Study On Period-doubling Behavior Of The Wet Granular Matter

Experiments are performed to investigate the motion of wet granular matter subjected to mechanical vertically vibration. The study consisit of two parts.(1) The study of the period rate of the wet particle block under the vertical vibrating.(2)The study of the internal energy dissipation of the particle block under the vertical vibrating.The results of the period rate of the wet particle block under the vertical vibrating indicated that, motion of the wet particle block presents the period-doubling property and its period is integral multiples of the exciting period. The period rate not only depends on the normalized acceleration but also relates to the exciting frequency. The period rate increases in a stepwise way with the normalized acceleration. The low exciting frequency corresponds to the small period rate, the high frequency corresponds to the big period rate. Based on the bouncing ball model, a dynamical analysis of the period doubling behavior has been given. The results showed that the period rate vs the normalized acceleration is better agreement with the experimental results, but the period rate vs the exciting frequency is different from the experimental results. Combined with the features of granular matter, an explanation for the deviation between the theory and the experiment is presented.The results of the internal energy dissipation of the particle block under the vertical vibrating indicated that, particle size and viscidity of internal paticles have effects on the particle block. When the external frequecy and the vibrating strength are the same, nomatter the dry particle block or the wet particle block, the big particles dissioated less energy than the small particles; Nomatter big particle block or the small particle block, the wet particle block dissipated less energy than the dry particle block, namely, the internal energy dissipation between particles is mainly the collision dissipation. Dynamic analysis of the experimental results has been done and established the quantitative relationship of the average flight time and the vibrating strength and the internal friction factor(internal structure depend on the particle size, the viscidity of particle, etc.). Using the Origin software for fitting the experimental data, the fitting results are well agreed with the experimental results. The influence of the internal energy dissipation of particle block, which is connected with stucture of inside particles and the outside external frequecy, were alalyzed.