碰摩叶片结构稳态响应分析

发布时间：2018-05-16 03:14

本文选题：旋转叶片 + 碰摩故障　；参考：《东北大学》2013年硕士论文

【摘要】：高速旋转叶片是旋转机械中的关键部件,在航空航天和机械工程领域中的应用都非常广泛。叶片在高速旋转时,主要承受的载荷为不稳定的气流激振力和高速旋转下产生的离心力。叶片与机匣之间的碰摩就成为了空气压缩机组中最常见的故障之一,通常会产生较大幅值的振动,导致系统产生非常复杂的非线性动力学行为,同时还会引起叶片疲劳、弯曲、折断等严重的失效行为,影响机组的安全稳定运行。本课题以透平式空气压缩机叶片为研究对象,从理论和数值方面研究了碰摩叶片结构的非线性动力学特性,对其稳态响应进行了分析计算。增量谐波平衡法作为求解非线性振动问题的定量方法之一,被广泛地应用于非线性振动的各个领域,成为求解非线性振动,特别是强非线性振动的有效方法。然而,其在求解完整多自由度局部非线性系统稳态响应时,会遇到耗时太长的问题,这极大地限制了其在高维局部非线性系统分析中的应用。因此,姚红良针对碰摩接触产生非线性的局部多自由度系统的非线性特性,提出了降维的增量谐波平衡法(DRIHB法)。本文基于此算法开展的主要研究内容如下：(1)基于增量谐波平衡法,提出了降维的增量谐波平衡法(DRIHB法)。通过谐波平衡理论分析了系统中各自由度各次谐波的定量对比关系,并且根据该定量对比关系使系统的维数降至与非线性自由度的个数相同。由于降维后系统为复数系统,本文给出了该类系统的求解方法,以及原系统各自由度各阶响应的还原方法。(2)应用本文算法分别计算了平板结构、叶片实体结构碰摩非线性振动系统的稳态周期解,得到了时域波形和频谱图,并通过与数值积分方法所得结果进行比较,验证了本文算法的精确性和时效性。同时做出了系统的各次谐波响应曲线,体现了该算法在分析复杂高维非线性振动问题时的优势。(3)针对大型空压机转子系统建立了有限元动力学模型,采用DRIHB法研究了该类复杂高维转子系统的强非线性振动问题。分析了系统在单点、两点、四点碰摩三种不同碰摩位置时的稳态响应；同时分析了接触刚度和碰摩间隙对系统响应的影响。
[Abstract]:High speed rotating vane is a key component in rotating machinery and is widely used in aerospace and mechanical engineering fields. When the blade rotates at high speed, the main load is unstable airflow excitation force and centrifugal force caused by high speed rotation. The rub-impact between the blade and the casing becomes one of the most common faults in the air compressor unit. It usually produces a large amplitude vibration, which leads to very complicated nonlinear dynamic behavior, and also causes the blade fatigue and bending. Serious failure behavior, such as breakage, affects the safe and stable operation of the unit. In this paper, the nonlinear dynamic characteristics of rub-impact blade structure are studied theoretically and numerically, and its steady state response is analyzed and calculated. As one of the quantitative methods for solving nonlinear vibration problems, incremental harmonic balance method has been widely used in various fields of nonlinear vibration, and has become an effective method for solving nonlinear vibration, especially for strong nonlinear vibration. However, when solving the steady-state response of complete multi-degree-of-freedom (MDOF) local nonlinear systems, it will meet the problem of long time consuming, which greatly limits its application in the analysis of high-dimensional local nonlinear systems. Therefore, Yao Hongliang proposed an incremental harmonic balance method to reduce the dimension of the nonlinear local multi-degree-of-freedom system caused by rub-impact contact. In this paper, the main research contents based on this algorithm are as follows: (1) based on the incremental harmonic balance method, a reduced-dimension incremental harmonic balance method is proposed. Based on the harmonic balance theory, the quantitative comparison relationship of each degree of freedom harmonics in the system is analyzed, and the dimension of the system is reduced to the same as the number of nonlinear degrees of freedom according to the quantitative comparison relationship. Since the system is a complex system after dimensionality reduction, this paper gives the solution method of the system and the method of reducing the response of each degree of freedom of the original system. (2) the flat plate structure is calculated by using the algorithm in this paper. The steady periodic solution of rub-impact nonlinear vibration system with blade structure is obtained, and the time-domain waveform and spectrum diagram are obtained. The accuracy and timeliness of the proposed algorithm are verified by comparing the results with the numerical integration method. At the same time, the harmonic response curves of the system are given, which shows the advantage of the algorithm in analyzing the complex high dimensional nonlinear vibration problem. The finite element dynamic model is established for the rotor system of the large air compressor. The DRIHB method is used to study the strong nonlinear vibration of this kind of complex high dimensional rotor system. The steady-state response of the system at three different rub-impact positions at single point, two point and four point is analyzed, and the influence of contact stiffness and rubbing clearance on the system response is also analyzed.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH45

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