This paper presents the rheology of weakly wetted granular materials in the slow frictional regime, using Discrete Element Method (DEM) simulations. In a split-bottom ring shear cell geometry a slow, quasi-static deformation leads to wide shear bands away from the walls. Dry non-cohesive and cohesive materials are compared in order to understand the effect of liquid bridge capillary forces on t...

Numerical simulations of crack initiation which use a cohesive zone law to model a weak interface in the solid are often limited by the occurrence of an elastic snap-back instability. At the point of instability, quasi-static finite element computations are unable to converge to an equilibrium solution, which usually terminates the calculation and makes it impossible to follow the postinstabili...

A micro-mechanics damage model is proposed based on homogenization of penny-shaped cohesive micro-cracks (Barenblatt–Dugdale type) in a three dimensional representative volume element. By assuming that macro-hydrostatic stress state has dominant effect on permanent crack opening, a class of pressure sensitive yielding potentials and corresponding damage evolution laws have been derived. The mer...

A new experimental technique is developed to determine the onset and evolution of delamination in fiber-reinforced composites under impact loading. The configuration uses a split-Hopkinson bar for low-velocity impact loading and two Polytec laser vibrometer systems for real-time monitoring of the initiation and progression of delamination. The experiment allows the histories of load, displaceme...

A new flow enhancement system is developed for cohesive powders. It is based on the concept of multiple, point source, internal excitations. In this system, a mass of small permanent-magnetic particles are placed in the discharge zone of a hopper, and then an oscillating magnetic field is applied to excite these magnets. A screen is placed at the exit to keep the magnets within the hopper. The ...

Investigating the mechanical behaviour of silica bodies in oil palm empty fruit bunches (OPEFB) is important to improve the process of silica body removal. This study will assist in providing an understanding of the role of OPEFB as a bioresource material for the bioconversion process. The microstructure of silica bodies/protrusions on the OPEFB fibre surface was modelled using the finite eleme...

Here, we investigate the ultrastructural origins of the strength of bone, which is critical for proper physiological function. A combination of dual nanoindentation, three-dimensional elastic-plastic finite element analysis using a Mohr-Coulomb cohesive-frictional strength criterion, and angle of repose measurements was employed. Our results suggest that nanogranular friction between mineral pa...

We propose a new two-dimensional meshing algorithm called PINW able to generate meshes that accurately approximate the distance between any two domain points by paths composed only of cell edges. This technique is based on an extension of pinwheel tilings proposed by Radin and Conway. We prove that the algorithm produces triangles of bounded aspect ratio. This kind of mesh would be useful in co...

The recognition of biological differences as an important explanatory and predictive element in political behavior has created the need to integrate various models from a variety of fields into a more cohesive theoretical framework. The ostensibly perplexing coexistence of individual differences in the face of universal human design needs to be reconciled. Here we introduce evolution as a theor...

soft-sphere discrete element method (dem) and navier-stokes equations were coupled with equations of energy for gas and solids to investigate the process of agglomeration in fluidized bed of polyethylene particles at high temperature. the newton’s second law of motion was adapted for translational and rotational motion of particles and agglomerates. the cohesive force for polyethylene particles...