An enhanced dynamic force model of a type of small and soft McKibben-type pneumatic muscle (PM) actuator has been developed. This model takes the factor of external loads and a more sophisticated form of friction into account, and is presented as a polynomial function of pressure, contraction length, contraction velocity and external load. The coefficients in this model are determined from a se...

This paper aims at experimental and numerical investigation of springback behavior of sheet metals during Lbending process with emphasis on Stribeck-type friction modeling. The coefficient of friction in Stribeck curve depends on sliding velocity and contact pressure. The springback behavior of mild steel and aluminum alloy 6022-T4 sheets was studied experimentally and using numerical simulatio...

This paper presents a method for estimating Coulomb and viscous friction coefficients from responses of a harmonically excited dual-damped oscillator with linear stiffness. The identification method is based on existing analytical solutions of non-sticking responses excited near resonance. The method is applicable if the damping ratio of viscous component can be considered small. The Coulomb an...

The dry frictional contact between two solid surfaces is well known to obey Coulomb friction laws. In particular, the static friction force resisting the relative lateral (tangential) motion of solid surfaces, initially at rest, is known to be proportional to the normal force and independent of the area of the macroscopic surfaces in contact. Experimentally, the static friction force has been o...

A linear complementarity formulation for dynamic multi-rigid-body contact problems with Coulomb friction is presented. The formulation, based on explicit Euler integration and polygonal approximation of the friction cone, is guaranteed to have a solution for any number of contacts and contact con guration. A model with the same property is formulated for impact problems with friction and nonzer...

The most often used friction model for sheet metal forming simulations is the relative simple Coulomb friction model. This paper presents a more advanced friction model for large scale forming simulations based on the surface change on the micro-scale. The surface texture of a material changes if two surfaces are in contact under a normal load which is an effect of flattening due to normal load...

The most often used friction model for sheet metal forming simulations is the relative simple Coulomb friction model. This paper presents a more advanced friction model for large scale forming simulations based on the surface change on the micro-scale. The surface texture of a material changes when two surfaces are in contact under a normal load. This is caused by flattening due to combined nor...

Unlike the well known Amontons-Coulomb laws of dry friction, the recent precise experimental studies of low velocity friction dynamics provide sensitive tests for a theoretical description. We introduce a model, in which the friction force originates from multistability induced by interactions of individual pairs of asperities whose properties undergo a slow time evolution due to plastic creep ...

The Savage-Hutter (SH) avalanche model is a depth-averaged dynamical model of a fluid-like continuum implementing the following simplifying assumptions: (i) density preserving, (ii) shallowness of the avalanche piles and small topographic curvatures, (iii) Coulomb-type sliding with bed friction angle delta and (iv) Mohr-Coulomb behaviour in the interior with internal angle of friction phi> or =...

In this paper, the effects of friction compensation, including exact compensation, undercompensation and overcompensation, in PD controlled 1DOF mechanical systems are investigated. The friction force that is acting on the mechanical system and the friction compensation term in the feedback loop are described by a class of discontinuous friction models consisting of static, Coulomb and viscous ...