Abstract
This work deals with limitations encountered in measuring the dynamic characteristics of structural systems. Structural loading and response are measured by transducers that are characterized by multiple resonant frequencies where peaks occur in the magnification factor of their transfer function. The transfer function of a transducer is the ratio of the Fourier transform of its output to the Fourier transform of the input causing that output. The magnification factor of the transfer function of a transducer is the factor by which its zero-frequency response must be multiplied to determine the magnitude of its steady-state response at any given frequency.
The presence of multiple peaks in the transfer function of a transducer indicates a potential for problems when the transducer responds to a transient stimulus. The problem is more severe if the stimulus contains significant amplitude at frequencies near these peaks; distortion of the recorded signal will occur.
If the transfer function of the transducer is completely characterized, data distortion can be corrected by an inverse treatment. This inverse problem consists of determining the corresponding excitation associated with a particular system model and a given response. Even though measurement difficulties encountered when using transducers with multiple resonant peaks are not generally solvable by an inverse treatment, procedures are described in this work which can be applied on a frequency-selective basis to acquire valid data.
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This work was supported by the United States Department of Energy.
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Walter, P.L., Nelson, H.D. Limitations and corrections in measuring structural dynamics. Experimental Mechanics 19, 309–316 (1979). https://doi.org/10.1007/BF02324151
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DOI: https://doi.org/10.1007/BF02324151