Triaxial Test Simulations with Discrete Element Method and Hydrostatic Boundaries
Publication: Journal of Engineering Mechanics
Volume 130, Issue 10
Abstract
A new boundary condition has been developed for the discrete element method. This boundary is different from the conventional periodic, rigid, or flexible boundries. This new boundary mechanism was developed to simulate triaxial tests. The new boundary, hydrostatic boundary, simulated the chamber fluid but not the rubber membrane. When a particle (ellipsoids in our simulations) contacts the hydrostatic boundary, pressure is developed. The interaction between the particle and the boundary is calculated analytically based on geometry. This hydrostatic boundary condition was implemented into an existing ellipsoidal discrete element code. Triaxial compression drained tests were performed with both periodic and hydrostatic boundaries. The result showed an increase in friction angle over the values observed from the periodic boundary mechanism. The result also closely resembles the experimental triaxial data. Thirteen specimens were generated and were used to investigate the following variables: particle shape, specimen size, and void ratio. A unique slope of the linear relationship between friction angle and void ratio was identified for monosize specimens of different particle shapes. It is found that the friction angle decreases as the aspect ratio increases provided that the void ratio of the two specimens is the same. The friction angle is linear proportional to the coordination number for monosize specimens regardless the specimen size. Also, the specimen size does not influence the behavior of two-size specimens.
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References
1.
Bardet, J. P., and Proubet, J. (1991). “A numerical investigation of the structures of persistent shear bands in granular media.” Geotechnique, 41, 599–613.
2.
Bashir, Y.M., and Goddard, J.D. ( 1991). “Simulation of the quasi-static deformation of 2D assemblage of rigid discs.” Mechanics computing in 1990’s and beyond, Vol. 2, 1264–1268.
3.
Cundall, P. A. (1989). “Numerical experiments on localization of frictional materials.” Ingenieur-Archiv, 59, 148–159.
4.
Cundall, P. A., and Strack, O. L. (1979). “A discrete numerical model for granular assemblies.” Geotechnique, 29(1), 47–65.
5.
Dobry, R., and Ng, T.-T. (1992). “Discrete modeling of stress–strain behavior of media at small and large strain.” Eng. Comput., 9, 129–143.
6.
Kuhn, M. ( 1992). “A flexible boundary for three-dimensional DEM particle assemblies.” Proc., 2nd Int. Conf. on Discrete Element Methods, Boston, 227–234.
7.
Lin, X., and Ng, T.-T. (1997). “A three dimensional discrete element model using arrays of ellipsoids.” Geotechnique, 47(2), 319–329.
8.
Matsushima, T., and Konagai, K. ( 2001). “Grain-shape effect on peak strength of granular materials.” Computer methods and advances geomechanics, Vol. 1, Desai et al. eds., Balkema, Rotterdam, The Netherlands, 361–366.
9.
Ng, T.-T. (1999). “Fabric study of granular materials after compaction.” J. Eng. Mech., 125(12), 1390–1394.
10.
Ng, T.-T. ( 2002). “Hydrostatic boundaries in discrete element methods.” Proc., 3rd Int. Conf. on Discrete Element Methods, Santa Fe, N.M., ASCE, New York, 47–51.
11.
Ng, T.-T., and Wang, C. ( 1999). “Numerical study of arrays of ellipsoids.” Proc., 13th EMD Conf., (CD-ROM) ASCE, Baltimore.
12.
Ng, T.-T., and Wang, C. (2001). “Comparison of a 3-D DEM simulation with MRI data.” Int. J. Numer. Analyt. Meth. Geomech., 25(5), 495–507.
13.
Rothenburg, L., and Bathurst, R. J. (1992). “Micromechanical features of granular assemblies with planar elliptical particles.” Geotechnique, 42(1), 79–95.
Information & Authors
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Published In
Journal of Engineering Mechanics
Volume 130 • Issue 10 • October 2004
Pages: 1188 - 1194
Copyright
Copyright © 2004 ASCE.
History
Published online: Oct 1, 2004
Published in print: Oct 2004
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