Effects of Normal Pressure, Sliding Velocity and Moisture Content of Chickpeas on Dynamic Friction Coefficient on Steel Surfaces

In this research, an apparatus was made and utilized to determine the friction coeffi-cient of chickpea grains on steel surfaces. Experiments were carried out on two black and galvanized surfaces and at four sliding velocities of ۵, ۲۰, ۱۰۰ and ۵۰۰ mm/min, at three moisture content of ۷.۵%, ۱۵% and ۲۱% wet basis (w.b.) and at three vertical pressure values of ۱۴.۲۸, ۱۰۰ and ۱۵۰ kPa. The following results were obtained. ۱) For surface conditioning, the steel plates need to be passed through the grains for at least ۷ times. ۲) At low sliding velocity, by increasing the velocity from ۵ to ۲۰ mm/min, the dynamic friction coefficient of chickpea grains increased, and at a sliding velocity of ۵۰۰ mm/min it was decreased. ۳) For the black steel surface, by increasing the moisture content of chickpea grains from ۷.۵% to ۱۵% w.b., the value of the friction coefficient in-creased; but at a moisture content of ۲۱% w.b., it decreased. For galvanized steel sur-faces, and sliding velocities of ۵ and ۲۰ mm/min, increasing the moisture content, the value of friction coefficient was found to decreased, but for sliding velocities of ۱۰۰ and ۵۰۰ mm/min it’s behaviour was similar to the black steel surface. ۴) Normal pressure has no significant effect on the friction coefficient (at ۰.۰۱ level) and the difference between the mean values of the coefficient of friction associated with the normal pressure of ۱۴.۲۸ kPa and ۱۰۰ kPa, as well as ۱۰۰ kPa and ۱۵۰ kPa was not significant at the ۰.۰۵ signifi-cance level.

کلیدواژه ها:

Chickpea ، Apparatus ، Friction coefficient