Left figure: A rotary-shear, intermediate- to high-velocity frictional testing machine

Normal load is applied using an air-driven actuator (10 kN max.) to a pair of cylindrically shaped specimens. Torque is measured with a torque-gage, which is placed next to the specimen of the stationary side. This machine is equipped with a servo-motor, reduction gears, and electromagnetic clutches to control the input motor speed, which enables to produce slip rates in terms of equivalent slip velocities V, as defined in Shimamoto and Tsutsumi (1994), in a range from V = 2.6 mm/s to 1.3 m/s for a cylindrical specimen of 25 mm in diameter. Change in the slip velocity during sliding can be introduced either by changing the input rotation of the motor or by shifting the gear trains by the use of electromagnetic clutches.

Right figure: A rotary-shear frictional testing machine equipped with a liquid medium pressure vessel.

Normal load is applied either by using an oil-driven actuator (20 kN max.) from the bottom or by a gear-train system from the top of the machine to a pair of cylindrically shaped specimens. This machine is equipped with a servo-motor, reduction gears, and electromagnetic clutches to control the input motor speed, which enables to produce slip rates in terms of equivalent slip velocities V, as defined in Shimamoto and Tsutsumi (1994), in a range from V = 3 x 10^-6 mm/s to 3 mm/s for a cylindrical specimen of 25 mm in diameter. Change in the slip velocity during sliding can be introduced either by changing the input rotation of the motor or by shifting the gear trains by the use of electromagnetic clutches.

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