Flexible shaker excitation signals for improved FRF estimation and and non-linearity assessment

In this paper, the use of advanced, flexible shaker excitation signals will be investigated with the aim (1) to obtain improved Frequency Response Function (FRF) estimations and (2) to assess the non-linearities of the excited system / structure. Pseudo-random and more general multisine signals rather than the more traditional pure or burst random signals will be used to increase the accuracy of the FRF estimate. Moreover, special multisine data acquisition and processing methods to identify the level of non-linearity will be illustrated by means of numerical simulation and real ground vibration testing on an aircraft scale model. The presented methods allow assessing the non-linearities at a single excitation level, which is in contrast to the more traditional method of repeating the test at multiple excitation levels and observing the FRF differences.