共查询到18条相似文献,搜索用时 521 毫秒
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运用跃变旋转矢量法,即通过旋转矢量的起点、长度和相位的变化规律对受到空气弱阻尼作用和滑动摩擦力作用的弹簧振子的振动进行了研究.讨论了在滑动摩擦力作用下空气阻尼为临界阻尼和欠阻尼情况下的弹簧振子的运动,根据阻尼和初值情况得出不同的振动曲线.并对弹簧振子4种相图和相图旋转矢量进行了比较. 相似文献
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应用法拉第电磁感应定律推导出非磁性旋转导体盘的转动衰减方程;定义并测量了导体盘的摩擦阻尼系数和电磁阻尼系数;分析研究了电磁阻尼系数与励磁电流平方间的关系. 相似文献
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A simple experimental method is presented in this paper to evaluate the frequency dependent rubber mount stiffness and damping characteristics by utilizing the measured complex frequency response function from impact test and by least-squares polynomial curve fitting the data obtained from the test. The study shows the transition of the rubber mount stiffness from static to dynamic values. Using the experimentally estimated values of the rubber mount stiffness and damping, the dynamic response of the tested spring-mass system using a rubber mount as the elastic element can be accurately reproduced. In contrast, it is found that the single degree of freedom ideal spring-mass model using constant stiffness and damping values can only predict the response of the system accurately at resonance but not at non-resonance frequencies. The proposed method is validated by comparing its results with those obtained by using mechanical shaker excitations and those of conventional direct stiffness method using blocked transfer frequency response functions. 相似文献
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一维振子的过阻尼与临界阻尼现象x-t曲线的计算机描绘 总被引:2,自引:0,他引:2
用VISUAL C++程序实现了一维振子的过阻尼与临界阻尼现象x-t曲线的计算机描绘,程序具有良好的界面和坚固性,通过运行程序,可以让学生从交互操作过程中深入理解一维振子的过阻尼和临界阻尼现象。 相似文献
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从理论和实例上对线性振子过阻尼和临界阻尼特性曲线进行分析对比,发现在某特定条件下过阻尼能较快地恢复到平衡位置,还发现从平衡位置开始的线性振子,过阻尼状态时峰值较小,恢复时间较长;而临界阻尼状态下恢复时间较短,峰值较大. 相似文献
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由于空气阻尼的作用,测量大摆角单摆“周期”时,测量累计次数增加造成平均“周期”不断减小,在无阻尼实验设定下,系统误差随之增大而随机误差却因此减小.基于弱阻尼大摆角单摆的运动方程与“周期”计算公式,通过数值计算不同摆长与摆角下使不确定度最小的最佳累计摆动次数,发现如果进行单次测量,采用秒表测量时最佳累计摆动次数往往需要大于20次,采用光电门测量时,在不同的摆长和摆角下,测量次数往往也不止1次;而如果采用多次测量,则可以显著减小每次测量所需要的最佳累计摆动次数.采用计算所得最佳摆动次数测量可以将周期测量的不确定度减小到A类不确定度的√2倍. 相似文献
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This paper aims at developing an integrated design method of the active/passive hybrid type of piezoelectric damping system for reducing the dynamic response of the flexible structures due to external dynamic loads. The design method is based on the numerical optimization technique whose objective function is a control effort of the active damping. A vibration suppression performance, which is evaluated by the maximum value of the gain of the frequency response function of the structure, is constrained. In order to demonstrate the structural damping capability of the hybrid type of piezoelectric damping system designed by proposed method, numerical simulation and laboratory experiment will be done using a three-story flexible structure model equipped with 12 surface bonded PZT tiles pairs. Both numerical and experimental results indicate that the optimally designed hybrid piezoelectric damping system can be successfully achieving excellent performance as compared to a conventional purely active piezoelectric damping system. 相似文献