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研究了垂直振动激发下钨颗粒的动态有效质量?M(ω)和耗散功率p(ω)随频率ω的依赖关系.实验发现,在给定的振动幅度下,自由表面样品有效质量的实数部分M1(ω)、虚数部分M2(ω)以及耗散功率p(ω)随频率的变化曲线均出现一个尖锐的共振峰.随着在颗粒上表面施加压强的增大,M1(ω),M2(ω)和耗散功率p(ω)曲线的峰值频率向高频移动,且峰值高度也相应增大.进一步研究发现,有效质量实数部分的共振频率fg随表面压强P的变化满足分段幂律规律,当P较小时,幂指数为0.3,当P较大时,幂指数减小为1/6.颗粒系统的品质因子的倒数1/Q随压强P的变化满足指数衰减规律.
The dependence of the dynamic effective mass M (ω) and the dissipative power p (ω) on the frequency ω of tungsten particles under vertical vibration excitation was investigated. It was found that the real number of effective masses of the free surface sample for a given vibration amplitude A sharp resonance peak appears in the curves of M1 (ω), M2 (ω) and dissipation power p (ω) as a function of frequency.With the increase of the applied pressure on the surface of the particles, M1 (ω), The peak frequencies of the M2 (ω) and the dissipative power p (ω) curves move to higher frequencies and their peak heights also increase.Further studies show that the resonant frequency fg of the real part of effective mass varies with the surface pressure P, When the P is small, the power exponent is 0.3, and when P is larger, the power exponent is reduced to 1/6. The reciprocal 1 / Q of the quality factor of the granular system satisfies the exponential decay law.