关键词: 数字图像相关, 颗粒体系, 力链破坏, 传力角

Abstract: A particle system has a complex force chain network, and its balance and stability depend on the geometrical structure and mechanical properties of the internal force-chain framework. To depict the micro-mesoscopic mechanical behavior of the particle system, we start with specifying the local arrangement morphology of particles, the contact force between particles and the physical parameters of particles and external load, and then conduct the deformation tests on the particle system subjected to a concentrated force based on the two dimensional-digital image correlation (2D-DIC). With combining with the DIC test method, the Newtonian mechanics theory and the particle linear momentum balance are used to obtain the contact force and the direction of contact force between the particles, and then determine the kinetics of the force chain. Once the distribution and variation of contact force between the particles are obtained, the force chain is demonstrated. It is suggested that there are two states in particle system, namely, the transverse force transmission state and the longitudinal force transmission state. The parameters such as the angle ? between the normal of the contact surface of particles and the horizontal axis, the force transmission angle ? are analyzed. The influences of ? and ? on the force chain damage are discussed. The parameters, the ratio R of the particle diameter d to the external load diameter D and the maximum number N of particles contacted with the loading rod, are analyzed. All of the above can provide a guideline for describing the evolution, destruction and reconstruction mechanism of the force chain.

Key words: digital image correlation, particle system, force chain damage, angle of force transmission