Published Paper Details:

In Thermal power plants Rotating Equipment plays a vital role, the structural integrity of rotating machinery is critical for safe and efficient operation, Rotor lifetime and safety primarily depends on the level of rotor vibration. In order to avoid unwanted consequences for the plant due to rotor damage and to meet the highest requirements of design reliability, accurate rotor dynamic predictions are mandatory. Having the correct rotor model is critical issue in dynamics prediction. Often research activities are focused only on the rotor-bearing system analysis. However, generally the whole system, which includes the rotor, bearings, casing and structural supports should be considered. Special attention should be paid to the influence of structural supports which reveals when the rotor is supported with ball bearings because of low damping and high bearing stiffness. The approach presented in this paper allows to simulate the influence of structural supports on rotor dynamics response and as a result, the full picture of rotor-bearing-support system resonances can be analysed to avoid potential problems. The methodology is based on support vibrations modal reduction technics. According to the approach, the natural frequencies and their mode shapes should be calculated for the separate support structure applying a three dimensional finite element model and the relative displacements at bearing location points are measured. Supports' normalized model characteristics (model mass and model stiffness) for each vibration mode should then be imported in a rotor dynamics algorithm for rotor unbalance response analysis.