A calibration process is developed to determine the parameter values. Three-axial compressions tests in laboratory and neural network are used to determine the material internal friction angle and stiffness, respectively. These tests are repeated numerically using PFC models with different sets of particle friction coefficients and particle stiffness values. Three-axial compressions tests are f...

It can be said that lubricants are used to reduce the friction between rubbing surfaces. This is done by separating the moving surfaces with a film of the lubricant, thereby replacing the friction of the metal to metal surfaces by the internal friction within the lubricant itself. Lubricants also act as a cooling agent to carry away heat generated by friction or conducted to the bearing surface...

slope instability due to landslides is particularly common in iran. it is possible to fight against these hazards thanks to the roots of trees, which provide an important contribu-tion towards the stability of hillslopes. however, our knowledge of the effectiveness of roots for slope stability needs improvement. therefore this study was carried out on the effect of tree roots on slope stability...

We investigate the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before it increases and saturates to a value that depends on the roughness of the sliding surface. We use an index-matched interstitial liquid to probe the internal motion of the gr...

Particles larger than a component's internal clearances are not necessarily dangerous. Particles the same size as the internal clearance cause damage through friction. But the most dangerous particles in the long-term are those that are smaller than the component's internal clearances. Particles smaller than 5 microns are highly abrasive. If present in sufficient quantities, these invisible 'si...

Bolted joints are prevalent in most assembled structures; however, predictive models for their behavior do not exist. Calibrated models, such as the Iwan model, are able to predict the response of a jointed structure over a range of excitations once calibrated at a nominal load. The Iwan model, though, is not widely adopted due to the high computational expense of implementation. To address thi...

Hearing starts when sound-evoked mechanical vibrations of the hair-cell bundle activate mechanosensitive ion channels, giving birth to an electrical signal. As for any mechanical system, friction impedes movements of the hair bundle and thus constrains the sensitivity and frequency selectivity of auditory transduction. Friction is generally thought to result mainly from viscous drag by the surr...