In this letter, non-linearity and energy localization are experimentally tuned in an electromagnetic vibration energy harvester in order to enhance its output performances. The non-linear device consists of two moving magnets guided by elastic beams and coupled by a repulsive magnetic force. The mechanical non-linearity is introduced by considering large displacements of the beams and the energy localization is achieved by mistuning the mass of one of the moving magnets. The critical load resistance is determined experimentally in order to tune the non-linearity level and to drive the harvester beyond its critical amplitude. Consequently, the performances of the device, in terms of harvested power only from the perturbed dof oscillator and frequency bandwidth, are enhanced respectively up to 19.4% and 116% compared to the performances of the non-linear periodic system.

This work aims at increasing the performance prediction for acoustic propagation systems that will operate in the presence of the inevitable parameters uncertainty. In the present contribution, the finite element method is applied to solve an acoustic problem described by the Helmholz equation...

The brake squeal reduction has been extensively investigated in many academic and industrial researchers. Friction-induced vibrations can be considered as a dynamic instability problem. Generally, automotive engineers and researchers working in the domain of disk brake noise treat instabilities due to the force of friction as a friction-induced vibration. In the case of squeal noise, mode coupling may cause instability of the system. The aim of this article is to propose a minimal two degree of freedom disk brake model in order to investigate the effects of different parameters on mode-coupling instability. This model takes into account self-excited vibration, gyroscopic effect, friction-induced damping, and brake pad geometry. Thus, a stability analysis of equilibrium by calculating complex eigenvalues is presented to investigate the influence of the main parameters on the stability zone such as the opening angle of the brake pad and preload. For the validation of the stability analysis, squeal index and time domain response are used. The results obtained show the importance of optimizing the physical and geometrical parameters of the brake and that some of these parameters have greater effects compared to the others to reduce noise.