Measurement of Slider/Disk Collision Forces Using Acoustic Emission Source Wave Analysis

A new measuring technique has been developed for the purpose of analyzing the slider/disk collision phenomena. Very small piezoelectric sensors are mounted on the slider. These sensors detect elastic waves (acoustic emission) in the slider which are induced by the collisions at the slider rail surface. In order to obtain input collision force quantitatively, the transfer function of the slider, sensor, and electric circuit is measured by the breaking pencil lead method. The inverse operation is also performed by using source wave analysis. Force amplitude of the order of 4˜20 mN and contact time of the order of 5˜22 μ are detected. Two types of collision force are observed. One has large amplitude and narrow time width and is conjectured to arise from collisions with hard projections. The other has small amplitude and wide time width and is conjectured to arise from collisions with soft projections. Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conferenc...