Influence of a Strong Low-Frequency Wave on the Propagation of Weak Ultrasonic Pulses in a Rod Resonator Made of Annealed Polycrystalline Copper

An experimental study of an influence of a strong low-frequency wave on the propagation of weak ultrasonic pulses in an acoustic resonator made of annealed polycrystalline copper has been carried out. The measurements were carried out with harmonic excitation of the resonator at its first four longitudinal modes in the range from 2 to 15 kHz, the frequency of ultrasonic pulses varied from 65 to 400 kHz. The analysis of the observed nonlinear effects was carried out within the framework of the polycrystal equation of state obtained on the basis of a modified string model of the Granato-Lucke dislocation. The values of the parameters of dissipative and reactive nonlinearity of dislocations in annealed copper are determined.