Development of an apparatus for the direct measurement of traction coefficients for lubricants; preliminary measurements from a bouncing ball apparatus

摘要

The concept of a direct measurement bouncing ball apparatus for the determination of the traction coefficients of lubricants at high pressures and shear rates under impact conditions is outlined. Two basic forms of apparatus are described, one in which a ceramic impact plate is mounted on a structure with high stiffness in the normal direction and low stiffness tangentially, with the impact forces being measured by strain gauges, and another in which the impact plate is mounted above a piezo-electric transducer capable of measuring simultaneously the force components. The problems encountered with the dynamic response of the system under the severe impact conditions involved are outlined. Some preliminary results for the response of a representative are presented.