Techno Press
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Coupled Systems Mechanics   Volume 4, Number 4, December 2015, pages 279-295
DOI: http://dx.doi.org/10.12989/csm.2015.4.4.279
 
Modeling of the friction in the tool-workpiece system in diamond burnishing process
J.T. Maximov, A.P. Anchev and G.V. Duncheva

 
Abstract     [Full Text]
    The article presents a theoretical-experimental approach developed for modeling the coefficient of sliding friction in the dynamic system tool-workpiece in slide diamond burnishing of low-alloy unhardened steels. The experimental setup, implemented on conventional lathe, includes a specially designed device, with a straight cantilever beam as body. The beam is simultaneously loaded by bending (from transverse slide friction force) and compression (from longitudinal burnishing force), which is a reason for geometrical nonlinearity. A method, based on the idea of separation of the variables (time and metric) before establishing the differential equation of motion, has been applied for dynamic modeling of the beam elastic curve. Between the longitudinal (burnishing force) and transverse (slide friction force) forces exists a correlation defined by Coulomb\'s law of sliding friction. On this basis, an analytical relationship between the beam deflection and the sought friction coefficient has been obtained. In order to measure the deflection of the beam, strain gauges connected in a \"full bridge\" type of circuit are used. A flexible adhesive is selected, which provides an opportunity for dynamic measurements through the constructed measuring system. The signal is proportional to the beam deflection and is fed to the analog input of USB DAQ board, from where the signal enters in a purposely created virtual instrument which is developed by means of Labview. The basic characteristic of the virtual instrument is the ability to record and visualize in a real time the measured deflection. The signal sampling frequency is chosen in accordance with Nyquist-Shannon sampling theorem. In order to obtain a regression model of the friction coefficient with the participation of the diamond burnishing process parameters, an experimental design with 55 experimental points is synthesized. A regression analysis and analysis of variance have been carried out. The influence of the factors on the friction coefficient is established using sections of the hyper-surface of the friction coefficient model with the hyper-planes.
 
Key Words
    diamond burnishing; tool-workpiece system; slide friction coefficient; geometric nonlinearity; dynamic deflection; strain gage measurement
 
Address
J.T. Maximov, A.P. Anchev and G.V. Duncheva: Technical University of Gabrovo, Department of Applied Mechanicas, 5300 Gabrovo, Bulgaria
 

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