| Abstrakt: |
Suspensions and supports generate forces of the same magnitude as the driver. Structural inhomogeneities also have a considerable effect on the frequency response of a vibrator. They introduce additional resonances and antiresonances and dispersion curves like fluctuations in the frequency response curve. Their effect usually depends on the degree of symmetry of the driver point relative to the vibrator and their distance from the driven point. For instance, a mass at the driver reduces drastically the high frequency response of a vibrator, whereas a mass, a few bending wavelengths away from a driver, has only a relatively small effect on the response curve. In many instances, the presence of inhomogeneities, their magnitude, and position can be analyzed from the frequency response of the vibrator. A spherical shell, when driven at its weld (equator), has a response that is about 10 dB lower than when driven at its pole. A number of typical example curves are computed, or measured, and discussed in this paper. [Work supported by ONR 474.] [ABSTRACT FROM AUTHOR] |
