Energy transfer between acoustic fields by dry frictional contacts for SHM: Optimization of the high frequency vibration transfer
Résumé
This paper investigates the concept of transferring vibroacoustic energy from an ambient low-frequency
acoustic field towards a secondary high-frequency acoustic field, by exploiting the dry contact friction
nonlinearities. While low frequency oscillations allow for macroscopic sliding at the contact interfaces, the
consequent impacts and ruptures between asperities release elastic energy under the form of acoustic waves,
exciting the higher frequencies. High-frequency vibrations can allow the detection and localization of a
defect, as used in many structural health monitoring applications such as in aeronautic or civil engineering.
This article focuses on a device, called Secondary Acoustic Source (SAS), that generates high frequency
vibrations thanks to a rubbing contact. Firstly, the quantification of the vibration transfer is investigated.
Then the results of an experimental study, aimed to understand the cumulative behavior of multiple SAS,
transferring vibrations to the same structure, is presented. The objective is to increase the quantity of highfrequency
vibrations, generated from a certain available amount of low-frequency vibration energy (ambient
noise).