Elimination of support effects in modal testing

In modal testing, the measured Frequency Response Functions (FRFs) are often inaccurate due to the adverse mechanical effects, such as mass-loading effects of transducers, shaker-structure interaction and the support effects. This paper investigates removing the support effects from measured FRFs using dynamic substructure method. Both stiffness and damping are considered in the support conditions. The validity of the method is proved in a simulated modal testing. It is shown that with the given support conditions the affected FRFs can be corrected provided that some additional driving point and transfer FRFs concerned with the support point are also measured. Finally, performance of this method is assessed with noisy measured data. Simulation shows that 1% white noise is acceptable in the proposed correction method.