共查询到18条相似文献,搜索用时 125 毫秒
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利用T r a c k e r视频软件的自动追踪功能, 有效地跟踪油浸弹簧振子的阻尼振动, 实时描绘出振动的位
移 时间图像, 利用软件自带的功能拟合出振动曲线方程, 计算出该弹簧振子的阻尼系数, 并通过转换坐标得到运动
的相图 相似文献
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利用拉格朗日方程建立了单质点弹簧振子非线性振动方程,作出了回复力、势能随坐标的变化曲线以及相图.应用第一类完全椭圆积分求出了非线性振动周期的精确解.应用线化和校正法对单质点弹簧振子的周期和近似解进行了求解.利用Maple计算机绘图,分别作出了它们的周期近似解与周期精确解随振幅的变化曲线以及近似解与数值解的变化曲线.利用线化和校正法所求得的近似解与数值解比较,具有简单实用、精度高、相对误差低等优点,在求解非线性振动中具有一定的实用价值. 相似文献
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本文讨论了有质量弹簧的弹簧振子的动力学,运用哈密顿函数解出了振子的运动方程,并推导出振动周期与弹簧质量和阻尼的关系. 相似文献
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针对人教版选修教材中简谐运动实验中的不足,对该实验装置进行了改进.改进后的实验装置在弹簧振子两端加2个滑环,并用铁丝穿过滑环,以防止弹簧振子在振动过程中旋转,且可以减小摩擦;同时又用磁性笔代替绘图笔,由慢速电机(旋转可调)牵引磁性黑板,以实现描述弹簧振子的运动轨迹的目的. 相似文献
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对在粗糙水平面上作振动的弹簧振子进行研究,探讨该弹簧振子最后停止的位置,估算了弹簧振子的振动总次数,得出弹簧振子的相轨迹. 相似文献
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With vibration isolation of buildings and turbomachinery blades in mind, we study the dynamic behaviour of a single-mass two-degree-of-freedom oscillator with dry friction damper, viscous damper and elastic spring connected in parallel. The mass is mounted on an elastic supporting plate allowing movement in two directions on a plane. We formulate a multi-dimensional friction model, from which the sliding conditions and the sticking conditions of the mass are derived. For calculations we develop a group-preserving scheme, which preserves the projective proper orthochronous Lorentz group PSOo(2,1) symmetry of the model in the sliding phase so as to satisfy automatically the sliding conditions at each time step without iteration at all. The oscillator is then subjected to simple harmonic excitations, and the responses are displayed. According to the simple harmonic balance method together with a circular orbit assumption on displacements, we derive closed-form formulae for handily estimating the steady state responses, which are then compared with the results calculated by the group-preserving scheme to confirm the applicability of the formulae. We also derive formulae specifically for a two-dimensional friction oscillator with rigid base support, which include an exact formula of the magnification factor and a simple formula for estimating the minimum driving force amplitude (or the maximum friction force bound) to avoid sticking. 相似文献
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Although a brake pad and disc have many modes of vibration, when it is unstable and hence noisy then frequently only a single mode of the complete system contributes to the vibration. In this condition, only a few modes are required to model the system. In this paper, a two-degree-of-freedom model is adopted where the disc and the pad are modelled as single modes connected by a sliding friction interface. Using this model, the interaction between the pad and the disc is investigated. Stability analysis is performed to show under what parametric conditions the system becomes unstable, assuming that the existence of a limit cycle represents the noisy state of the disc brake system. The results of this analysis show that the damping of the disc is as important as that of the pad. Non-linear analysis is also performed to demonstrate various limit cycles in the phase space. The results show that the addition of damping to either the disc or the pad alone may make the system more unstable, and hence noisy. 相似文献
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颗粒物质由离散的固体颗粒组成, 受到周期性振动时可以表现出复杂的动力学行为. 这些行为往往受众多因素的影响, 如空气阻力和器壁摩擦力等. 针对受振颗粒体系中冲击力的倍周期分岔现象, 通过抽真空或将容器底镂空消除空气阻力, 单独研究器壁滑动摩擦力的影响. 结果表明在仅有器壁摩擦力作用的情况下, 倍周期分岔过程仅受约化振动加速度的控制, 与颗粒的尺寸、颗粒层数及振动频率无关. 将器壁摩擦力处理成一个大小恒定、方向与颗粒和器壁相对速度反向的阻力, 并包含到完全非弹性蹦球模型中, 能够对所观察到的现象给出很好的解释. 通过对倍周期分岔点测量平均值的拟合, 得到器壁滑动摩擦力的大小约为颗粒总重量的10%.
关键词:
颗粒物质
器壁摩擦力
倍周期分岔
冲击力 相似文献
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改进DIS实验系统中的“弹簧振子的振动图像”实验 总被引:1,自引:1,他引:0
对DIS实验系统中的"弹簧振子的振动图像"实验中存在的不足进行了改进,实验引入气垫导轨,减少了外界对弹簧振子的影响,得到了较为理想的弹簧振子的振动图像,并提高了原实验的精度和趣味性. 相似文献
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Jaeyoung Kang 《Journal of sound and vibration》2011,330(22):5490-5499
The theoretical model for the ball joint squeak problem is proposed. The ball joint is modeled as a sphere attached to a rotating flexible beam and it is in contact with a semi-spherical rigid socket. The relative rotation and vibration between the ball and socket produces friction stresses causing the dynamic instability of the system. The squeak propensity of the ball joint system is numerically investigated through the eigenvalue sensitivity analysis at the sliding equilibrium. Stability analysis shows that the bending modes of the beam can produce the dynamic instability under the negative friction-velocity slope. It is also highlighted that the squeak propensity under the poor friction characteristics can be controlled by the system parameters such as the sliding speed, the contact stiffness, the radius of the ball, the axial load and the tilting angle. 相似文献
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C.-S. LIUW.-T. CHANG 《Journal of sound and vibration》2002,258(2):247-268
A single-degree-of-freedom system with the parallel presence of a linear spring, a viscous damper and a contact dry friction device is studied here. The mass may slide or stick on the belt when the driver moves periodically or at a constant speed. We derive closed-form solutions according to a more complete two-phase formulation, and some interesting behaviours of the considered system are displayed. For the non-damping oscillator belt with fixed, we offer closed-form formulae for estimating the maximum displacement and the minimum driving speed amplitude needed to prevent sticking. Two friction laws are considered. For the Coulomb friction system, the positive damping term suffices to avoid the climb motion of the mass slider. We also investigate the friction behaviour of the mass slider under the influence of the friction force bound on mass speed, whose curve has negative slope when the mass speed is less than a certain value vmin. For the speed-dependent friction system we identify a critical speed denoted by v*. According to the qualitative analysis in the phase plane we give simple criteria of the parameter values for stable equilibrium point as well as for stable limit cycle. When v varies from vv* to v<v*, subcritical Hopf bifurcation occurs. For the latter case the mass slider undergoes a slide-stick motion, but by increasing the driving speed the slide-stick motion can be avoided. 相似文献