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J Rajchenbach

Publications and source records attributed to J Rajchenbach.

14 recordsLinked to original sources
PubMed2001

Stress transmission through textured granular packings.

We propose a theoretical approach aimed to describe the stress transmission through granular pilings. According to our framework, the stress transmission obeys a diffusive process in random isotropic packings, while it follows a local convection-diffusion equation in textured packings characterized by an anisotropic distribution of the contact orientations. In the latter case, the direction of the convection depends on the angular distribution function of the contact orientations. Our theoretical approach agrees with both experimental and numerical recent evidences, and moreover, succeeds in capturing the role of the pile preparing history.

Journal Article↗
PubMed2000

Stress transmission through a model system of cohesionless elastic grains

Understanding the mechanical properties of granular materials is important for applications in civil and chemical engineering, geophysical sciences and the food industry, as well as for the control or prevention of avalanches and landslides. Unlike continuous media, granular materials lack cohesion, and cannot resist tensile stresses. Current descriptions of the mechanical properties of collections of cohesionless grains have relied either on elasto-plastic models classically used in civil engineering, or on a recent model involving hyperbolic equations. The former models suggest that collections of elastic grains submitted to a compressive load will behave elastically. Here we present the results of an experiment on a two-dimensional model system--made of discrete square cells submitted to a point load--in which the region in which the stress is confined is photoelastically visualized as a parabola. These results, which can be interpreted within a statistical framework, demonstrate that the collective response of the pile contradicts the standard elastic predictions and supports a diffusive description of stress transmission. We expect that these findings will be applicable to problems in soil mechanics, such as the behaviour of cohesionless soils or sand piles.

Journal Article↗