Modal sensing of circular cylindrical shells using segmented piezoelectric elements

In this computational study, we investigate the use of thin piezoelectric films to detect the vibration of circular cylindrical shells. Rather than use complicated sensor shapes for modal filtering, we consider simple rectangular shapes and leave the measurement filtering and reconstruction of the system dynamics to full order modal observers. Simulations indicate that decreasing the magnitude of the real part of the observer gain leads to slower convergence but to the desired mode. Larger values lead to faster convergence but to the actual sensor measurements, indicating the occurrence of minimal signal filtering. Increasing the number of sensors can improve observer performance provided that they are placed intelligently on the shell. If a sensor cannot adequately detect the mode which it was intended to sense, sensor output cancelation may affect the behavior of all modal observers. In addition to the signal measurement analysis, the contribution of different mode types within different frequency bands is also investigated, as well as the determination of an adequate number of vibrational modes to include in the simulations.