Impedance Modeling of Modal Exciters
"Impedance Modeling of Modal Exciters"
This paper describes a simple Multiple-Input-Multiple-Output (MIMO) testing procedure for developing an impedance model of modal exciters. This method can be used at the test site: before, during and/or after the test. The impedance model describes the current/voltage input to the exciter to the force/displacement output of the exciter. The method uses a simple back-to-back testing method where two exciters are characterized simultaneously. One exciter provides the boundary condition for the other exciter and vice versa. These impedance models can be used to evaluate the health of the exciter and to determine it's response to impedance loading of the fixture and the structure being tested. The influence of the exciter amplifiers, sensors and acquisition systems which are used in the modal testing are also characterized. Several examples are used to illustrate the usefulness of this method in evaluating the exciter systems used in modal testing.
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