DEM investigation of macro- and micro-mechanical properties of rigid-grain and soft-chip mixtures--颗粒学报PARTICUOLOGY

Zhang, J., Chen, X., Zhang, J., Jitsangiam, P., & Wang, X. (2021). DEM investigation of macro- and micro-mechanical properties of rigid-grain and soft-chip mixtures. Particuology, 55, 128-139. https://doi.org/10.1016/j.partic.2020.06.002

DEM investigation of macro- and micro-mechanical properties of rigid-grain and soft-chip mixtures

Junqi Zhang ^a, Xiaobin Chen ^a, Jiasheng Zhang ^a, Peerapong Jitsangiam ^b, Xiang Wang ^a *

a Central South University, School of Civil Engineering, Changsha, Hunan, China
b Chiang Mai University, Department of Civil Engineering, Chiang Mai, Thailand

10.1016/j.partic.2020.06.002

Volume 55, April 2021, Pages 128-139

Received 10 March 2020, Revised 8 June 2020, Accepted 11 June 2020, Available online 7 July 2020, Version of Record 3 February 2021.

E-mail: wang.xiang@csu.edu.cn

Highlights

• A soft-chip calibration method is proposed from conventional tensile test results.

• Numerical triaxial tests of rigid grain–soft chip mixture were conducted using DEM.

• The effects of chip content on rigid grain–soft chip mixtures are investigated.

Abstract

We investigated the macro- and micro-mechanical properties of rigid-grain and soft-chip mixtures (GCMs) through numerical simulations using the discrete element method. We present a novel framework for the discrete modeling of soft chips and rigid grains in conjunction with calibration processes. Several numerical triaxial tests were also performed on GCMs with 0%, 10%, 20%, and 30% volumetric chip contents, P. The simulation results demonstrate that increasing P leads to higher GCM toughness, higher deviatoric peak stress, and higher corresponding shear strain. Higher P also contributes to more volume contraction and less dilation. The friction angles at both the peak and residual state significantly increase with increasing P. In view of the micro-mechanical features, strong contact force chains develop along the loading direction, which results in considerable anisotropy in the peak and residual states. Both the formation of strong force chains and rotation of grains decrease with increasing P, whereas the grain sliding percentage increases. The tensile force is mobilized with shearing and higher P leads to less mobilization of the tensile force. These findings are useful for better understanding the internal structure of GCMs with different soft-chip contents, especially in granular mixture mechanics and geomechanics.

Graphical abstract

Keywords

Rubber chips; Rigid–soft mixtures; Micro-mechanical properties; Triaxial test; Discrete element method

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