Abstract
In the interests of determining the complex elastic constants of a given material (aluminum alloy) over a wide frequency range, the frequency and Q of a large multitude of overtones of a long (3-m), thin (12-in. diameter) bar were measured. These include the longitudinal mode and torsional mode. The frequency range covered was from about 0.5 kc to 100 kc. The elastic constants λ and μ are found to be relatively independent of frequency. The dispersion curve is in reasonable agreement with the Pochhammer-Chree equations for an infinite bar. The Q of the longitudinal mode decreases from about 260 000 at the lowest frequency to 140 000 at the highest.
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