含裂纹转子系统动力学建模与实验研究

疲劳、材料缺陷等因素会导致转子出现不同程度的裂纹。为分析裂纹对转子系统动态特性的影响,本文建立了裂纹转子系统的刚度矩阵,并通过有限元仿真和ZT-3实验台开展了裂纹角度和转速对裂纹转子系统动态特性研究。结果表明：在不同角度的裂纹对转子动态特性的影响分析中,45°裂纹转子系统较30°裂纹转子系统的振动响应剧烈、范围大、轴心轨迹变形程度大,波形的频率叠加现象更为明显,更多的高倍频和分数倍频被激发；在转速为(2000rpm,4000rpm)范围内,随着转速的增加,系统的时域波形逐渐趋于平稳,频率叠加现象减少,振动范围逐渐扩大,轴心轨迹逐渐变为规则的椭圆形,在3200rpm附近存在着系统的临界转速；通过实验得出的裂纹转子系统动态特性与仿真结果吻合,验证了仿真的正确性。

Dynamic Modeling and Experimental Study of Cracked Rotor System

Fatigue, material defects and other factors can cause different degrees of cracking in the rotor. In order to analyze the influence of crack on the dynamic characteristics of the rotor system, the stiffness matrix of the cracked rotor system is established. The dynamic characteristics of the cracked rotor system were studied by finite element simulation and ZT-3 experimental bench. The results show that in the analysis of the influence of cracks at different angles on the dynamic characteristics of the rotor, the 45° cracked rotor system has a sharper vibration response than the 30° cracked rotor system, and the range is large, and the axial trajectory deformation is large. Obviously, more high frequency and fractional multiples are excited. In the range of speed (2000rpm, 4000rpm), as the speed increases, the time domain waveform of the system gradually becomes stable, the frequency superposition phenomenon decreases, the vibration range gradually expands, and the axis trajectory gradually becomes a regular ellipse at 3200 rpm. There is a critical speed of the system nearby. The dynamic characteristics of the cracked rotor system obtained by experiments are in good agreement with the simulation results, which verifies the correctness of the simulation.