Knowledge of the tribology of human skin is essential to improve and optimize surfaces and materials in contact with the skin. Besides that, friction between the human skin and textiles is a critical factor in the formation of skin injuries, which are caused if the loads and shear forces are high enough and/or over long periods of time. This factor is of particular importance in bedridden patie...

This study evaluated the effects of physical characteristics and geologic factors on the shear strength of compacted sands from Wisconsin that are used as granular backfill for mechanically stabilized earth walls and reinforced soil slopes. Physical properties and shear strength were determined for 30 compacted sands collected from a broad range of geological deposits. Relationships between str...

Here, we have utilized Lateral Force Microscopy (LFM) based mechanical pushing of micro/nano-objects to study adhesion and friction characterization at the micro/nanoscale. Continuum micro/nano-friction models for particle rolling, spinning and sliding cases are discussed for general particle-substrate interfaces. A rolling resistance model using the Double-Hertz model is devoloped for such gen...

Many stick insects and mantophasmids possess tarsal 'heel pads' (euplantulae) covered by arrays of conical, micrometre-sized hairs (acanthae). These pads are used mainly under compression; they respond to load with increasing shear resistance, and show negligible adhesion. Reflected-light microscopy in stick insects (Carausius morosus) revealed that the contact area of 'heel pads' changes with ...

Wepresent results from laboratory experiments and anumericalmodel for frictional weakening and shear localization. Experiments document strain localization in sheared layers at normal stresses of 0.5 to 5MPa, layer thicknesses of 3 to 10mm, and imposed slip velocities of 10 to 100 μm/s. Passive strain markers and the response to load perturbations indicate that the degree of shear localization ...

A simple approach for the bulk production of carbon nanoscrolls (CNSs) is described. This method is based on the application of shear-friction forces to convert graphite nanoplatelets into carbon nanoscrolls using a bi-axially oriented polypropylene (BOPP) surface. The combined action of shear and friction forces causes the exfoliation of graphite nanoplatelets and the simultaneous roll-up of g...

For H-type transition to turbulence in a flat-plate boundary layer, we identify dynamically important features resulting from direct numerical and large eddy simulations (DNS and LES, respectively). Even though LES coupled with a dynamic subgrid-scale model provides an accurate prediction of the transition location, it fails to predict initial overshoot and subsequent turbulent skin friction. D...

Using equilibrium and nonequilibrium molecular dynamic simulations, we found that engineering the strain on the graphene planes forming a channel can drastically change the interfacial friction of water transport through it. There is a sixfold change of interfacial friction stress when the strain changes from -10% to 10%. Stretching the graphene walls increases the interfacial shear stress, whi...

Discontinuous shear thickening (DST) observed in many dense athermal suspensions has proven difficult to understand and to reproduce by numerical simulation. By introducing a numerical scheme including both relevant hydrodynamic interactions and granularlike contacts, we show that contact friction is essential for having DST. Above a critical volume fraction, we observe the existence of two sta...

[1] We have applied a thin-shell modeling technique to study the neotectonics of the Caribbean plate. Kinematic conditions computed assuming rotation poles and velocities from NUVEL-1A and from recent geodetic studies have been applied at the lateral boundaries of the model to represent the motion of the adjacent plates with respect to the Caribbean. We have generated a large number of models v...