental data and indentify properties of the virtual layer and contact elements.
Keywords: Rotordynamics, Shrink-fitted joint, Hysteretic damping, Finite Element Method, ANSYS
