This work is devoted to the analysis of elasto-plasticity models arising in soil mechanics. Contrary to the typical models mainly used for metals, it is required here to take into account plastic dilatancy due to the sensitivity of granular materials to hydrostatic pressure. The yield criterion thus depends on the mean stress and the elasticity domain is unbounded and not invariant in the direc...

Experiments have shown that when a horizontal cylinder rotates around the vertical axis in a granular medium, the drag force in the stationary regime becomes independent of the depth, in contradiction with the frictional picture stipulating that the drag should be proportional to the hydrostatic pressure. The goal of this study is to understand the origin of this depth independence of the granu...

The burst strength of rotary compressor pressure vessel directly affects the safety. Therefore, it is mandatory to ensure the strength of the pressure vessel. Major factors that determine the burst pressure of pressure vessel are stress concentration around the suction and discharge hole as well as its shape and thickness. In this study, stress concentration of the pressure vessel is investigat...

Molecular dynamics simulations were carried out to investigate the pressure dependence of homogeneous defect nucleation behavior in bcc Mo. The crystal was sheared on the ð1 10Þ 1⁄211 1 slip system under different confining pressures. The defect nucleation stress was found to increase as the confining pressure increases. Dislocation loop was nucleated when sheared under hydrostatic compression,...

Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in ...

Bulk properties of open cell polyurethane foam are studied in a hydrostatic compression experiment under strain control. A linear region of behaviour is observed in the stress-strain curve, followed by a non-monotonic region corresponding to a negative incremental bulk modulus. The bulk modulus in the linear region is in reasonable agreement with the value calculated from compressional Young’s ...

In Incremental Sheet Forming (ISF) strains can be obtained well above the Forming Limit Curve (FLC) that is applicable to common sheet forming operations like deep drawing and stretching. This paper presents an overview of mechanisms that have been suggested to explain the enhanced formability. The difference between fracture limit and necking limit in sheet metal forming is discussed. The neck...

Our present work presents a direct association of the observed loss of shear strength in boron carbide under plane shock wave compression to amorphization in boron carbide under triaxial stress compression. This evidence is obtained from in-situ measurement of Raman, and infrared vibrational spectra of boron carbide confined in a Diamond Anvil Cell (DAC) under hydrostatic and non-hydrostatic pr...

In petroleum industry, during production, the vertical effective stress in the reservoir increases as the pore pressure decreases from few hundreds to few tens bar; in average the horizontal effective stress increases as well, but at a lower rate along an oedometric path, favoring shear stress and reservoir depletion; a complex geology induces locally a variety of stress paths between the two e...

BACKGROUND/AIMS Mechanical forces are thought to induce cellular responses through activation of signalling pathways. Cells within the intraocular environment are exposed to constant changes in the levels of intraocular pressure. In this study, an attempt was made to determine the acute effects of elevated hydrostatic pressure on different intraocular cells grown in culture. METHODS Different...