Investigation on vibration mitigation methodology with synergistic friction and electromagnetic damping energy dissipation

Friction dampers are widely used in vibration control of mechanical and civil architectures as a highly robust contact-based energy dissipation strategy. The energy dissipation principle of electromagnetic dampers is to convert the mechanical energy of vibration into electrical energy through a mechanical-magnetic-electric coupling mechanism and dissipate it through an external load circuit or store it in a battery or capacitor. It should be noted that the frictional energy dissipation is displacement dependent, while the electromagnetic energy dissipation is velocity dependent; hence, a synergistic energy dissipation with a combination of frictional and electromagnetic elements can be implemented to obtain satisfactory vibration suppression. This work presents a bi-stable energy scavenging inspired dynamic vibration absorber (DVA) consisting of negative stiffness spring components, electromagnetic conversion elements and friction pairs. The multiple periodic inter-well motion and chaotic motion are understood to illuminate the efficient energy shunt contributed by the bi-stable mechanism. The effects of mass ratio, potential barrier height and friction force on the energy scavenging and vibration suppression performance of this proposed prototype are parametrically analyzed. Numerical simulations have found that the bi-stable DVA with small mass ratio has a significant attenuation effect on the vibration energy of the host structure excited by harmonic excitation or transient shocks. The results indicate that an increase in the barrier height of the bi-stable oscillator leads to an increase in the optimal mass ratio required to achieve optimal energy dissipation efficiency. The small mass ratio bi-stable damper can achieve the best vibration suppression performance by actively regulating the friction force according to the change of ambient vibration. In addition, it is evident that the presence of critical friction minimizes the vibration displacement and energy of the host structure. However, when the friction force exceeds the critical threshold, the dynamic response of the host structure is amplified and the vibration energy increases, which is not conducive to vibration control. Therefore, implementing an appropriate friction force can improve the devastating dynamic response of the structure and facilitate the conversion of vibration energy into available energy.