转子系统不对中—裂纹耦合故障的非线性动力学分析

发布时间：2018-06-14 17:11

本文选题：转子系统 + 联轴器　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：旋转机械是在工业部门中应用最为广泛的一类机械设备,它的稳定运行影响着整个工业的发展进程。而转子系统作为旋转机械的核心部件,它的动力学特性直接影响着旋转机械的结构安全和工作性能。由于转子系统运行环境的恶劣,在实际工程作业中转子系统发生耦合故障是非常常见的,因此转子系统的耦合故障是转子系统非线性动力学研究的重要内容之一。不对中和裂纹故障都是转子系统常见的故障,当转子系统在不对中状态下运行时可能引起转轴挠曲大变形和转轴磨损,大大增加了转轴上出现裂纹或使转轴上原有的小裂纹加深的可能性;而含较深裂纹的转子系统会使系统的响应过大导致不对中故障。因此,本文以某航空发动机低压转子系统为研究对象,对转子系统不对中-裂纹耦合故障的非线性动力学特性进行了研究。首先分析了齿式联轴器在不对中状态下的运动规律,推导出了联轴器平行角度不对中的激振力;比较了裂纹常用的数学模型的优缺点,选取了最适合的裂纹模型;对起支撑作用的滚动轴承进行了运动分析和载荷分析;利用拉格朗日建模法建立了转子系统不对中-裂纹耦合故障的动力学微分方程,并对其进行了无量纲化。随后运用四阶Rugge-Kutta法对该系统进行了仿真分析,得到了不对中、裂纹单一故障和不对中-裂纹耦合故障的动力学特性。当转子系统只有联轴器不对中故障时,系统响应出现了1倍频和2倍频,转子系统不仅在临界转速处出现1倍频共振,而且在二分之一临界转速处出现2倍频共振;当转子系统只有裂纹故障时,系统响应出现了1倍频、2倍频、3倍频等高频成分,在临界转速、二分之一临界转速和三分之一临界转速处出现了振动峰值,并且二分之一临界转速处的振动幅值与三分之一临界转速处的振动幅值相近。转子系统同时出现不对中和裂纹故障时,系统响应具有1倍频、2倍频、3倍频等高频成分,在临界转速、二分之一临界转速和三分之一临界转速出现振动峰值,并且二分之一临界转速处的振动峰值要远远高于三分之一处的临界转速。最后利用分岔图、Poincaré截面图、时域波形图、幅值谱图分析了含不对中-裂纹耦合故障的转子系统参数对耦合故障系统响应的影响。
[Abstract]:Rotating machinery is the most widely used mechanical equipment in the industrial sector, and its stable operation affects the development process of the whole industry. As the core component of rotating machinery, the dynamic characteristics of rotor system directly affect the structural safety and performance of rotating machinery. Because of the bad operating environment of rotor system, coupling faults of rotor system are very common in practical engineering, so coupling fault of rotor system is one of the important contents of nonlinear dynamics research of rotor system. Misalignment and crack faults are common faults in rotor system. When the rotor system is running under the condition of misalignment, it may cause large deflection and wear of the shaft. It greatly increases the possibility of cracks on the shaft or deepening of the original small cracks on the shaft, while the response of the rotor system with deeper cracks will lead to misalignment fault. Therefore, in this paper, the nonlinear dynamic characteristics of an aero-engine low-pressure rotor system with mismatched mid-crack coupling faults are studied. Firstly, the motion law of gear coupling in misalignment state is analyzed, the exciting force in parallel angle misalignment of coupling is deduced, the advantages and disadvantages of common mathematical models of crack are compared, and the most suitable crack model is selected. The motion analysis and load analysis of rolling bearing are carried out, and the dynamic differential equation of coupling fault of rotor system is established by using Lagrangian modeling method, and it is dimensionless. Then the fourth order Rugge-Kutta method is used to simulate the system, and the dynamic characteristics of single fault and coupling fault are obtained. When the rotor system has only the misalignment fault of the coupling, the response of the rotor system is doubled frequency and 2 times frequency. The rotor system not only has 1 frequency doubling resonance at the critical speed, but also has 2 times frequency resonance at the 1/2 critical speed. When the rotor system has only a crack fault, the response of the rotor system has a high frequency component, such as 1 double frequency, 2 times frequency and 3 times frequency, and the vibration peak occurs at the critical speed, 1/2 critical speed and 1/3 critical speed. The vibration amplitude at 1/2 critical speed is similar to that at 1/3 critical speed. When the rotor system is not neutralized and cracked at the same time, the response of the rotor system has high frequency components, such as frequency doubling, frequency doubling and so on, and the vibration peak occurs at critical speed, 1/2 critical speed and 1/3 critical speed. And the peak value of vibration at 1/2 critical speed is much higher than that at 1/3. Finally, the effects of rotor system parameters on the response of coupled fault system are analyzed by using bifurcation diagram Poincar 茅 section, time-domain waveform diagram and amplitude spectrum diagram.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH165.3

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