– After thrown onto a solid substrate, very soft spherical gels bounce repeatedly. Separate rheological measurements suggest that these balls can be treated as nearly elastic. The Hertz contact deformation expected in the static (elastic) limit was observed only at very small impact velocities. For larger velocities, the gel ball deformed into flattened forms like a pancake. We measured the siz...

Electro-mechanical actuators including planetary roller screw (PRS) support cyclic loads in aeronautical conditions. PRS multiple thread contacts between screw, rollers and nut allow the mechanism to large loads. However, accreditation requires fine prediction of fatigue lifespan. In this paper, a design strategy for mechanisms is proposed combining Hertz contact model multi-axial criterion. Th...

The equations governing the motion of steel balls and their impact onto shell liners in industrial Semi-Autogenous Grinding (SAG) mills are derived in full details by the authors and are used in order to determine the effective design variables for optimizing the working conditions of the mill and to avoid severe impacts which lead to the breakage of SAG mill shell liners. These design vari...

The nonlinear energy sink (NES) is defined as a single-degree-of-freedom structural element with relatively small mass and weak dissipation, attached to primary structure via essentially coupling. It passive dissipation device designed rapidly absorb vibration (due shock, blast, earthquakes, etc.) from locally dissipate it. article contains mini-review of the works on NESs. Design schemes for s...

The study of granular matter is of interest for fundamental physics as well as for technological applications. The intensive studies of liquids and solids gave physicists powerful tools for investigating these states of matter. These tools are, however, very difficult to apply to granular matter @1#. Little work has been done on sound propagation in real granular media. Experiments have been pe...

Contact problems are central to Solid Mechanics, because contact is the principal method of applying loads to a deformable body and the resulting stress concentration is often the most critical point in the body. Contact is characterized by unilateral inequalities, describing the physical impossibility of tensile contact tractions (except under special circumstances) and of material interpenetr...