Accession Number : AD0634745

Title :   FOURIER-TRANSFORM TECHNIQUE FOR MEASURING TERMINATING IMPEDANCES.

Descriptive Note : Technical rept.,

Corporate Author : MINNESOTA UNIV MINNEAPOLIS DEPT OF AERONAUTICS AND ENGINEERING MECHANICS

Personal Author(s) : Plunkett, R. ; Wittig,L. E.

Report Date : 1964

Pagination or Media Count : 27

Abstract : The mechanical impedance of a foundation depends, in part, on the characteristics of the column attached to it. For this reason it is important to have a technique to find that mechanical impedance with the column in place; this requirement rules out direct measurement with an impedance head. This study was made to determine the usefulness of a transient loading technique for measuring the mechanical impedance of a complex termination. The method determines the impedance at the end of an elastic bar from the Fourier Transforms of pulse shapes in the bar. Experimental results for a simple termination show that this technique can be used to measure the impedance of a lumped parameter system. However, comparison between transient loading measurements and direct measurements with an impedance head for a more complex termination show that not enough frequency information can be obtained to determine its impedance accurately enough. (Author)

Descriptors :   (*RODS, VIBRATION), (*INTEGRAL TRANSFORMS, MEASUREMENT), LOADS(FORCES), SHEAR STRESSES, STRAIN(MECHANICS), FREQUENCY, ELASTIC PROPERTIES, MECHANICAL WAVES

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE