The role of constitutive models in MPM simulations of granular column collapses

Abstract

The granular column collapse is a well-established experiment which consists of having a vertical column of granular material on a flat surface and letting it collapse by gravity. Despite its simplicity in execution, the numerical modelling of a column collapse remains challenging. So far, much attention has been dedicated in assessing the ability of various numerical methods in modelling the large deformation and little to the role of the constitutive model on both the triggering mechanism and the flow behaviour. Furthermore, the influence of the initial density, and its associated dilatancy and strength characteristics, have never been included in the analyses. Most past numerical investigations had relied on simple constitutive relations which do not consider the softening behaviours. The aim of this study is to illustrate the influence of the constitutive model on the on-set of failure, the flow behaviour and the deposition profile using the material point method. Three constitutive models were used to simulate the collapse of two granular columns with different geometries and for two densities. The results of the simulations showed that the constitutive model had a twofold influence on the collapse behaviour. It defined the volume of the mobilised mass which spread along the flat surface and controlled the dissipation of its energy. The initial density was found to enhance the failure angle and flow behaviours and was more significant for small columns than for larger ones. The analysis of the potential energy of the mobilised mass explained the existence of two collapse regimes.

An edge‐based strain smoothing particle finite element method for large deformation problems in geotechnical engineering

“…To further demonstrate the proposed method's ability to solve large deformation geotechnical problems, the rectangular channel soil collapse tests conducted by Bui et al are analysed and the results compared with the experimental data and other numerical solutions (ie, MPM and SPH ). In the experiments, small aluminium bars of various diameters (0.1 and 0.15 cm) are used to model the soil.…”

“…Figure shows the final configuration of soil collapse simulated by proposed SPFEM. The final surface configurations and failure lines are compared with the experimental results and two numerical simulations (MPM and SPH ), as shown in Figure . All numerical results show a very similar response, and good agreement can be found between numerical and experimental results.…”

Numerical simulation of granular mixing in a rotary drum using a generalized interpolation material point method

“…The diameter of particles is 3 mm, and the filling ratio of the drum is 34%. For dry granular material, it is incompressible, so the cohesion strength is zero, and the dilatation angle is set to be ψ = 0° . A stacking test based on powder characteristic tester (BT‐1000, BETTERSIZE) shown in Figure was used to measure the friction angle, and it can be obtained that ∅ = 27°.…”

Multiscale modeling of large deformation in geomechanics

“…The friction coefficient between the base and the soil adopts a value of 0.4. This value plays a minor role for the entire collapse process since the main body of soil indeed flows over a thin layer adhering to the base . A symmetry boundary is assumed for the left side of the soil column.…”