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Paper 147

Numerical Simulations and Experimental Investigations of Contact Phenomena in a Mechanical Friction Clutch

J. Awrejcewicz and D. Grzelczyk
Department of Automation and Biomechanics, Technical University of Lodz, Poland

Keywords: clutch, friction, wear process, heat production, thermal phenomena, numerical simulations, experimental investigations.

full paper (pdf) - reference

A clutch belongs to elements of a mechanical system used for coupling shafts and transmitting torque between them. Historically, the oldest simple clutches were used for a direct connection of coaxial shafts. Future demands and tendencies in the technology of producing clutches made many requirements regarding their structure, functioning, strength or life. For this reason, appropriate knowledge of mathematical modelling and description of this system, as well as contact phenomena and tribological processes occurring therein, is important. These problems have been studied earlier, but only simplified mathematical models have been used and applied so far.

In this work numerical simulations and experimental investigations of the contact phenomena occurring on the contact surface of frictional shields of a mechanical friction clutch have been studied. The elasticity as well as wear properties of material of frictional shields rubbing themselves are taken into account. Moreover, numerical and experimental results are presented that describe thermal phenomena occurring in the considered system. The detailed mathematical description of wear processes and thermal phenomena in the mechanical friction clutch is presented in [1,2,3]. Computer simulations were obtained using numerical algorithms written in C++ and verified experimentally.

The goal of the experimental investigations carried out in the range of the work was confirmation of the proposed mathematical models describing the wear processes and thermal phenomena occurring in the mechanical friction clutch. In the results of the numerical and experimental studies both contact pressure and temperature distributions on the contact surface of the clutch linings have been determined, as well as changes of the friction torque transmitted by the clutch resulting from the change in the contact pressure distribution have been computed. Finally it has been shown, that the numerical simulations obtained agree with data obtained experimentally. It has been shown that decreasing of the friction torque transmitted by the clutch at a constant force pressing the discs or changes of the contact pressure distribution occur in accordance with the proposed mathematical model. The simple experimental qualitative verification of the model describing the thermal phenomena in the friction clutch studied indicates the relatively good qualitative conformity of the numerical solutions with the experimental results.

References

1
J. Awrejcewicz, D. Grzelczyk, "Modeling and analytical/numerical analysis of wear processes in a mechanical friction clutch", International Journal of Bifurcation and Chaos, 21(10), 2861-2869, 2011.
2
J. Awrejcewicz, D. Grzelczyk, "Modeling and analysis of thermal processes in mechanical friction clutch - numerical and experimental investigations", International Journal of Structural Stability and Dynamics. (to appear)
3
D. Grzelczyk, "Dynamics and tribological processes in a mechatronic system with a friction clutch", PhD Thesis, Technical University of Lodz, 2010.