A METHOD FOR MEASURING THE DEPENDENCE OF INTERNAL-FRICTION ON STRAIN

A new method for investigating possible increases of internal friction when a sample is subjected to a substantial constant strain is discus sed here. A special beam oscillator was designed in which the orientat ion of the apparatus determines whether the gravitational torque will apply either a large constant strain or a negligible one. The method w as applied to test the strain dependence of the internal friction of a steel flexure 2.0 cm in length and 0.5 mm in thickness. When bent thr ough an angle of 14.5-degrees, it exhibited an 18% increase in interna l friction over its unstrained value.