Vibration characteristics of composite piezoceramic plates at resonant frequencies: Experiments and numerical calculations

The experimental measurement of the resonant frequencies for the piezoceram ic material is generally performed by impedance analysis. In this paper, we employ an optical interferometry method called the amplitude-fluctuation e lectronic speckle pattern interferometry (AF-ESPI) to investigate the vibra tion characteristics of piezoceramic/aluminum laminated plates; The AF-ESPI is a powerful tool for the full-field, noncontact, and real-time measureme nt method of surface displacement for vibrating bodies. As compared with th e conventional film recording and optical reconstruction procedures used fo r holographic interferometry, the interferometric fringes of AF-ESPI are pr oduced instantly by a video recording system. Because the clear fringe patt erns measured by the AF-ESPI method will be shown only at resonant frequenc ies, both the resonant frequencies and corresponding vibration mode shapes are obtained experimentally at the same time. Excellent quality of the inte rferometric fringe patterns for both the in-plane and out-of-plane vibratio n mode shapes are demonstrated. Two different configurations of piezocerami c/aluminum laminated plates, which exhibit different vibration characterist ics because of the polarization direction, are investigated in detail. From experimental results, we find that some of the out-of-plane vibration mode s (Type A) with lower resonant frequencies cannot be measured by the impeda nce analysis; however, all of the vibration modes of piezoceramic/aluminum laminated plates can be obtained by the AF-ESPI method. Finally, the numeri cal finite element calculations are also performed, and the results are com pared with the experimental measurements. Excellent agreements of the reson ant frequencies and mode shapes are obtained for both results.