共查询到18条相似文献,搜索用时 578 毫秒
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一种确定非线性裂纹转子解的形式的新方法 总被引:3,自引:0,他引:3
将小波变换与Poincare映射相结合,即用Poincare映射确定周期解,用谐波小波变换区分拟周期响应和混沌运动,提出了一种分析非线性裂纹转子系统解的形式随参数变化的新方法.结果表明这种方法是非常有效的,它比以前所用的计算Liapunov指数的方法节约了计算时间,并且较易实施. 相似文献
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不连续机械系统混沌运动的控制 总被引:3,自引:1,他引:3
首先指出:预紧弹性约束,干摩擦等不连续力学因素将导致系统Poincare映射在控制目标附近不可微,故OGY等控制策略无法胜任这类系统的混沌运动控制。为控制这类系统的混沌运动,提出了由实验数据区分所合Poincare映射以及分区进行极点配置形成控制策略。对具有预紧弹性约束的受迫振子的仿真实验表明,这种控制策略是成功的。 相似文献
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本文讨论了无力矩条件下带有质量偏心轴对称转子的非对称陀螺体的运动。利用动量变量列写动力学方程,并将系统化作受周期微扰作用下的Euler-Poinsot运动。应用Melnikov方法预测系统存在Smald马蹄意义下的混沌运动,此结论与Poincare截面的数值计算相符。从Poincare截面的相图也可明显看出转子对于双自旋卫星的姿态稳定作用。 相似文献
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非线性系统全局动态特性分析的PCM法及其在转子轴承系统中的应用 总被引:8,自引:3,他引:8
本文将Poincare映射的思想与胞映射法相结合,提出了可用于高维非线性动力系统全局稳定性分析的新型数值方法:PCM(Poincare-Cell-Mapping)法,和胞映射法相比,新方法在实用上具有明显的优点。为说明PCM法的有效性,本文应用此方法对平衡转子轴承非线性动力系统进行了全局稳定性分析,同时给出了一确定状态空间中存在的所有周期解及其吸引域。 相似文献
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一类刚性约束转子碰摩的非光滑分析 总被引:2,自引:0,他引:2
本文建立并研究了一类与定子几何不对中的转子刚性碰摩模型,通过建立碰摩映射,将对不连续流非光滑系统的研究转化为对映射的研究。文中从几何角度分析了转子碰摩的机理并用数值方法得取了该类子碰摩的分岔和混沌等非一性结果。 相似文献
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具有裂纹-碰摩耦合故障转子-轴承系统的动力学研究 总被引:9,自引:0,他引:9
以非线性动力学和转子动力学理论为基础,分析了带有碰摩和裂纹耦合故障的弹性转子系统的复杂运动,在考虑轴承油膜力的同时构造了含有裂纹和碰摩故障转子系统的动力学模型。针对短轴承油膜力和碰摩-裂纹转子系统的强非线性特点,采用Runge-Kutta法对该系统由碰摩和裂纹耦合故障导致的非线性动力学行为进行了数值仿真研究,发现该类碰摩转子系统在运行过程中存在周期运动、拟周期运动和混沌运动等丰富的非线性现象,该研究结果为转子-轴承系统故障诊断、动态设计和安全运行提供理论参考。 相似文献
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分段线性系统动力学的非光滑分析 总被引:20,自引:4,他引:20
分析了分段线性系统的非光滑向量场对Poincare映射可微性的影响以及由此产生的复杂动力学行为.研究表明:当周期运动接近鞍结及其退化分叉或以很低速度穿过两线性区的切换面时,这类系统的动力学行为显著有别于具有光滑向量场的系统 相似文献
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强共振情况下冲击成型机的亚谐与Hopf分岔 总被引:4,自引:0,他引:4
通过理论分析与数值仿真研究了双质体冲击振动成型机的周期运动在强共振条件下的亚谐分岔与Hopf分岔,证实了此系统的1/1周期运动在强共振(λ0^4=1)条件下可以分岔为稳定的4/4周期运动及概周期运动.讨论了冲击映射的奇异性,分析了冲击振动系统的“擦边”运动对强共振条件下周期运动及全局分岔的影响。 相似文献
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Response analysis of a dual-disc rotor system with multi-unbalances–multi-fixed-point rubbing faults
Rotor unbalance and rub-impact are major concerns in rotating machinery. In order to study the dynamic characteristics of these machinery faults, a dual-disc rotor system capable of describing the mechanical vibration resulting from multi-unbalances and multi-fixed-point rub-impact faults is formulated using Euler beam element. The Lankarani–Nikravesh model is used to describe the nonlinear impact forces between discs and casing convex points, and the Coulomb model is applied to simulate the frictional characteristics. To predict the moment of rub-impact happening, a linear interpolation method is carried out in the numerical simulation. The coupling equations are numerically solved using a combination of the linear interpolation method and the Runge–Kutta method. Then, the dynamic behaviours of the rotor system are analysed by the bifurcation diagram, whirl orbit, Poincaré map and spectrum plot. The effects of rotating speed, phase difference of unbalances, convex point of casing and initial clearance on the responses are investigated in detail. The numerical results reveal that a variety of motion types are found, such as periodic, multi-periodic and quasi-periodic motions. Moreover, the energy transfer between the compressor disc and the turbine disc occurs in the multi-fixed-point rubbing faults. Compared with the parameters of the turbine disc, those of the compressor disc can affect the motion of the rotor system more significantly. That is, the responses exhibit simple 1T-periodic motion in the wide range of rotating speed under the conditions of sharp convex point and larger initial clearance. These forms of dynamic characteristics can be effectively used to diagnose the fixed-point rub-impact faults. 相似文献
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Leike Zhang Zhenyue Ma Bingwei Song 《Archive of Applied Mechanics (Ingenieur Archiv)》2013,83(6):817-830
Electromagnetic and mechanical forces are main reasons resulting in vibrations in hydraulic generating set. The non-symmetric air-gap between the rotor and stator creates an attraction force called unbalanced magnetic pull (UMP). The UMP can produce large oscillations which will be dangerous to the machines. In this paper, the nonlinear dynamic characteristics of a rotor-bearing system with rub-impact for hydraulic generating set under the UMP are studied. The rubbing model is established based on the classic impact theory. Through the numerical calculation, the excitation current, mass eccentricity, stiffness of shaft and radial stiffness of stator are used as control parameters to investigate their effect on the system, by means of bifurcation diagrams, Poincaré maps, trajectories and frequency spectrums. Various nonlinear phenomena including periodic, quasi-periodic and chaotic motions are observed. The results reveal that the UMP has significant influence in the response of the rotor system that the continuous increase in the excitation current induces the alternation of quasi-periodic and chaotic motions, the co-occurrence of oil whip and rub in a wide excitation range aggravates the vibration and leads to the instability of the system. In addition, the large eccentricity and radial stiffness of stator, as well as the small stiffness of shaft may lead to the occurrence of full annular rubbing while increasing the stiffness of the shaft can play an important role of suppressing the chaotic motion, reducing the vibration and improving stability of the system. 相似文献
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An impact oscillator is a non-smooth dynamical system with discontinuous state jumps whose dynamical behavior illustrates a variety of non-linear phenomena including a grazing bifurcation. This specific phenomenon is difficult to analyze because it coincides with an infinite stretching of the phase space in the neighborhood of the grazing orbit, resulting in the well-known problem of the square-root singularity of the Jacobian of the discrete-time map. A?novel Takagi?CSugeno fuzzy model-based approach is presented in this paper to model a hard impacting system as a non-smooth dynamical system including discontinuous jumps. Employing non-smooth Lyapunov theory, the structural stability of the system is analyzed to predict the onset of the destabilizing chaotic behavior. The proposed stability results, formulated as a Linear Matrix Inequality (LMI) problem, demonstrate how the new method can detect the loss of stability just before the grazing bifurcation. 相似文献
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