DEM: Shear zones 3. Deformation of a material with inclusions: The effect of material strength

These experiments investigate the effect of the strength of a media on shear deformation between two constraining plates using a discrete element method. The media is 400x35 units, containing 43,565 circular elements with varying radii between 0.25 and 0.5 unit. It has circular boundary conditions so that an element on a boundary in x experiences a force from elements on the opposing boundary and considers them to be neighbouring elements. The media contains a matrix (70% total bonds) and 250 inclusions (30% total bonds) with radii <4.0 units. The number of inclusions, their maximum radii, their breaking strain, and the random number to define inclusion location are constant. 

A zone of weakness is created (y=16.5-18.5) in which 45% of the bonds between elements in the matrix are broken. Experiments run for 400,000 timesteps with a displacement at the boundary plates of 0.00025 unit/ts. 

Outputs in the movies are every unit of displacement. Results are shown relative to their breaking strain (sk.*e.gif, the inclusions are black) and percentage of broken bonds for each element (sk.*bp.gif, coloured as a percentage from 0 (none) to 100 (black)). The *paired movies plot them together.

Results show the effect of increasing strength of the media by increasing the spring strength from 0.1 to 25.0. An explanation of the methodology and images of the results are provided in the accompanying pdf file. 

These results can be compared with experiments that examine the effect of the width of the localisation zone on shearing in: doi:\\10.48420\20368623