基于整机耦合动力学模型的主轴承故障传递路径分析

Analysis on Fault Transmission Paths for Main Bearings Based on Coupling Dynamic Model of Whole Machine

针对航空发动机主轴承故障频发,亟需完善主轴承故障早期诊断的技术,开展了主轴承故障传递路径的研究,基于航空发动机整机耦合动力学模型,利用所建立的主轴承外圈剥落故障动力学模型,对该型航空发动机3^(#)和4^(#)支点的主轴承(中介轴承)外圈剥落故障进行动力学仿真并进行了故障特征分析。主轴承故障传递路径上各测点的特征频率表明:在航空发动机慢车、暖机和最大转速状态下,3^(#)支点轴承外圈剥落故障在轴承座和中介机匣测点上的故障特征均比较清晰,从轴承座到中介机匣测点的特征频率振动值分别衰减了99.5%,99.8%和99.7%,从中介机匣到进气机匣和涡轮机匣的振动值衰减则均不到90%;4^(#)支点中介轴承外圈剥落故障的特征频率几乎不能传递到机匣,难以从机匣测点中捕捉其故障特征频率。

In view of frequent faults of main bearings for aero-engines and the urgent need to realize early fault diagnosis of the bearings,the fault transmission paths for the bearings are studied.Based on coupling dynamic model of aero-engines,by using established dynamic model for spalling fault of outer rings of the bearings,the dynamic simulation of spalling fault of outer rings of main bearings(intermediate bearings)at fulcrums 3^(#)and 4^(#)of aero-engines is carried out,and the fault characteristics are analyzed.The characteristic frequency of each measuring point on fault transmission paths for the bearings shows that under the conditions of idle,warming-up and maximum speed of aero-engines,the spalling fault of outer rings of the bearings at fulcrum 3^(#)has relatively clear fault characteristics at measuring points of bearing housing and intermediate casing,and the characteristic frequency vibration values of measuring points from bearing housing to intermediate casing are attenuated by 99.5%,99.8% and 99.7% respectively,the vibration attenuation from intermediate casing to air intake casing and turbine casing is less than 90%;the characteristic frequency of spalling fault of outer rings of intermediate bearings at fulcrum 4^(#)can hardly be transmitted to casing,making it difficult to capture the fault characteristic frequency from measuring points of casing.