Abstract: An apparatus for controllably delivering power from a device to a workpiece is useful, for example, in performing qualitative material tests on various materials. In the instant apparatus, a sonic generator means controllably supplies sonic power to a workpiece, causing the surface of the workpiece to erode. A sensing means produces an actual power signal having a magnitude responsive to the power consumed by the sonic generator means. A settable means produces a desired power signal, and a control means compares the desired and actual power signals and supplies motor control signals in response to the respective magnitudes of the power signals and to a tracking time interval signal. In response to termination of the tracking time signal, the control means blocks the motor control signals. A motor means controllably moves the sonic generator means relative to the workpiece in response to receiving the motor control signals.

Abstract: High modulus asperities are incorporated into a fluoroelastomer-polyacrylate elastomer matrix to provide a material which, when cured, exhibits high, stable coefficients of friction over a wide temperature range.

Abstract: A friction coupling which utilizes a friction plate composed of high modulus asperities incorporated into a reboundably compressible elastomeric matrix for selective rotational engagement with a relatively noncompressible reaction plate between which is directed a flow of fluid with the asperities hydrodynamically wedging such fluid into a relatively thin load supporting film between the asperities and the reaction plate which film absorbs substantially all of the energy of engagement in the shearing effect of the fluid during relative rotation of the plates.