Amplitude-dependent Losses Research Articles

Measurement of low values of internal friction at elevated temperatures

Some features are described of an apparatus which measures internal friction of longitudinally resonant specimens at elevated temperatures. The apparatus uses electrostatic drive and frequency-modulation detection, and operates near 100 kc/s, at temperatures up to 1300? C. Limits of operation are discussed, and a comparison made of the observed amplitude-dependent loss at the specimen supports with a simple theory of frictional loss.