EXPERIMENTAL AND NUMERICAL INVESTIGATIONS ON RESONANT CHARACTERISTICS OF A SINGLE-LAYER PIEZOCERAMIC PLATE AND A CROSS-PLY PIEZOLAMINATED COMPOSITE PLATE

摘要

Piezolaminated composite plates are widely used in many industrial applications such as intelligent structures and advanced aerospace structural applications. To improve the dynamic performance of the piezolaminated composite structures, it is necessary to experimentally investigate the resonant characteristics of these structures. Three measurement techniques are used in this study to investigate the vibration behavior of the tested specimen. The first method, AF-ESPI (amplitude-fluctuation electronic speckle pattern interferometry) is the major technique for measuring the resonant characteristics of a single-layer piezoceramic plate and a multilayer cross-ply GFRP (glass fiber reinforced plastics) piezolaminated composite plate for completely free conditions. The completely free condition is approximated in experiment by placing and partially sticking the specimen on the surface of a very soft sponge. A thin single-layer piezoceramic plate is first investigated and up to the twenty-sixth transverse modes are presented. Excellent quality of interferometric fringe patterns for vibration mode shapes are presented. The second method, LDV (laser Doppler vibrometer), and the third method, impedance analyzer, are both employed to verify the AF-ESPI results for the piezolaminated composite plate. Both in-plane and out-of-plane resonant frequencies and vibration mode shapes of the piezolaminated composite plate are demonstrated. Finally, numerical computations based on the finite element analysis are presented for comparison with the experimental results. Excellent agreement between the measured data and the numerical results is found in resonant frequencies and mode shapes for the single-layer piezoceramic plate and the cross-ply piezolaminated composite plate.