复杂边界下振动颗粒物质的阻尼耗能机理及动态响应研究

Research on the motion characteristics and energy dissipation mechanism of the vibrated granular materials has been a hotspot at present. However the dynamic response mechanism of vibrated granular materials under different vibrating strength is still not clear. In the case of strong vibration excitation, the vortex structure similar to the local homogeneous isotropic turbulence appears in granular materials. And based on the physical similarity, a hydrodynamic model and an energy input model will be built in this project, then the energy dissipation mechanism will be analyzed and energy dissipation ratio will be calculated in different vibrating strength by using theory of turbulence statistics for reference. A mixed-mode boundary condition will be built by analyzing the influence of complex boundary on granular materials, and then the dynamic response of granular material near boundaries will be calculated in different vibration strength by numerical simulation. The mixed-mode boundary condition will be verified and improved by experiments. Then the change rule and mechanism of energy dissipation in Non obstructive particle damping technology（NOPD） will be obtained by combining the energy dissipation mechanism in free vibrational and near-boundary granular materials. The research of this project has important meanings in theory and practical engineering, because it will not only promote the development of granular material theory, but also push the application of granular material theory in NOPD forward.

振动颗粒物质的运动特性及耗能机理是眼下颗粒物质领域的研究热点，然而振动颗粒物质在不同外界激励下的动态响应机理等基本理论问题尚不明确。在较强振动激励下颗粒物质内部会出现与局部均匀各向同性湍流相似的涡结构，基于该物理相似性，本项目将建立颗粒物质的流体力学模型及振动能量输入模型，借鉴湍流统计理论分析并计算自由振动颗粒物质在不同振动强度下的耗能机理及能量耗散率；进而分析复杂边界对颗粒物质运动状态的影响，建立复合型边界条件，采用数值模拟的方法分析和计算不同振动强度下边界附近颗粒物质的动态响应及能量耗散率。通过实验验证并完善上述理论模型，结合自由颗粒物质及边界处颗粒物质在不同振动强度下的能量耗散特性，得到非阻塞性颗粒阻尼技术（NOPD）的耗能机理及耗散特性变化规律。本项目的开展不仅能推进颗粒物质理论自身的发展，还可以推动颗粒物质理论在NOPD减振降噪机理研究中的应用，具有重要的理论及实际价值。