共查询到18条相似文献,搜索用时 703 毫秒
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推力轴承对轴承—转子系统的耦合作用研究 总被引:1,自引:0,他引:1
研究了推力轴承对轴承-转子系统的耦合作用,在传递矩阵法的基础上,提出一种研究考虑推力轴承的影响的轴承-转子系统的动力学的通用方法。 相似文献
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一种基于SMR主动隔振模型的功率流控制方法 总被引:7,自引:0,他引:7
用功率流指标描述主动隔振系统中能量的传输,以传输到接受性的功率流最小为最优化控制目标,推导主动隔振系统中功率流传递的最优控制表达式,提出一种基于SMR主动隔震模型的主动功率流的最优化控制策略,对比分析了被动和主动模型下总功率流的传递特性以及主动控制时传递到基础的各功率流分量的分布特征。针对工程实际中的柔性安装问题,对四边筒支矩形薄板扩动隔振进行了研究。 相似文献
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研究了推力轴承对轴承-转子系统的耦合作用。在传递矩阵法的基础上,提出一种研究考虑推力轴承影响的轴承-转子系统的动力学的通用方法。研究中考虑了如下几个因素:(1)推力盘的静态倾斜;(2)转子的静变形;(3)径向轴承中负荷的重新分配;(4)偏载对径向轴承性能的影响;(5)推力轴承对系统稳定性的影响。研究结果表明,在某些情况下,推力轴承对径向轴承的动特性、转子的静挠度、系统稳定性等具有显著的影响 相似文献
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机器—基础柔性隔振系统的功率流试验研究 总被引:6,自引:0,他引:6
在对楼层安装机器柔性耦合动力系统功率流理论研究的基础上,本文进一步从实验观点研究了机器—基础柔性隔振系统的功率流传递谱。建立了柔性隔振系统实验模型和功率流测试分析系统,从能量观点对机器—隔振器—弹性基础耦合系统的振动传递机理进行了实验研究。通过对称和非对称系统的功率流对比实验,揭示了功率流传递谱的非对称效应,验证了理论分析的正确性。 相似文献
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《中国惯性技术学报》2014,(6)
从三浮陀螺仪的结构出发,考虑浮液和动压气体轴承的特点及隔振作用,运用振动理论和隔振技术,建立并论述了三浮陀螺仪三质量块振动模型。对该模型在受迫振动下的运动方程进行了分析,得到了运动方程的解。对该模型的参数进行了识别,对浮液阻尼特性进行了分析,用摄动法求解了阻尼系数c12;对波纹管弹性系数进行了推导计算,得到了弹性系数k12的表达式;对气体轴承的动态阻尼和刚度进行了分析说明,得到了阻尼系数c23和弹性系数k23的表达式。基于此模型,给出了力传递系数的求解方法以及表达式。对三浮陀螺仪振动传递研究有一定指导作用。 相似文献
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梁系统振动的传递矩阵法 总被引:2,自引:0,他引:2
<正> 1.引言传递矩阵法在机械振动问题中被广泛采用,也是中外学者几乎在所有有关机械振动的教科书和学术专著中加以讨论的问题.但通常的传递矩阵法,要么取分布质量模型,要么取集中质量模型,似乎忽视了两种传递矩阵方法的有机结合,未能充分发挥传递矩阵法在振动分析中的作用.本文试图将集中质量和分布质量模型的传递矩阵结合起来, 相似文献
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Piotr Czop Krzysztof Mendrok Tadeusz Uhl 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(11):1541-1554
Requirements for current trains to be increasingly available have created the need to develop systems that can predict the
quality of both trains and infrastructure components. The paper presents a new approach to the detection of rail truck irregularities,
based on the measurements of bearing box acceleration during the operation of rail vehicles. The proposed procedure is based
on an inverse problem solution, estimating track irregularities from measured acceleration of the applied model of vehicle
dynamics. The simulation study of the proposed method, as well as its implementation, is presented. The method has been successfully
applied for the identification of rail irregularities on a typical Polish railroad and vehicle. 相似文献
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Nonlinear dynamics of an extensible cantilevered pipe conveying pulsating flow is considered in this paper. The fluid flow fluctuates harmonically and exhausts via a nozzle attached to the end of the pipe. Taking into account the extensibility assumption, the coupled nonlinear lateral–longitudinal equations of motion are derived using Hamilton's principle and discretized via Galerkin's method. The adaptive time step Adams algorithm is applied to extract the time response, and then the bifurcation, power spectral density and phase plane maps are plotted for some case studies. Effects of some geometrical parameters such as flow mass, pulsating flow frequency, gravity, nozzle mass and nozzle aspect ratio parameters are studied on the dynamics of such system and the validity of extensibility assumption is investigated and some conclusions are drawn. 相似文献
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Ruben Juanes Christopher W. MacMinn Michael L. Szulczewski 《Transport in Porous Media》2010,82(1):19-30
We study a sharp-interface mathematical model of CO2 migration in deep saline aquifers, which accounts for gravity override, capillary trapping, natural groundwater flow, and
the shape of the plume during the injection period. The model leads to a nonlinear advection–diffusion equation, where the
diffusive term is due to buoyancy forces, not physical diffusion. For the case of interest in geological CO2 storage, in which the mobility ratio is very unfavorable, the mathematical model can be simplified to a hyperbolic equation.
We present a complete analytical solution to the hyperbolic model. The main outcome is a closed-form expression that predicts
the ultimate footprint on the CO2 plume, and the time scale required for complete trapping. The capillary trapping coefficient and the mobility ratio between
CO2 and brine emerge as the key parameters in the assessment of CO2 storage in saline aquifers. Despite the many approximations, the model captures the essence of the flow dynamics and therefore
reflects proper dependencies on the mobility ratio and the capillary trapping coefficient, which are basin-specific. The expressions
derived here have applicability to capacity estimates by capillary trapping at the basin scale. 相似文献
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以超声速HF/DF化学激光和超声速氧碘化学激光(COIL)为代表的气流化学激光(GCL), 因其科学意义、军事和工业应用价值,近30多年来得到了突飞猛进的发展.由于超声速膨胀混合流在控制强放热反应动力学和热力学过程方面的特殊本领,使气体动力学在高功率GCL的发展中起着关键性的作用.高功率GCL性能的分析计算自然也沿用非平衡气体动力学的方法,假定气流(包括激光能级分子和原子)为连续介质,谱线为均匀加宽,并联立求解气体动力学方程组,增益动力学和基于光强迭加原则的辐射传输诸方程,称为速率方程(RE)模型.20世纪70年代后期又提出和发展了GCL性能计算的半气体动理学(SGK)模型,在SGK模型中仍假定气流为连续介质,但同时考虑了激光能级分子微观热运动的贡献,谱线加宽的非均匀加宽效应,并用双参数摄动法求解激光能级分子速度分布函数方程组(即广义Boltzmann方程组), 因此SGK模型是一个同时考虑宏观和微观尺度运动的跨尺度模型.本文综述RE模型和SGK模型以及用它们预测GCL性能的若干研究进展,同时简评等增益模型和腔模(模图样)理论研究的一些进展.最后从气体动力学的角度提出一些值得 进一步研究的课题. 相似文献
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采用川南地区龙马溪组页岩样品,设计了页岩基质解吸-扩散-渗流耦合物理模拟实验,揭示了页岩基质气体流动特征以及压力传播规律.推导了页岩气解吸-扩散-渗流耦合数学模型并且利用有限差分法对数学模型进行数值求解,与实验结果相比较表明该数学模型能够很好地描述气体在页岩基质中的流动规律.同时对页岩基质气体流动的影响因素进行了分析,认为页岩基质的渗透率、扩散系数、解吸附常数等因素均能影响页岩基质气体的流量和压力传播规律,在页岩气藏的开发过程中需要考虑这些参数的影响,该数学模型为页岩气井产能计算提供了更准确的计算方法. 相似文献
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This study presents a dynamic analysis of a flexible rotor supported by two porous squeeze micropolar fluid-film journal bearings with nonlinear suspension. The dynamics of the rotor center and bearing center are studied. The analysis of the rotor–bearing system is investigated under the assumptions of non-Newtonian fluid and a short bearing approximation. The spatial displacements in the horizontal and vertical directions are considered for various nondimensional speed ratios. The dynamic equations are solved using the Runge–Kutta method. The methods of analysis employed in this study are inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincaré maps, and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the dynamic system varies with the nondimensional speed ratios, the nondimensional parameter, and permeability. The modeling results obtained by using the method proposed in this paper can be employed to predict the dynamics of the rotor–bearing system, and the undesirable behavior of the rotor and bearing centers can be avoided. 相似文献
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Thermo‐hydrodynamic‐mechanical multiphase flow model for CO2 sequestration in fracturing porous media 下载免费PDF全文
In this paper, we introduce a fully coupled thermo‐hydrodynamic‐mechanical computational model for multiphase flow in a deformable porous solid, exhibiting crack propagation due to fluid dynamics, with focus on CO2 geosequestration. The geometry is described by a matrix domain, a fracture domain, and a matrix‐fracture domain. The fluid flow in the matrix domain is governed by Darcy's law and that in the crack is governed by the Navier–Stokes equations. At the matrix‐fracture domain, the fluid flow is governed by a leakage term derived from Darcy's law. Upon crack propagation, the conservation of mass and energy of the crack fluid is constrained by the isentropic process. We utilize the representative elementary volume‐averaging theory to formulate the mathematical model of the porous matrix, and the drift flux model to formulate the fluid dynamics in the fracture. The numerical solution is conducted using a mixed finite element discretization scheme. The standard Galerkin finite element method is utilized to discretize the diffusive dominant field equations, and the extended finite element method is utilized to discretize the crack propagation, and the fluid leakage at the boundaries between layers of different physical properties. A numerical example is given to demonstrate the computational capability of the model. It shows that the model, despite the relatively large number of degrees of freedom of different physical nature per node, is computationally efficient, and geometry and effectively mesh independent. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献