Papers by Keyword: Friction Coefficient (FC)

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Authors: I.G. Gorycheva, Alexey G. Shpenev
Abstract: In this paper the problem for a periodic structure punch sliding upon a viscoelastic layer bonded to a rigid half space is considered. The semi-analytical solution of the problem is developed. Influence of incompressible fluid in the gap between two bodies upon friction force, contact size and pressure distribution is analysed. The obtained model can be used in a number of practical applications, for example in accounting of automobile tire aquaplaning upon wet road surface.
Authors: Yuh Ping Chang, Jeng Haur Horng, Te Chuan Ho, Chun Jen Huang
Abstract: Not only fatigue of the metal materials but also inferior quality of the lubricant oils will be occurred for the machines after the long-term operation. Therefore, the self-developed reciprocating friction tester with the measurement system was used to experimental study the tribological properties for the automobile oil regeneration in this study. The major parameters are the reciprocating speeds and the three types of the oil. The ball specimens were made of SUJ2 and the plate specimens were made of SUS304. The variations of friction coefficient and electrical contact resistance were simultaneously recorded during dynamic friction process. After each friction test, the OM was used to observe the worn surface. According to the experimental results, the differences between the new oil, the old oil and the regeneration oil can be clarified. The viscosity, density and color were quite similar for the old oil and the regeneration oil. However, the tribological properties of the regeneration oil were significantly improved. Moreover, it also showed stable during the dynamic friction tests. Even compared with the new oil, the regeneration oil sometimes showed better lubrication under the operation conditions. The wear resistance of the regeneration oil does show great potentials.
Authors: N. Donnelly, M. McConnell, Denis P. Dowling, J.D. O'Mahony
Authors: Miriam Kupková, Martin Kupka, Emőke Rudnayová, Ján Dusza
Abstract: Irregular evolution of friction coefficient, recorded during the ball-on-disc test on Si3N4 based ceramic materials, was analysed by means of fractal geometry methods. Tests were carried out at room temperature, in air and without any lubricant. It was proven that the friction coefficient trace, considered as a geometric object, has the property of a fractal curve. The fractal dimension of this curve increased with increasing wear rate measured in a corresponding wear test. This could indicate the possible correlation between the wear rate and the fractal dimension of friction coefficient as a function of sliding distance (time).
Authors: Xin Wu Ma, Guo Qun Zhao, Wen Juan Li
Abstract: A new method for determination of friction coefficient in sheet metal forming of Mg alloy AZ31B is presented in this paper. The method is based on the bulging test of sheet metal in which the specimen is processed with a hole at the center. The diameter of the hole will increase along the stroke of the punch and the dimensional change of the hole has a certain relationship with the friction coefficient at the punch/specimen interface. Thus, the friction coefficient can be determined indirectly according to the dimension of the hole in the bulging process. The bulging process of the sheet is simulated using FE code DEFORM-2D. The analysis model is set up according to the experiment of the bulging and the friction calibration curves are generated from the simulations of the bulging by setting different coefficients of friction. The friction coefficient can be determined by measuring the hole dimension during the bulging process and comparing it with the friction calibration curves.
Authors: Fen Lin
Abstract: Road friction coefficient is a critical component in traffic safety. The estimation of tire–road friction coefficient at tires allows the control algorithm in vehicle activity system to adapt to external driving conditions. This paper develops a new tire–road friction coefficient estimation algorithm based on tire longitudinal force estimation and tire slip estimation. Vehicle tire longitudinal forces are estimated by sliding mode observer combined with Kalman filter. Based on the tire forces estimation, road friction coefficient is estimated by recursive least squares algorithm (RLS). The test conditions which contain different friction level road are established in ADAMS/Car. The conclusions validate the reliability and efficiency of the proposed method for estimating the friction coefficient in different adhesion level roads. The research also indicates the theory of slip slope can also be reappeared in virtual experiment based on ADAMS.
Authors: Zhen Ying Huang, Hong Xiang Zhai, Ming Xing Ai
Abstract: The tribological behavior of a new cermet Ti3AlC2/Cu was experimentally investigated. The results showed that the Ti3AlC2/Cu was a good tribological material sliding against the low carbon steel, especially for a high sliding speed. The friction coefficient was as low as 0.13 ~ 0.15, and the Ti3AlC2/Cu wear rate was only 3.4×10-6 mm3/Nm, for the sliding speed of 60 m/s and the normal pressure of 0.8 MPa. The forming of a frictional film consisted of Ti, Al, Cu and Fe oxides on the friction surfaces could be a fundamental cause.
Authors: Le Wang, Bin Tang, Yuan Yang Zhao
Abstract: The paper presents a comprehensive friction model of reciprocating compressor which is able to evaluate friction losses in moving parts. The model consists of crankshaft, connecting rod and piston all supported by bearings as well as the piston ring/cylinder interface viewed as sliding friction. Hydrodynamic lubrication theory reveals relationship between load and friction coefficient and was demonstrated to be helpful to give insight to the lubrication characteristics of journal bearing. The model gave the composition of friction losses, friction coefficient dynamic change with orbiting angle and effect of oil viscosity on compressor performance. The results showed that the friction losses of piston ring/cylinder interface and the rod big end bearing was most part of the friction losses and it was necessary to choose suitable oil viscosity to reach the optimum compressor performance.
Authors: Xuan Rong Xin, Cheng Song He, Long Long Shan
Abstract: A new measurement of friction coefficient which is more applicable to overload extrusion technology is proposed in this paper. It determines the friction coefficient of overload plastic forming by firstly determining the load mutation of friction by a floating die experimental device. It is proved in this experiment that the friction coefficient in extrusion process can be precisely determined and the effectiveness of lubricating can be evaluated objectively by this new method which is easier to understand and master than the theory that determines the friction coefficient by ring upsetting.
Authors: Luca Crema, Giovanni Lucchetta
Abstract: In injection molding of highly filled polymers, such as plastic-bonded hard ferrite, mold life decreases significantly due to wear and surface damage. This deterioration process leads to lower accuracy concerning the surface finish and the dimensional and geometric tolerance of the molded bonded magnets. In this work, the wear of a steel mold caused by the molding of a plastic-bonded ferrite magnet has been studied with the aim of determining the main wear factors. Furthermore, two different surface treatments have been tested, namely gas nitriding and DLC superlattice coating. Friction and wear induced by part de-molding was investigated by means of tribological pin-on-disc tests. The results of such experiments were analyzed in terms of loads, surface roughness evolution and surface investigations by means of Scanning Electron Microscope observations.
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