A finite element program based on elastic –plastic model of Mohr-Coulomb criterion was used to evaluate the bearing capacity coefficients of soil under shallow strip flexible footing . The results were compared with others’ analytical results and it was found that the present study could offer quite consistent and rather precise values for the bearing capacity coefficients . The effect of d...

This paper analyses the problem of modelling joint friction in robotic manipulators with gear transmissions at joint velocities varying from close to zero until their maximum appearing values. It is shown that commonly used friction models that incorporate Coulomb, (linear) viscous and Stribeck components are inadequate to describe the friction behaviour for the full velocity range. A new frict...

The application of a dual relay feedback approach towards the identification of frictional effects in servo-mechanisms will be presented in this paper. The friction model, thus identified, will consist of Coulomb (including possibly directional Coulomb or load bias) and viscous friction components, both of which can be automatically extracted from suitably designed relay experiments. At the sam...

We consider a widely used higher order glacier flow model with a variety of parameterizations of wall slip, including Coulomb friction, regularized Coulomb friction laws and a power law. Mathematically, the Coulomb friction problem is found to be analogous to a classical friction problem in elasticity theory. We specifically analyze the case in which slip is possible everywhere at the boundary,...

This report presents a new way to model and identify single-link flexible arms when Coulomb friction is present in the joint. In order to isolate the effects of this nonlinearity, the arm model is divided into two submodels: motor and beam. The two anm coupled through the torque at the base of the beam. A systematic method is developed to obtain the dynamics of a lumped-mass flexible beam, and ...

The simulation of granular particles in a quasi-two-dimensional container under vertical vibration as an experimental accessible model for granular gases is performed. The velocity distribution function obeys an exponential-like function during the vibration and deviates from the exponential function in free-cooling states. It is confirmed that this exponentiallike distribution function is prod...

Analysis and theoretical comparison between several fixed point strategies and Uzawa algorithms (for classical and augmented Lagrangian) are performed to solve the so called Signorini problem with Coulomb friction without any regularization. Thanks to a formalism coming from convex analysis, some new fixed point strategies are presented and compared to already known methods. The analysis is fir...

Coulomb friction is inevitable in every mechanical system with contact motion. When the mechanical system with Coulomb friction is under feedback control, it can destabilize the system by generating limit cycles. Controlled mechanical systems with ideal Coulomb friction can be viewed as a particular class of relay feedback systems characterized by the zero DC gain property and the positivity of...

Friction, which evidently appears in any mechanical systems incorporating parts with relative motion, manifests itself as material nonlinearity. Depending on its application, friction can be a desirable thing or a drawback in the system. In order to optimally utilize or compensate for the frictional effect in a system, characterization of the frictional behaviour is very crucial. The classical ...