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 discussed here. A special beam oscillator was designed in which the orientation of the apparatus determines whether the gravitational torque will apply either a large constant strain or a negligible one. The method was 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 through an angle of 14.5°, it exhibited an 18% increase in internal friction over its unstrained value.