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...

Friction at the nanoscale has revealed a wealth of behaviours that depart strongly from the long-standing macroscopic laws of Amontons-Coulomb. Here, by using a 'Christmas cracker'-type of system in which a multiwalled nanotube is torn apart between a quartz-tuning-fork-based atomic force microscope (TF-AFM) and a nanomanipulator, we compare the mechanical response of multiwalled carbon nanotub...

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 ...

Friction modeling and identification is a prerequisite for the accurate control of electromechanical systems. This paper considers the identification and control of friction in a high load torque DC motor to the end of achieving accurate tracking. Model-based friction compensation in the feedforward part of the controller is considered. For this purpose, friction model structures ranging from t...

Friction characterization is a prerequisite for an accurate control of electromechanical systems. This paper considers the identification and control of friction in a high load torque DC motor to the end of achieving accurate tracking. In the first place, model-based feedforward controllers for friction compensation are considered. For this purpose, friction model structures ranging from the cl...

Abstract—This study presents a procedure for friction calculation of column electric power steering (C-EPS) system which affects handling and comfort in driving. The friction losses estimation is obtained from experimental tests and mathematical calculation. Parts in C-EPS mainly involved in friction losses are bearings and worm gear. In the theoretical approach, the gear geometry and Hertz law...

This paper presents a linear programming based approach for the design of controllers for rest-to-rest manoeuvres of vibratory systems subject to friction. A multiple spring mass system is considered in the development where friction and control input forces act on the same mass. The result of the linear programming is a control profile for rest-to-rest manoeuvres where the static and Coulomb f...

one of the great challenges in the processing of materials using equal channel angular pressing (ecap) is the high forming forces required to produce large shear deformation in the material. researchers show that the friction forces between the die and the sample constitute a great part of the total forming forces. recently, ultrasonic vibrations are successfully implemented into the ecap proce...