Research On The Mechanical Spectroscopy Of Jamming Behaviors Of Sheared Granular Matter

Granular materials are widely used in our daily life,especially for the industry and daily production.Granular materials are generally macroscopic collections of particles with diameter d>1?m.Granular materials have many specific properties,which are so different from other materials that their basic laws are unclearly.Due to its rich phenomenology under sheare strain,the granular materials have attracted an increasing interest from scientific community in past decades.The force network of granular matter,which is formed by nonlinear Hertz's interaction of granular particles and capillary bridges among adjacent grains,plays a key role on the dynamic of granular matter.Because the force network is too complex to observe the reaction of granular particles and its evolution laws directly in granular matter.To research the mechanism of the dynamic of granular matter,we use a sample force vibration technique to measure the influence of immerse depth,external pressure and shear amplitude on the dissipation spectra of different-size glass beads.We also measure the dissipation spectra of NaCl wet granular matter with different liquid content.We investigated the energy dissipative behavior of glass bead packings with three different millimeter size grains(0.1 mm,0.5 mm and 1.9 mm)by monitoring viscoelastic behaviors.The mechanical spectroscopy evolved with the sheared strain,immersed depth and the applied external pressure.We found that all the systems show the frozen,jamming and fluidized behaviors with increasing the immersed depth of the oscillating probe.Furthermore,the dissipation peak associated to the jamming transition shows up at bigger immersed depth with decreasing the particle size or increasing external pressure.In other words,the critical immersed depth associated with the jamming transition,which shifts to a higher immersed depth when the particle diameter is decreased but move to lower depth as pressure is increased.A qualitative explanation is proposed to explain the complex dynamic behaviors of the glass beads systems based on the change of force chains under shear strain.When the force chains occur non-linear deformation,the granular system is in frozen state.In a stable jamming state,the reconfiguration and rearrangement of granular force chains occur.When all chains are collapse,the granular system is in a fluidization state.To understand the influence of capillary forces on the energy dissipative behaviors of glass beads system.Mechanical spectroscopy(the shear modular G and the related energy dissipation tan?)of NaCl wet granular system is investigated with different liquid content(wt.%)under the constant temperature 25? and air humidity.The NaCl wet granular systems also display jamming behavior when submitted to an external vibration with increasing intensity,which is quiet similar to dry granular matter.With increasing of water content,all the spectra of tan? and modular G show a peak at the water content about 11 wt.%(critical water content).At the same time,the applied shear force has little influence on position of these peaks.All of these behaviors illustrate the structure of system has changed at this moment.