An ultrasonic technique for determining the elastic constants of glass wafers

A technique is described that determines the elastic constants for a glass wafer (or a wafer of any homogeneous, isotropic, elastic solid) by standing it on edge on two piezoceramic transducers and using pulses to excite resonant contour-mode vibrations in the wafer. One transducer excites the wafer into vibration with a grated sine wave and the second transducer senses when the wafer is driven at a resonant frequency by monitoring the decay transient of the pulsed resonant vibration. For a 10 cm (four inch) diameter wafer of 7740 glass, the resonances are in the range of 25 to 50 kHz. The application of the technique to determining the values of the elastic constants of Corning 7740 glass over the temperature range from -50 to 100°C is described