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复杂非线性转子—轴承系统动力特性数值分析 总被引:3,自引:0,他引:3
研究非线性高维复杂转子-轴承系统的动力特性。针对系统的局部非线性特征,给出了一种降阶及配套动力积分方法。降阶系统仍保持局部非线性特征,非线性响应数值积分所需的迭代只需在局部非线性的维数上执行。对于油膜力无封闭解的实际轴承,采用变分不等方程有限元法求解Reynolds边值问题,使得油膜力及其Jacobian矩阵的计算变得非常简单明了且与具有协调一致的精度。应用上述方法计算分析了一双跨、椭圆轴承-转子系统的不平衡响应,数值结果展现了系统丰富复杂的非线性现象。 相似文献
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非线性转子动力学的稳定性和分岔 总被引:2,自引:0,他引:2
大型高速转子的工作转速往往超过其第一阶临界转速,咽而需要考虑系统的非线性刚度和转轴材料的内阻尼对轴振动特性的影响。本文研究非线性围各阶共振点(临界转速)时的稳定性,并应用奇异性理论拱皋地转轴的定常运动(同步涡动)和自激振动(非同步涡动)周期响应的分岔。本文的结论不仅揭示了非线性转子丰富的动力学形为,对对大型高速转子的稳定性控制有一定参考价值。 相似文献
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求解非线性振动问题的一种新方法 总被引:1,自引:0,他引:1
首先把描述非线性振动的微分方程归结为一非线性积分微分方程,然后把此积分微分方程的求解转化为一无穷阶的非线性代数方程组的求解。从理论上讲,可得到满足任何精度要求的周期解。本文用此方法对Dufing系统进行了分析。 相似文献
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转子—非线性支承系统振动响应的优化计算 总被引:1,自引:0,他引:1
本文用一种新的优化方案计算装有非线性弹性支承-挤压油膜阻尼器的转子系统的振动响应。首先根据转子系统的结构特点,建立其无量纲形式的非线性运动微分方程;然后由微分方程构造-控制目标函数,最后对此目标函数进行优化计算,求得转子系统的振动响应。 相似文献
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研究了单自由度非线性单边碰撞系统在窄带随机噪声激励下的次共振响应问题。用Zhuravlev变换将碰撞系统转化为速度连续的非碰撞系统,然后用随机平均法得到了关于慢变量的随机微分方程。在没有随机扰动情形,得到了系统响应幅值满足的代数方程;在有随机扰动的情形下,给出了系统响应稳态矩计算的迭代公式。讨论了系统阻尼项、非线性项、随机扰动项和碰撞恢复系数等参数对于系统响应的影响。理论计算和数值模拟表明,系统响应幅值将在激励频率接近于次共振频率时达到最大。而当激励频率逐渐偏离次共振频率时,系统响应迅速衰减。 相似文献
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本文提出了通过逐次将非线性力等效线性化,然后用具有许多优点的 Prohl 法计算等效系统响应的迭代法,用以求非线性转子系统的稳态不平衡响应.实例计算了装有中介轴挤压油膜阻尼器的双转子发动机的稳态不平衡响应. 相似文献
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质量任意分布下的柔性转子过临界点时的瞬态响应 总被引:1,自引:0,他引:1
本文首先将Riccati传递矩阵法和正、逆回旋运动分解理论应用于有阻尼的分布质量转子的复特征问题计算,求出系统各阶正、逆回旋临界速度(也称临界点)及相应振型然后作者对广义阻尼模态理论作了引伸和发展,结合Bogoliubov-Mitropolskii渐近法,建立起一阶微分方程组,计算不平衡柔性转子分别在正、逆回旋下通过各阶临界点的非线性、非定常瞬态响应,还深入分析了转子相继通过两十分邻近的临界点时发生的耦合现象。 相似文献
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Li Yuqi Luo Zhong Liu Zijia Hou Xiaojie 《Archive of Applied Mechanics (Ingenieur Archiv)》2019,89(11):2381-2395
Archive of Applied Mechanics - A dynamic model of the rotor-bearing system with bolted joint structure is set up based on the Lagrange’s equations, which considers the bearing clearance, the... 相似文献
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Cai-Wan Chang-Jian Her-Terng Yau 《Acta Mechanica Solida Sinica》2007,20(4):309-316
This study performs a dynamic analysis of a rotor supported by two squeeze couple stress fluid film journal bearings with nonlinear suspension.The numerical results show that the stability of the system varies with the non-dimensional speed ratios and the dimensionless parameter l*.It is found that the system is more stable with higher dimensionless parameter l*. Thus it can conclude that the rotor-bearing system lubricated with the couple stress fluid is more stable than that with the conventional Newtonian fluid.The modeling results thus obtained by using the method proposed in this paper can be used to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided. 相似文献
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非线性系统周期强迫不平衡响应的稳定性分析 总被引:4,自引:0,他引:4
多自由度强非线性系统是工程实际中经常遇见的一类模型,利用非线性动力学分析中的打靶法求解该类系统的周期解,并对Flopuet主导特征值判断周期解的失稳方式,利用该方法对旋转机械中的一个具体模型;双盘县臂柔性转子-非同心型挤压油膜阻尼器(SFD)系统周期强迫不平衡响应的稳定性和分岔行为进行了分析,分析表明,在该系统中存在着第二Hopf分岔、倍周期分岔、鞍-结分岔三种分岔形式。 相似文献
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To overcome the shortcomings of extreme time-consuming in solving the Reynolds equation, two efficient calculation methods,
based on the free boundary theory and variational principles for the unsteady nonlinear Reynolds equation in the condition
of Reynolds boundary, are presented in the paper. By employing the two mentioned methods, the nonlinear dynamic forces as
well as their Jacobians of the journal bearing can be calculated saving time but with the same accuracy. Of these two methods,
the one is called a Ritz model which manipulates the cavitation region by simply introducing a parameter to match the free
boundary condition and, as a result, a very simple approximate formulae of oil-film pressure is being obtained. The other
one is a one-dimensional FEM method which reduces the two-dimensional variational inequality to the one-dimensional algebraic
complementary equations, and then a direct method is being used to solve these complementary equations, without the need of
iterations, and the free boundary condition can be automatically satisfied. Meanwhile, a new order reduction method is contributed
to reduce the degrees of freedom of a complex rotor-bearing system. Thus the nonlinear behavior analysis of the rotor-bearing
system can be studied time-sparingly. The results in the paper show the high efficiency of the two methods as well as the
abundant nonlinear phenomenon of the system, compared with the results obtained by the usual numerical solution of the Reynolds
equation. 相似文献
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有效集法在数学规划加权残值法中的应用 总被引:1,自引:0,他引:1
本文研究有效集法在数学规划加权残值法求解微分方程问题中的应用。从理论上和实际应用方面 阐明,对于数学规划加权残值法和线性规划问题,有效集法比常用的单纯形法更简便、易程序化、计算速度更快,因此更适用于数学规划加权残值法求解微分方程问题。 相似文献
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非线性大挠度矩形板中内共振导致的分叉 总被引:21,自引:0,他引:21
研究了一个非线性大挠度矩形板在简谐激励作用下的动力学行为,利用Galerkin原理和平均法建立了这一非线性系统的双模态模型,讨论了由于内共振导致的分叉行为,最后利用数值分析证实了理论分析得到的结论。 相似文献
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TOPOLOGY SYNTHESIS OF GEOMETRICALLY NONLINEAR COMPLIANT MECHANISMS USING MESHLESS METHODS 总被引:1,自引:0,他引:1
This paper presents a new method for topology optimization of geometrical nonlinear compliant mechanisms using the element-free Galerkin method (EFGM). The EFGM is employed as an alternative scheme to numerically solve the state equations by fully taking advantage of its capability in dealing with large displacement problems. In the meshless method, the imposition of essential boundary conditions is also addressed. The popularly studied solid isotropic material with the penalization (SIMP) scheme is used to represent the nonlinear dependence between material properties and regularized discrete densities. The output displacement is regarded as the objective function and the adjoint method is applied to finding the sensitivity of the design functions. As a result, the optimization of compliant mechanisms is mathematically established as a nonlinear programming problem, to which the method of moving asymptotes (MMA) belonging to the sequential convex programming can be applied. The availability of the present method is finally demonstrated with several widely investigated numerical examples. 相似文献
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不平衡量对非线性多转子系统动力特性的影响 总被引:2,自引:0,他引:2
用近代非线性动力学理论分析了弹性支承有间隙和摩擦的非线性刚性多转子系统的复杂运动.建立了支座有间隙和有摩擦的弹性支承的力学模型.导出了这类多转子系统的运动微分方程组.用数值方法得到系统在某些参数区域内的轴心轨迹图,Poincare映射图和分岔图等.以转子不平衡量为控制参数讨论了进出混沌区的不同路径和系统各种形式的拟周期,倍周期和混沌运动.分析结果为定性地改善转子系统的稳定运行状态提供了理论依据. 相似文献