The amplitude-dependent defect of the elastic modulus was calculated for the 3 main dislocation hysteresis models. These were the Granato-Lücke breakaway hysteresis, the Davidenkov hysteresis, and friction hysteresis without a restoring force. The ratio of the amplitude-dependent decrement to the modulus defect was considered for all 3 types of loop, and it was shown that the ratio generally depended upon the vibration amplitude. In the particular case of a power-law amplitude, the ratio did not depend upon the amplitude but only upon the exponent. Expressions were obtained for the ratio-exponent relationships for the 3 hysteresis-loop types, and it was demonstrated that the ratio could serve to identify the loop shape. A comparison of calculated curves with available experimental data showed that most of them lay closer to the Davidenkov and zero restoring-force hystereses. An analysis was made of the applicability of the secant modulus-defect approximation which was used to deduce dislocation strain from internal friction measurements.

Amplitude-Dependent Elastic-Modulus Defect in the Main Dislocation-Hysteresis Models. A.B.Lebedev: Fizika Tverdogo Tela, 1999, 41[7], 1214-21 (Physics of the Solid State, 1999, 42[7], 1105-11)