Traveling Wave Generation on a Clamped, Thin Plate with Flush-Mounted Piezoelectric Actuators

Piezoelectric actuators are widely used for the nano/micro positioning and adjustment systems. In the paper, the investigation on the oscillations of contacting surfaces of the piezoelectric thick-walled cylinder is presented. Piezoelectric cylinder is the main component of piezomechanical system named as piezo-screw and is used to turn the screw. This investigated piezomechanical system can be used for the precise positioning with a high resolution (less than 50 nanometers). Piezoelectric cylinder has radial polarization. Traveling-wave oscillations of the second circumferential modal shape (n = 2, m = 1) are excited. Three different electrode topologies are used to drive the screw. Electrodes are grouped into upper and low groups in both topology cases. Each group consists of six electrodes where positions of corresponding electrodes in upper and lower group are shifted by π/6. Numerical investigation of the traveling wave oscillation is performed and dependencies oscillation trajectories of contact surfaces on excitation schemes are determined when three different electrode topologies are used. Dependency of oscillations of contacting points upon length of the actuator is analyzed as well. Advantages and disadvantages of each excitation case are discussed.

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Evaluation of Hidden Corrosion in a Thin Plate Using a Non-Contact Guided Wave Technique

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.321-323.492 ◽

2006 ◽

Vol 321-323 ◽

pp. 492-496 ◽

Cited By ~ 5

Author(s):

Ik Keun Park ◽

Tae Hyung Kim ◽

Hyun Mook Kim ◽

Yong Kwon Kim ◽

Yong Sang Cho ◽

...

Keyword(s):

Ultrasonic Wave ◽

Thin Plate ◽

Guided Waves ◽

Wave Generation ◽

Guided Wave ◽

Thickness Reduction ◽

Thin Plates ◽

Depth Measurement ◽

Mode Cutoff ◽

Hidden Corrosion

In this paper, study on evaluation of thickness reduction in a thin plate with guided waves is presented. Ultrasonic guided wave techniques have been widely studied and successfully applied to various non-destructive tests with the advantage of long range inspection. In addition to application of guided waves to NDT, non-contact methods for ultrasonic wave generation and detection have become very useful and well combined with guided wave techniques due to their capability of ultrasonic wave generation and reception in surface of high temperature or on rough surface. An advanced non-contact technique for detection of thickness reduction simulating hidden corrosion in thin plates using guided waves is proposed. The proposed approach uses EMAT(Electro-Magnetic Acoustic Transducer) for the non-contact generation and detection of guided waves in aluminum plates. Interesting features of the dispersive behavior in selected wave modes are used to detect plate thinning. The experimental results show that the mode cutoff measurements provide a qualitative measurement of thinning detects and change in the mode group velocity can be used as quantitative parameter of thinning depth measurement.

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