Structural traveling waves have potential applications in numerous areas such as propulsion and skin friction drag reduction. Recent research has shown that via the two-mode excitation method, traveling waves can be generated in both one- and two-dimensional structures via the use of low-profile piezoelectric actuators. Traveling waves on a one-dimensional beam propagate in a single direction, while those on a two-dimensional structure, such as a plate, do not necessarily propagate uniformly across the surface. The propagation patterns can include unidirectional traveling waves with spatial phase shifts, wave fronts moving in opposing directions, or even rotationally moving waves. These propagation patterns depend on the participating modes and vary based on the excitation frequency, thus if multiple frequency traveling waves are generated on a plate, multiple propagation patterns are superimposed. In this study, traveling waves were generated in a plate at two different frequencies. Those frequencies were then simultaneously excited on the plate to generate a propagation pattern containing traveling waves at both frequencies. The superimposed propagation pattern was then analyzed by comparing it with a numerical combination of the individual frequency patterns. The experimentally superimposed traveling waves were found to be a linear combination of the individual frequency waves. In addition, by combining multiple frequency waves, the percentage of the plate containing traveling waves increased.
Patrick F. Musgrave, V. V. N. Sriram Malladi, and Pablo A. Tarazaga, "Investigation into the superposition of multiple mode shape composed traveling waves," Proc. SPIE 10164, Active and Passive Smart Structures and Integrated Systems 2017, 1016408 (Presented at SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring: March 26, 2017; Published: 11 April 2017); https://doi.org/10.1117/12.2260323.
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