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为了研究三体摩擦界面中第一体变形与第三体状态的相互影响,利用耦合有限元法和离散元法的多尺度法模拟了平行板剪切颗粒第三体的过程。整个模型分为两个区域:有限元区域(上板)和离散元区域(第三体和下板),上板在一定的外载荷压应力下挤压颗粒第三体,下板以恒定的速度剪切颗粒第三体。为实现两个子区域间的相互联系,建立了子区域间应力应变的传递机制。实现了三体摩擦界面的多尺度分析,模拟了平行板剪切颗粒第三体的过程。模拟结果表明:当外载荷压应力低于10MPa时,颗粒间的碰撞增多使得第三体内量纲归一化平均应力增大,宏观摩擦系数也随之增大;在剪切过程中,第三体内部颗粒间的接触随接触角度的分布呈现出一定的规律性,0-90°各区间内的强接触较多,尤其在54°-72°之间;颗粒接触随接触力大小的分布也具有一定的规律性,接触力与第三体颗粒平均接触力的比值在0-0.6之间内的接触较多,随后接触力越大,接触数越少。同时,第一体内压应力分布与第三体内力链的分布相对应,力链越强则与其接触的第一体的压应力越大。
In order to study the interaction between the first body deformation and the third body state in the three-body friction interface, the multi-scale method of coupled finite element method and discrete element method was used to simulate the process of parallel plate shear particle third body. The whole model is divided into two regions: the finite element region (upper plate) and the discrete element region (the third body and the lower plate), the upper plate presses the third body of particles under a certain external load compressive stress, the lower plate is fixed at a constant Speed shear particles third body. In order to realize the mutual connection between two subregions, a mechanism of stress and strain transfer between subregions is established. The multi-scale analysis of the tri-body friction interface was realized, and the process of cutting the third body of the particle by the parallel plate was simulated. The simulation results show that when the external compressive stress is lower than 10MPa, the collision between the particles increases and the normalized average stress in the third body increases and the macroscopic friction coefficient also increases. During the shear process, the third The contact between the particles in the body with the contact angle shows a certain regularity, the strong contact in the range of 0-90 ° is more, especially between 54 ° -72 °; the distribution of particle contact with the contact force is also With a certain regularity, the contact force and the average particle contact force of the third body in the ratio between 0-0.6 more contact, then the greater the contact force, the less the number of contacts. At the same time, the distribution of compressive stress in the first body corresponds to the distribution of the third-party force chain, and the stronger the force chain, the greater the compressive stress of the first body in contact with the third body.