Identification of two-dimensional and three- dimensional shear bands in granular media

• Main Authors: Yu-Jie Huang, 黃昱傑
• Other Authors: Kuo-Ching Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/25355725916683709584

碩士 === 國立臺灣大學 === 應用力學研究所 === 99 === Failure of granular materials under external forces is presented by localized strain bands. This localized strain failure is called “ shear bands“. In general, microscopic properties are discontinuous between the shear bands and their neighborhood. Therefore, based on the phenomenon of shear bands, we can determine the location, size, and direction. The Morphologies of shear bands and their evolution are also of interest. Although the macroscopic phenomena had been addressed in many exist literature, microscopic features were largely omitted. In this dissertation, we use the discrete element method (DEM) to simulate the process of granular materials forming shear bands. This simulation is divided into two part. First, We use PFC2D software to simulate a two-dimensional axial test that produces shear bands；Secondly, we use EDEM software to simulate a three- dimensional axial test. There are six microscopic quantities are defined for theoretical modeling. They are the porosity, spin angular velocity, number of contact particles, the bulk part of the gyration tensor , the rotation part of the gyration tensor and the local shear intensity. We investigate the shear bands with these six parameters and discuss the m- icroscopic properties in the 2D and 3D shear bands. Companion, classification and summarization of the granular material proportion using these parameters are performed.