Experiment Test And DEM Analysis Of Buffering Capacity Of Granular Matter

Granular matter is a complex energy dissipation system. Under impact loads, the energy of impact object can be dissipated effectively by the inter-particle friction and extrusion of particles. The force chain structures in granular system can extend the local impact in spatial dimension and expand the instantaneous impact in temporal dimension to obtain the effective buffering effect. Based on fine buffer and dissipation characteristics of granular material, its buffering performances under the impact load is tested systematically and simulated by discrete element method. The affecting factors of particle buffer are analyzed in detail. The research above can reveal the basic mechanical behaviors of granular materials under impact loads, and can also be aided to the engineering applications in impact absorption of granular materials.With the buffering performance of granular experiment tests, the relationship between impact force and filling thickness of grain is studied. The critical thickness of granular materials is revealed and its mechanism is explained. The influence of shape factor of granular particles on the buffering effect is also tested. For the small particle size, the diameter plays an important rule, as while, the form affects obviously in the large particle size. Meanwhile, the buffer performance is also compared with different impact projectile. Finally, the impaction process is simulated with discrete element method to understand the dynamic dissipation process of the projectile. The distribution of impact force under different impact velocities and granular depths is researched. Force chain structures are discussed to analyze the buffer effect of the granular system and the further works are also discussed.