An experimental research on three-dimensional waves in a concrete panel

Abstract- An experimental verification of three-dimensional waves is performed in a concrete panel. Frequencycontrolled method is applied to guided wave experiments to induce the central frequency as high as 25 kHz in the concrete panel. The measured acceleration waveforms are transformed into spectrograms with the joint timefrequency analysis. A mode identification method is developed to find the induced wave modes. Several wave modes on the lower branches are identified on a group velocity-frequency plot by comparing to the predictions of theoretical dispersive group velocity curves. The wave modes on the lower branches with simple displacement profiles are easily induced and detected in the guided wave experiments. Keywords: Three-dimensional wave, frequency-controlled method, mode identification, joint time-frequency analysis 1.