Effects of Shaker Test Set Up on Measured Natural Frequencies and Mode Shapes

The shaker set up used for modal testing can have an effect on the measured characteristics obtained. Several test setup configurations are presented to show the effects on the measured response of the system due to single shaker vs. multiple shakers as well as stinger types. For reference, impact testing is also performed to remove any effects from the shaker stinger/setup that might affect the results. Modal assurance criteria between several configurations are presented to illustrate the dramatic differences that can be obtained due to the test set up used.