Metastable states of a low‐frequency mesodynamic pendulum
Metastable states of a low‐frequency mesodynamic pendulum
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低频介动力摆的亚稳态
DOI：
10.1063/1.104031
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发表时间：
1990
影响因子：
4
通讯作者：
R. Peters
中科院分区：
文献类型：
--
作者：
R. Peters
对一个物理摆的自由衰变作了初步的研究，这个摆的质量由两个金属摆控制，它的周期可以调整到30秒以上。腐蚀机制主要是蠕变内摩擦引起的非弹性。这种蠕变的松弛谱表明了一种机械巴克豪森效应。与大能量下的指数衰减相反，低能量和长周期运动具有可重复的亚稳态特征。相位在大多数状态之间的转换中被保留，即使转换可能是混沌的。存在一个不同于Pb和Cu的最低谐波态，在这个最低谐波态下，系统从自由衰变过渡到随机涨落耗散。这种随机状态的噪声比电子噪声大，功率谱密度图显示它包含以钟摆频率的1/4的整数倍混合的次谐波。
A preliminary study has been made of the free decay of a physical pendulum whose mass is dominated by two metal bobs, and whose period can be adjusted to exceed 30 s. The decay mechanism is predominantly anelasticity from internal friction of creep. The relaxation spectrum of this creep suggests a mechanical Barkhausen effect. In surprising contrast to exponential decay at large energy, the motion at low energy and long period is characterized by repeatable metastable states. Phase is preserved in the transition between most states even though the transitions may be chaotic. There is a lowest harmonic state which is different for Pb and Cu bobs, and below which the system transitions from free decay to stochastic fluctuation‐dissipation. Noise of this stochastic state is larger than electronic noise, and power spectral density plots show that it contains mixtures of subharmonics at integral multiples of 1/4 the pendulum frequency.