Generation and propagation of ultrasonic plate wave in fluid-loaded porous polymeric membrane

In this work, the generation and propagation of ultrasonic leaky plate waves in polymeric membranes used in separations is demonstrated. Polymeric membranes are critical components in many chemical processes. An experimentally measured time-domain signal was examined using the time frequency representation (TFR) or spectrogram calculated using the short time Fourier transform (STFT). Spectrograms of the plate wave and a reference signal in water are shown. The spectrograms show the dispersive characteristics of the plate wave. This result provides a basic demonstration of propagation of the plate waves in these materials. A potential method for process monitoring and quality control for these materials is demonstrated.