连接件松动的非同步振动响应特征分析与验证  

ASYNCHRONOUS VIBRATION RESPONSE CHARACTERISTICS OF CONNECTORS WITH LOOSENESS FAULT AND ITS VERIFICATION

作　　者：王海飞[1] 陈果[1] 

机构地区：[1]南京航空航天大学民航学院,南京210016

出　　处：《工程力学》2016年第4期225-232,共8页Engineering Mechanics

基　　金：国家安全重大基础研究项目(613139);江苏省研究生培养创新工程项目(KYLX_0295);中央高校基本科研业务费专项资金项目

摘　　要：针对普遍存在的航空发动机连接件松动故障现象,建立了单自由度集总质量模型,引入松动故障模型,利用数值积分方法求得系统响应,分析了非同步响应特征;利用对含松动间隙的连接件进行松动实验,发现了其加速度响应经过自相关降噪后,时域波形表现为明显的冲击特征,波形上下不对称,呈现"截头状"波形;频谱上表现为伪临界亚谐共振以及伪临界超谐共振;此特征与仿真结果一致,可以作为判定松动故障的典型特征。通过仿真发现,导致连接件出现该松动特征的原因在于:1)松动故障引起的刚度的变化;2)当刚度变化的周期等于振动周期时,将产生倍频现象,在特定频率下,将激发系统的临界频率;当刚度变化的周期等于n倍振动周期时,则将产生1/n分频及其倍频,在特定频率下,将激发系统的临界频率。For the universal phenomenon of aero-engine connectors with looseness fault, a single degree of freedom lumped mass model was established and a looseness fault model was introduced. The response of the system was obtained by numerical integration methods and the asynchronous response characteristics are analyzed. The experiments were conducted on the connectors with looseness clearances. It is found that the acceleration response of a mass block after noise reduction has up-down asymmetrical impact characteristics in a waveform, also the pseudo-critical subharmonic resonance and the pseudo-critical ultra-harmonic resonance appear in a frequency spectrum. These characteristics are in an agreement with the results of the numerical simulation, which can be identified as the characteristics of looseness faults. The reason leading to the looseness characteristics is that the period of stiffness changes in the period of rotating speed. When the changing period of stiffness is equivalent to the vibration period, the frequency multiplication will appear and the critical frequency of the system will be excited at specific speeds. When the changing period of stiffness is equivalent to n times of the vibration period, 1/n frequency division and frequency multiplication will appear and the critical frequency of the system will be excited at specific speeds.

关 键 词：动力学模型 非同步响应特征 自相关降噪 松动故障 松动特征 

分 类 号：V231.9[航空宇航科学与技术—航空宇航推进理论与工程]