Effect of mechanical quality factor on pulse-switching semi-active vibration control and stability analysis

Semi-active pulse switching vibration control technique and stability analysis is studied in this paper. Piezoelectric elements are used to vibration control in this technique. These elements are connected to an electrical shunt circuit containing an inductance and an electronic switch. The switch triggers on the extremums of the system displacement or voltage signal of the piezoelectric elements when the electrostatic energy stored on piezo-electrodes is maximum. In the case of harmonic excitation, it´s easy to find the extremums of displacement or voltage signal, but in the case of random excitations, finding the best extremums for switch triggering is difficult. Therefore, the voltage or displacement signal is analyzed during a given time window and the statistically probable displacement or voltage-level threshold is determined from both the average and standard deviation of the signal, to find the best extremums for switching on. The stability analysis of the pulse switching control technique and effect of the mechanical quality factor on the performance of this technique is studied. The numerical results show a significant decrease in vibration energy of the system and also demonstrate that this technique is completely stable.