The Effects of Stingers on Receptance Function Measurements

Abstract

When using a shaker to conduct receptance function measurements, it is usual to put a stinger between the shaker and a force transducer that is attached to a test structure. Ideally, a stinger can transmit desired axial force to excite the structure and isolate excitations in all other DOFs in order not to bias the testing results. The selections of stingers were made by trial-and-error, by chance, or by experience. This may cause test errors especially when the magnitude of receptance function of the excitation system is significant compared with that of the structural system at the correspondent frequency. In this work, substructure synthesis algorithm was used to calculate the effects of stingers on the receptance function measurements. The dynamic characteristics of a shaker, a shaker suspension system, a stinger, and a test structure were considered in the analysis. If the shaker is fixed, the method can predict the effects of the stinger on measured receptance functions. Finally, a cantilever beam and seven different sizes of stingers were used to verify this method. Good agreements were found between the predictions and testing results.