The sliding interfaces found in the body— within the eyes, the digestive system, and the articulating joints, for example—are soft and permeable yet extremely robust, possessing low friction. The common elements among these systems are hydrophilic biopolymer networks that provide physical surfaces, elasticity, and fluid permeability. Stiff, impermeable probes are traditionally used to assess th...

failure of the quay walls due to earthquakes results in severe economic loss. because of hazards threatening such inexpensive nodes of national and international transportation networks, seismic design of quay walls is still an evolving topic in marine structural engineering. this study investigates the sensitivity of the gravity-type quay wall stability respect to uncertain soil and seismic pr...

The friction force on the moving interface between two different vacuum states of superfluid 3He is considered at low temperature. Since the dominating mechanism of the friction is the Andreev reflection of the massless " relativistic " fermions, which live on the A-phase side of the interface, the results are similar to that for the perfectly reflecting mirror moving in the quantum vacuum.

Finite Element Analysis (FEA) based techniques have become increasingly available to simulate metal cutting process and offer several advantages including prediction of tool forces, distribution of stresses and temperatures, estimation of tool wear, optimization of cutting conditions, tool edge geometry and coatings, and determination of residual stresses on machined surfaces. However, accuracy...

This paper presents a methodology to determine simultaneously (a) the flow stress at high deformation rates and temperatures that are encountered in the cutting zone, and (b) the friction at the chip–tool interface. This information is necessary to simulate high-speed machining using FEM based programs. A flow stress model based on process dependent parameters such as strain, strain-rate and te...

High cycle fatigue failure of turbine and compressor blades due to resonance in the operating frequency range is one of themain problems in the design of gas turbine engines. To suppress excessive vibrations in the blades and prevent high cycle fatigue, dry friction dampers are used by the enginemanufacturers. However, due to the nonlinear nature of friction contact, analysis of such systems be...

Large cyclic movements between the femoral stem and bone during the first weeks after total hip arthroplasty may hamper bone ingrowth and adversely affect the eventual success of the arthroplasty. Little is known, however, about the magnitude of the motions and its relationship to design and surgical factors. A two-dimensional finite element model of a cementless prosthesis inserted into the pr...

The main challenge in predicting sliding friction is related to the complexity of highly nonequilibrium processes, the kinetics of which are controlled by the interface temperature. Our experiments reveal a nonmonotonic enhancement of dry nanoscale friction at cryogenic temperatures for different material classes. Concerted simulations show that it emerges from two competing processes acting at...

An experimental study was conducted to measure the static friction coefficient under constant normal load and different interface conditions. These include surface roughness, dwell time, displacement rate, as well as the presence of traces of lubricant and wear debris at the interface. The static friction apparatus includes accurate measurement of friction, normal and lateral forces at the inte...

During the early stages of orthodontic treatment, the self-ligating system is more efficient because a reduction of friction in the interface archwire-bracket occurs. The friction is determined by three components: friction, binding and notching; it depends on the critical contact angle defined, for each pair of wire and brackets, where they contact in two diametrically opposite slotâ€TMs points.