共查询到18条相似文献,搜索用时 93 毫秒
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非轻质弹簧串联系统能量分析 总被引:2,自引:1,他引:1
在弹簧质量不能忽略的情况下,讨论了串联弹簧振子系统动能和弹性势能表达式,结果表明:串联弹簧的动能不仅与两弹簧自身的质量m1、m2有关,还与各弹簧的劲度系数k1、k2密切相关;串联弹簧的弹性势能只由各弹簧劲度系数和串联弹簧的总伸长量决定。 相似文献
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由2个劲度系数相同的轻质弹簧与2个质量相同的弹簧振子在竖直方向耦合组成双自由度振动系统.利用计算机实测技术记录了弹簧振子在竖直方向的运动规律,实验值与理论值吻合很好. 相似文献
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用实验室原有的量筒、 弹簧、 金属球、 塑料球、 玻璃棒等自制竖直弹簧上小球的运动实验装置, 观察、 思
考、 分析其运动过程中力、 加速度、 速度、 动能、 重力势能、 弹性势能等的变化, 找好转折点, 总结其规律 相似文献
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以悬细线拉拽小重物作为等效耦合弹簧,可实现2个一维单摆之间的耦合.通过改变重物的质量或细线的长度,实现等效耦合弹簧的劲度系数的改变. 相似文献
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Negative stiffness is not allowed by thermodynamics and hence materials and systems whose global behaviour exhibits negative stiffness are unstable. However the stability is possible when these materials/systems are elements of a larger system sufficiently stiff to stabilise the negative stiffness elements. In order to investigate the effect of stabilisation we analyse oscillations in a chain of n linear oscillators (masses and springs connected in series) when some of the springs? stiffnesses can assume negative values. The ends of the chain are fixed. We formulated the necessary stability condition: only one spring in the chain can have negative stiffness. Furthermore, the value of negative stiffness cannot exceed a certain critical value that depends upon the (positive) stiffnesses of other springs. At the critical negative stiffness the system develops an eigenmode with vanishing frequency. In systems with viscous damping vanishing of an eigenfrequency does not yet lead to instability. Further increase in the value of negative stiffness leads to the appearance of aperiodic eigenmodes even with light damping. At the critical negative stiffness the low dissipative mode becomes non-dissipative, while for the high dissipative mode the damping coefficient becomes as twice as high as the damping coefficient of the system. A special element with controllable negative stiffness is suggested for designing hybrid materials whose stiffness and hence the dynamic behaviour is controlled by the magnitude of applied compressive force. 相似文献
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Yewan Ma Hansen Chang Zhaowang Wu Yanyan Jiang Juan Li Xunchang Yin Quanjin Liu Lihua Zhang 《声与振动》2019,53(4):139-149
The energy of a spring with a well-distributed mass ms is theoretically studied in this paper. The solution of the wave equation is derived in detail, and then the kinetic energy and potential energy of the spring are studied with the wave
equation, as well as the kinetic energy of the oscillating mass M. The kinetic energy and potential energy of the spring, and total energy are numerically simulated for different ratios ms/M with considering the spring’s mass, which
makes the property of energy of the oscillating system understood easily. 相似文献
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On the design of a high-static-low-dynamic stiffness isolator using linear mechanical springs and magnets 总被引:3,自引:0,他引:3
The frequency range over which a linear passive vibration isolator is effective is often limited by the mount stiffness required to support a static load. This can be improved upon by incorporating a negative stiffness element in the mount such that the dynamic stiffness is much less than the static stiffness. In this case, it can be referred to as a high-static-low-dynamic stiffness (HSLDS) mount. This paper is concerned with a theoretical and experimental study of one such mount. It comprises two vertical mechanical springs between which an isolated mass is mounted. At the outer edge of each spring, there is a permanent magnet. In the experimental work reported here, the isolated mass is also a magnet arranged so that it is attracted by the other magnets. Thus, the combination of magnets acts as a negative stiffness counteracting the positive stiffness provided by the mechanical springs. Although the HSLDS suspension system will inevitably be nonlinear, it is shown that for small oscillations the mount considered here is linear. The measured transmissibility is compared with a comparable linear mass-spring-damper system to show the advantages offered by the HSLDS mount. 相似文献
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Gerolf Ziegenhain 《哲学杂志》2013,93(26):2225-2238
We investigate the dependence of the hardness of materials on their elastic stiffness. This is possible by constructing a series of model potentials of Morse type; starting with modelling natural Cu, the model potentials exhibit an increased elastic modulus, while keeping all other potential parameters (lattice constant, bond energy) unchanged. Using molecular-dynamics simulation, we perform nanoindentation experiments on these model crystals. We find that the crystal hardness scales with the elastic stiffness. Also the load drop, which is experienced when plasticity sets in, increases in proportion to the elastic stiffness, while the yield point, i.e. the indentation at which plasticity sets in, is independent of the elastic stiffness. 相似文献
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基于纳米摩擦能耗理论,利用分子动力学方法建立了公度接触下支撑刚度梯度变化的石墨烯层间摩擦力模型,分析了基底质心刚度和支撑刚度梯度变化对基底和薄片各接触区摩擦能耗的贡献.结果表明:软边界区始终贡献驱动力;硬边界区贡献的摩擦力最大,且随着支撑刚度的增大,硬边界区对总摩擦的贡献比也越高.各接触区的摩擦力是薄片和基底之间的褶皱势和接触区产生的法向变形差两部分的共同作用.前者是公度接触下阻碍滑移的界面势垒和刚度梯度方向上不同刚度支撑原子热振动引起的势梯度;后者是接触边界过渡区两侧原子的非对称变形和自由度约束突变引起的非平衡边界势垒相耦合的结果.本文对研究公度接触下刚度梯度支撑的纳米器件的相对运动规律有指导意义. 相似文献
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固体间界面的物理模型和界面对声波的反射 总被引:4,自引:0,他引:4
简要描述了模拟两固体间界面特性的弹簧模型,该模型最早是根据静力学方法提出的,后来用固体间界面薄层的声波反射方法加以改进,从界面弹簧模型可以方便地得到界面外近似边界条件,其中包含界面“弹簧”振子的劲度常数和质量,文章还给出了两相间固体中界面声反射系数的表达式,介绍了测量界面劲度常数的超声反射谱方法。最后讨论了仍关声波与界面相互作用研究领域中最近的一些研究进展。 相似文献
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We explore the performance of a nonlinear tuned mass damper (NTMD), which is modeled as a two degree of freedom system with a cubic nonlinearity. This nonlinearity is physically derived from a geometric configuration of two pairs of springs. The springs in one pair rotate as they extend, which results in a hardening spring stiffness. The other pair provides a linear stiffness term. We perform an extensive numerical study of periodic responses of the NTMD using the numerical continuation software AUTO. In our search for optimal design parameters we mainly employ two techniques, the optimization of periodic solutions and parameter sweeps. During our investigation we discovered a family of detached resonance curves for vanishing linear spring stiffness, a feature that was missed in an earlier study. These detached resonance response curves seem to be a weakness of the NTMD when used as a passive device, because they essentially restore a main resonance peak. However, since this family is detached from the low-amplitude responses there is an opportunity for designing a semi-active device. 相似文献