Study On Coupled Vibration Characteristics Of Turbine Engine Bladed Disc System

The turbine engine is often used for the engine of airplane, large scale ship craft and vehicle. In recent years, it is also applied in power generation. Since 1940s, the appearance of turbojet engine, which has not only raised the speed and the height of plane, increased the flight of ship, but also has advanced the military might and brought vast financial profit. However, behind the rapid development of technique, there are still many problems restrict the technique to move forward a large step. Taking the bladed disc system as example, the working condition is so bad that it has to bear higher centrifugal load, aerodynamic load and vibration load, then the blade disc system is prone to be destroied. According to statistics, the error of bladed disc system vibration is more than half of total error that the engine generates. During the development of research of modern turbine engine, the optimization design of bladed disc system has caused coupled vibration between blade and disc, so more and more investigations have been done in this field.In this paper, taking the bladed disc system of turbine engine as object, the natural characteristic and the dynamic characteristic of bladed disc system is researched with the theory and simulation analysis.At the beginning, turbine disc is simplified to hollow circular plate, the continuous mass model of large deflection transverse bending of circular plate is built, and then the vibration characteristic of rotating circular plate is analyzed. Under a certain rotate speed, the mode of disc is calculated, and under different rotate speed, the vibration response is discussed, thereby, the influence of disc rotate speed on vibration response is obtained.Next, based on the method of finite element, the basic sector model of bladed disc is established, than beginning with the basic sector, the coupled vibration characteristics of the whole bladed disc system is investigated by combining both group theory algorithm and modal synthesis method.Finally, the vibration characteristics of bladed disc system were simulated and analyzed by general finite element program. Under different working condition, applying the theory of cyclic symmetry, the bladed disc system mode is analyzed, and the finite element component modal synthesis method was used to analyze bladed disc system, then the same model is researched by two different methods.The vibration laws of bladed disc system are obtained, it can provide a wider train of thought to research the vibration characteristics of turbine engine bladed disc system.