Shear band formation in lunar regolith by discrete element analyses

M. Jiang, Zhenyu Yin, Z. Shen

Research output: Journal article publicationJournal articleAcademic researchpeer-review

12 Citations (Scopus)

Abstract

© 2016, Springer-Verlag Berlin Heidelberg.Few studies in shear band formation have considered the environmental conditions on the Moon, which however are significant for lunar regolith failure in future lunar exploration activities. This paper presents a numerical investigation into the mechanical behavior and strain localization of lunar regolith by means of the discrete element method (DEM). A micromechanical contact model for lunar regolith accounting for van der Waals forces and rolling resistance has been developed, then implemented into a DEM code, PFC2D, and finally applied to analyze the strain localization of lunar regolith through biaxial tests. Biaxial tests without considering van der Waals force effect were also performed as reference to compare with. The distributions inside the sample of grid deformation, void ratio, velocity, averaged pure rotation rate (APR), force chains and local stress during shear banding are analyzed. The simulations show that persistent bands are differently formed under Moon and Earth conditions. Van der Waals forces and rolling resistance play crucial roles in choosing persistent bands from various transient micro-bands before the peak state. Van der Waals forces lead to increased dilation and particle rotation, and enlarged "meso-voids" in force chain distributions within the persistent shear bands. The thickness (inclination to the horizontal) of shear band for the regolith under Moon condition is smaller (larger) than that for regolith under Earth condition.The fields of velocity and APR can reveal the finest heterogeneity in particle displacement (translation and rotation) in the form of transient micro-bands even at the very beginning of shear.
Original languageEnglish
Article number32
JournalGranular Matter
Volume18
Issue number2
DOIs
Publication statusPublished - 1 May 2016
Externally publishedYes

Keywords

  • Discrete element method
  • Lunar regolith
  • Micromechanics
  • Shear band

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)

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