TY - EJOU
AU - Schwarz, Brian
AU - McHargue, Patrick
AU - Richardson, Mark
TI - ODS \& Modal Testing Using a Transmissi- bility Chain
T2 - Sound \& Vibration
PY - 2018
VL - 52
IS - 2
SN - 2693-1443
AB - In this paper, we show how Operating Deflection Shapes (ODS’s) and mode shapes can be obtained experimentally from measurements that are made using *only two sensors* and *two short wires* to connect them to a multi-channel acquisition system. This new test procedure is depicted in Figure 1. Not only is the equipment required to do a test much more cost effective, but this method can be used to test *any sized test article*, especially large ones.

The testing method introduced here involves moving a pair of sensors along together in a prescribed manor, and calculating the Transmissibility between them. The resulting chain of Transmissibility’s is then postprocessed to obtain a *single reference set* of cross-channel measurements, from which ODS’s and mode shapes can be extracted.

A *“round trip”* example is used to show how an original set of modal parameters can be recovered by curve fitting a *single reference set* of output-only Cross spectra, and a *single reference set* of FRFs.
KW - Fourier spectrum (DFT)
KW - Auto power spectrum (APS)
KW - Cross power spectrum (XPS)
KW - Frequency Response Function (FRF)
KW - Operating Deflection Shape (ODS)
KW - Experimental Mode Shape (EMA Mode)
KW - Opera- tional Mode Shape (OMA Mode)
KW - Modal Assurance Criterion (MAC)
KW - Shape Difference Indicator (SDI)
DO - 10.32604/sv.2018.03637