共查询到20条相似文献,搜索用时 359 毫秒
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对"圆锥摆粗略验证向心力表达式"实验进行改进,采用减速电动机通过轻杆带动大钢球做匀速圆周运动,形成圆锥摆.改进后的装置运行稳定,操作简单. 相似文献
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Spring pendulum: Parametric excitation vs an external force 总被引:1,自引:0,他引:1
M. Gitterman 《Physica A》2010,389(16):3101-3108
The method of multiple scales is applied to obtain an approximate solution to the nonlinear dynamic equations describing a spring pendulum with the vertical oscillations of the suspension point up to and including the fourth order corrections. The solutions of these equations, where an external force enters the equations multiplicatively, are compared with the solution considered earlier, for the behavior of a spring pendulum subject to an external force, which enters the appropriate equations additively. It turns out that in lower orders in small parameter, the two solutions coincide for the case where the external force and viscous damping force are equally small, but they differ when the damping is much smaller than the external force. 相似文献
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M. Van Zeebroeck E. Tijskens P.Van Liedekerke V. Deli J.De Baerdemaeker H. Ramon 《Journal of sound and vibration》2003,266(3):465-480
A pendulum device has been developed to measure contact force, displacement and displacement rate of an impactor during its impact on the sample. Displacement, classically measured by double integration of an accelerometer, was determined in an alternative way using a more accurate incremental optical encoder. The parameters of the Kuwabara-Kono contact force model for impact of spheres have been estimated using an optimization method, taking the experimentally measured displacement, displacement rate and contact force into account. The accuracy of the method was verified using a rubber ball. Contact force parameters for the Kuwabara-Kono model have been estimated with success for three biological materials, i.e., apples, tomatoes and potatoes. The variability in the parameter estimations for the biological materials was quite high and can be explained by geometric differences (radius of curvature) and by biological variation of mechanical tissue properties. 相似文献
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本文从理论上分析了具有近线性弹性系数悬丝的扭摆在衰减振动时周期的变化规律,得到了与实验相符的结果,提出了如本底扣除法、双悬丝预应力法等几种消除周期变化影响、提高测量精度的方法。
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To elucidate mechanisms of cavitation action on a surface with microcapillary discontinuity and refine the model of the sonocapillary effect, the force acting on a cylinder is correlated with the height of a liquid in the capillary under cavitation, both quantities being measured at the same point of the ultrasonic field. It is found that the force acting on the cylinder is directed toward a cavitation cluster stabilized at the end face of the cylinder. This force can be enhanced with another cylinder placed on the side of the cluster coaxially with the first one. The dynamics of the cavitation cluster depending on the cylinder spacing is investigated in the case when one of the cylinders is on a pendulum suspension. The conditions for self-sustained oscillations of the pendulum are found. The dependence of the attracting force between the cylinders on the ultrasonic frequency and cylinder spacing is derived. The end-face-averaged pressure exerted on a cylinder of diameter 1.2 mm may reach 0.16 kPa, and the intracapillary pressure attains 0.89 kPa. Thus, the sonocapillary effect may be explained, at least partially, by a counterpressure arising from cluster-capillary interaction. This effect can be used in designing cavitation sensors and ultrasonic sources. 相似文献
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Jianhua Liu Qiuliang Wang Luguang Yan 《Physica C: Superconductivity and its Applications》2009,469(13):756-759
The electromagnetic force characteristics along Z direction of a superconducting ball levitated by spherical coils with shaping blocks are calculated based on a semi-analytical method. The calculating results from the semi-analytical method are compared with the finite element analysis (FEA) method through a calculation example. The method can be applied to further analysis of dynamic characteristics and parameter optimization in the suspension system. 相似文献
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由于不同的非惯性系具有不同的加速度,导致单摆在不同的非惯性系中具有不同的振动周期,所以有必要掌握非惯性系下单摆振动周期的计算.基本的计算方法是利用非惯性系动力学方程,结合受力分析求解,但这种方法既要考虑惯性力,又需要进行力的分解,比较麻烦.本文通过引入惯性力势能,给出非惯性系机械能守恒定律,并利用机械能守恒定律对处于特定非惯性系中的单摆周期进行分析计算,得出非惯性系中单摆的振动周期不仅与单摆自身属性有关,而且与非惯性系的运动加速度或角速度有关的结论. 相似文献
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A linearized plane pendulum with the slowly varying mass and length of string and the suspension point moving at a slowly varying speed is presented as an example of a simple 1D mechanical system described by the generalized harmonic oscillator equation, which is a basic model in discussion of the adiabatic dynamics and geometric phase. The expression for the pendulum geometric phase is obtained by three different methods. The pendulum is shown to be canonically equivalent to the damped harmonic oscillator. This supports the mathematical conclusion, not widely accepted in physical community, of no difference between the dissipative and Hamiltonian 1D systems. 相似文献
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变悬点变摆长单摆运动分析 总被引:2,自引:0,他引:2
用两种方法导出了变悬点变摆长单摆的加速度和运动微分方程,分析了小球作周期振动的条件,讨论了角速度最大值的位置,并通过计算机数值计算,画出了小球作周期振动时的相图。 相似文献
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Miroslav Pardy 《International Journal of Theoretical Physics》2007,46(4):848-859
The Lagrange theory of particle motion in the noninertial systems is applied to the Foucault pendulum, isosceles triangle
pendulum and the general triangle pendulum swinging on the rotating Earth. As an analogue, planet orbiting in the rotating
galaxy is considered as the giant galactic gyroscope. The Lorentz equation and the Bargmann-Michel-Telegdi equations are generalized
for the rotation system. The knowledge of these equations is inevitable for the construction of LHC where each orbital proton
“feels” the Coriolis force caused by the rotation of the Earth. 相似文献
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影响单摆振动周期的参数研究 总被引:1,自引:0,他引:1
应用振动分析的方法,研究了单摆的周期受摆角、摆球的线度、地球纬度、摆球离地面的高度、介质黏度和介质密度参数的影响;作出了周期比随参数变化的曲线.结果表明:单摆的周期随摆角、摆球的线度、摆球离地面的高度、介质黏度和介质密度的增大而增大,随地球纬度的增大而减小. 相似文献
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Kazuya Seo Osamu Kobayashi Masahide Murakami Daisuke Yorita Hiroki Nagai Keisuke Asai 《显形杂志》2010,13(2):97-105
Abstract
This paper describes the effect of the seams of a rugby ball on the side force and the flight trajectory of the punted kick. Measurement of the aerodynamic force on a non-spinning rugby ball reveals that the side force coefficient depends on the position of the seam as well as the angle of attack. It was found from pressure-sensitive paint measurements that the seam of the ball is the trigger for initiating low pressure when the seam is situated around 60° from the stagnation point. The flight trajectory of the fluctuating ball can be obtained by numerically integrating the six degree-of-freedom non-linear equations of motion. It was shown that a slower spinning ball fluctuates from side to side during flight because of the asymmetrical pressure distribution on the sides of the ball. 相似文献18.
《Journal of sound and vibration》2004,269(3-5):709-726
This research presents an analytical model to investigate vibration due to ball bearing waviness in a rotating system supported by two or more ball bearings, taking account of the centrifugal force and gyroscopic moment of the ball. The waviness of rolling elements is modelled by the sinusoidal function, and it is incorporated into the position vectors of the race curvature center. The Hertzian contact theory is applied to calculate the elastic deflection and non-linear contact force, while the rotor has translational and angular motions. Both the centrifugal force and gyroscopic moment of the ball and the waviness of the rolling elements are included in the kinematic constraints and force equilibrium equations of a ball to derive the non-linear governing equations of the rotor, which are solved by using the Runge–Kutta–Fehlberg algorithm to determine the new position of the rotor. The proposed model is validated by the comparison of the results of the prior researchers. This research shows that the centrifugal force and gyroscopic moment of the ball plays the important role in determining the bearing frequencies, i.e., the principal frequencies, their harmonics and the sideband frequencies resulting from the waviness of the rolling elements of ball bearing. It also shows that the bearing vibration frequencies are generated by the waviness interaction not only between the rolling elements of one ball bearing, but also between those of two or more ball bearings constrained by the rotor. 相似文献
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New data are presented about energy transfer from an alternating magnetic field to a pendulum with ferromagnetic suspension. For each frequency of the alternating magnetic field there is a certain field intensity for which energy transfer is maximum. 相似文献