Energy transfer between acoustic fields by dry frictional contacts for SHM: a lumped numerical analysis

This paper investigates the concept of transferring / pumping vibroacoustic energy from an ambient acoustic field towards a secondary acoustic field by exploiting the dry contact friction nonlinearities. The secondary acoustic field could be used, for instance, as a reference signal in structural health monitoring with various applications e.g. in aeronautics. Firstly the concept of energy dissipation by dry friction is examined for a nonlinear model of a simplified spring-mass-damper-dry friction damper system. A Masing macroslip contact model is introduced. The dynamic behavior of the system is calculated using a combination of a nonlinear Newmark method and a Newton-Raphson iterative method. The three different contact states (stick, stick/slip and slip) and peak flattening are observed. The analysis is further extended to a more complex system constituted by 3 degrees of freedoms and a frictional slider. The vibrational energy transfer between the different natural frequencies of the system and the exploitation of the ambient vibrational field are both investigated and demonstrated in numerical simulation results.