Kinetic friction during dry sliding along atomistic-scale Al 001 /Al 001 and -Al2O3 0001 / -Al2O3 0001 interfaces has been investigated using molecular dynamics MD with recently developed Reactive Force Fields ReaxFF . It is of interest to determine if kinetic friction variations predicted with MD follow the macroscopic-scale friction laws known as Coulomb’s law for dry sliding and Stokes’ fric...

To study how macroscopic friction phenomena originate from microscopic junction laws, we introduce a general statistical framework describing the collective behavior of a large number of individual microjunctions forming a macroscopic frictional interface. Each microjunction can switch in time between two states: a pinned state characterized by a displacement-dependent force and a slipping stat...

This paper reports the first direct measurements of static friction force and interfacial shear strength between silicon (Si) nanowires (NWs) and poly(dimethylsiloxane) (PDMS). A micromanipulator is used to manipulate and deform the NWs under a high-magnification optical microscope in real time. The static friction force is measured based on "the most-bent state" of the NWs. The static friction...

the aim of this article is study of tool plunge depth (tpd) effects on mechanical properties of friction stir welding of aa1100 aluminium alloy to a441 aisi steel. for this purpose the 0.1, 0.2, 0.4, and 0.6 mm tpd selected and other welding parameters kept constant. the results shows that the frictional heat increases and stir zone grain size decreases with increasing tpd at both base metals. ...

Friction and wear are part and parcel of all walks of life, and for interfaces that are in close or near contact, tribology and mechanics are supremely important. They can critically influence the efficient functioning of devices and components. Nanoscale friction force follows a complex nonlinear dependence on multiple, often interdependent, interfacial and material properties. Various studies...

The importance of machining process in today’s industry requires the establishment of more practical approaches to clearly represent the intimate and severe contact on the tool-chipworkpiece interfaces. Mathematical models are developed using the measured force signals to relate each of the tool-chip friction components on the rake face to the operating cutting parameters in rough turning opera...

We describe a new methodology that enables dynamical control of motion through modulating the friction at coating surfaces by exposing to UV light. The principle is based on reversible switching of the surface topographies of the coating by light. The coating surface transfers from flat in the dark to corrugated in the presence of UV by forming regular ridge-like line gratings. Both the static ...

FRICTION AND LUBRICATION in sheet metal forming are influenced by such parameters as material properties, surface finish, temperature, sliding velocity, contact pressure, and lubricant characteristics. The parameters that affect friction and lubrication are schematically shown in Fig. 7.1. Depending on these parameters, the performance of a lubricant and the coefficient of friction (COF) vary. ...

12.7-mm thick plates of 6061-T6511 aluminum alloy and high hardness steel (528 HV) were successfully joined by a friction stir bonding process using a tungsten Process parameter variation experiments, which geometry, plunge and traverse rates, tool offset, spindle tilt, and rotation speed, were conducted to develop a parameter set which yielded a defect free joint. Laboratory tensile tests exhi...

Based on focused ion beam and shear friction apparatus data, the multi-resolutions (0.2 nm–5 μm) volume roughness & asperity contact (VR & AC) three-dimensional structure on principle slip surface interface-surface (PSS-IS) is measured on high performance computational platform; and physical plastic-creep friction model is established by using hybrid hyper-singular integral equation & lattice B...