We have attempted a multiscale quantification of the internal structure granular materials. The materials, i.e., geometrical information on particles and their spatial arrangement, was described mathematically particle scale using Voronoi–Delaunay tessellations. These tessellations were further modified into two cell systems: solid system void system, with supporting properly reflected. By doing so, systems geometrically physically significant. Taking solid/void cells as microscopic basic...

In this paper, the results of three series drained tests carried out on sands using hollow cylinder apparatus are presented. The noncoaxiality, defined as difference between major principal stress direction and corresponding strain increment direction, is investigated. first tests, sand was isotropically consolidated before being sheared with fixed direction. other two specimens were then by rotating axes while deviator level either (pure rotation) or increased continuously (combined shear...

This paper presents an experimental investigation revisiting the anisotropic stress–strain–strength behaviour of geomaterials in drained monotonic shear using hollow cylinder apparatus. The test programme has been designed to cover effect material anisotropy, preshearing, density and intermediate principal stress on Leighton Buzzard sand. Experiments have also performed glass beads understand particle shape. explains phenomenological observations based recently acquired understanding...

This paper presents numerical experimental results with respect to the responses of two-dimensional granular materials under principal stress rotations. The tests were carried out using discrete element method. A procedure has been developed apply arbitrary or strain paths and measure induced changes. is used investigate elementary behaviour undergoing pure rotation. In this kind test, mean shear are kept constant while direction continuously rotates. Two series experiments have conducted,...

Bedload transport, critical in various natural and engineering systems, involves the complex interaction between particles flowing water. Predicting bedload transport rates has long been a focal point of interest due to its significance understanding river dynamics. Pioneering contributions from Einstein Bagnold have led substantial progress this field derived extensive laboratory in-situ observations, which are yet achieve desired accuracy when validated against real-world hydrological...

This paper employed the theory of directional statistics to study stress state granular materials from particle scale. The work was inspired by stress–force–fabric relationship proposed Rothenburg and Bathurst (1989), which represents a fundamental effort establish analytical macro–micro in mechanics. micro-structural expression tensor σij=1V∑c∈Vvicfjc, where fic is contact force vic vector, transformed into integration grouping terms with respect their normal directions. statistical then...

SUMMARY Multi‐scale investigations aided by the discrete element method (DEM) play a vital role for current state‐of‐the‐art research on elementary behaviour of granular materials. Similar to laboratory tests, there are three important aspects be considered carefully, which proper stress/strain definition and measurement, application target loading paths designed experiment setup, addressed in present paper. Considering volume sensitive characteristics materials, proposed technique,...

This paper presents a numerical investigation on the behavior of three dimensional granular materials during continuous rotation principal stress axes using discrete element method. A dense specimen has been prepared as representative deposition method and subjected to at different deviatoric levels. Significant plastic deformation observed despite that stresses are kept constant. contradicts classical plasticity theory, but is in agreement with previous laboratory observations sand glass...

This paper explores the particle-scale origin of additional shear strength unsaturated granular materials in pendular states induced by capillary effect applying stress–force–fabric (SFF) relationship theory to material stress analysis. The work is based on discrete element simulations with particle interaction model modified incorporate effect. By decomposing total tensor into a contact originating from forces and due effect, directional statistics information are examined. observations...

ABSTRACT Cerebrospinal fluid (CSF) and peripheral blood (PBL) were sampled multiple times from 25 patients with a clinical diagnosis of tuberculous meningitis (TBM) 49 controls, including 27 other infectious diseases the central nervous system 22 noninfectious neurological diseases. We used an enzyme-linked immunospot assay (ELISPOT) to detect anti- Mycobacterium bovis BCG antibody-secreting cells in CSF PBL, PCR repeated insertion sequence (IS 6110 ) specific for tuberculosis CSF,...

In micromechanics, the stress–force–fabric (SFF) relationship is referred to as an analytical expression linking stress state of a granular material with microparameters on contact forces and fabric. This paper employs SFF discrete element modelling investigate micromechanics fabric, force strength anisotropies in two-dimensional materials. The development briefly summarized while more attention placed anisotropy deformation non-coaxiality. Due presence initial anisotropy, demonstrates...

This paper explores the mechanism of deformation noncoaxiality from particle scale. A multiscale investigation has been carried out with particle-scale information obtained discrete element simulation on granular materials. The specimens were prepared anisotropically and sheared in various loading directions. noncoaxiality, i.e., noncoincidence between principal stress direction strain increment direction, was observed. directional statistical theory used to study anisotropies material...