Flextensional actuators consist of a piezoceramic bonded to a flexible structure that amplifies and changes the direction of generated piezoceramic displacement. In this work, some prototypes of novel flextensional actuators designed by using topology optimization are manufactured, and characterized. Experimental resonance frequencies and displacements of each flextensional actuator and single piezoceramic are obtained by using an impedance analyzer and laser interferometry technique, respectively. The main purpose of these measurements is to verify the displacement amplification introduced by new designs of flextensional piezoelectric actuators. To verify the amplification, both displacements of the single piezoceramic and the complete actuator are measured through laser interferometry and compared. The measurements are made considering harmonic and transient excitations. All experimental results are compared with finite element simulations, using ANSYSTM software. The predicted amplification rates provided by these actuators are verified. Therefore, these results validate flextensional actuators designed by using topology optimization.

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Multi-actuators piezoelectric devices consist of a multi-flexible structure actuated by two or more piezoceramic portions, whose differing output displacements and forces are tailored according to the excitation properties of the piezoceramic materials and the desired working locations and directions of movement. Such devices have a wide range of application in performing biological cell manipulation, for microsurgery, and in nanotechnology equipment, and the like. However, the design of multi-flexible structures is a highly complex task since the devices have many degrees of freedom and, employ a variety of piezoceramics, but must carefully tune the movement coupling among the device parts to prevent motion in undesirable directions. In prior research, topology optimization techniques have been applied to the design of devices having minimum movement coupling among the piezoceramic parts, and in this work a number of these devices were manufactured and experimentally analyzed to validate the results of the topology optimization. X-Y nanopositioners consisting of two piezoceramic portions were addressed and designs considering low and high degrees of coupling between desired and undesirable displacements were investigated to evaluate the performance of the design method. Prototypes were manufactured in aluminum using a wire EDM process, and bonded to piezoceramics (PZT5A) polarized in the thickness direction and working in d31 mode. Finite element simulations were carried out using the commercial ANSYS software application. Experimental analyses were conducted using laser interferometry to measure displacement, while considering a quasi-static excitation. The coupling between the X-Y movements was measured and compared with FEM results, which showed that the coupling requirements were adequately achieved.

Laser interferometry is a well-established technique for the characterization of piezoelectric actuators. In this work, by using a low cost Michelson interferometer, the measurement of the calibration factor and the displacement amplification of a novel piezoelectric flextensional actuator (PFA), designed by using the topology optimization method, is performed. A simple method, based on small phase modulation depth when the PFA is driven by a triangular waveform, allows the absolute interferometer calibration. The free-displacement of the PFA for various drive voltages is measured and the displacement amplification is determined. The linearity and frequencyresponse of the PFA are evaluated up to 20 kHz

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