Papers by Keyword: Piezoelectric Material

Abstract: The properties of piezoelectric materials due to the effect of electrical, mechanical, thermal, radiation, and chemical parameters are systematized. On the basis of Maxwell's relations (obtained from expressions for thermodynamic functions) and the application of the system analysis methodology, it made it possible to develop an analytical model of the relationship between the parameters and properties of piezoelectrics in the form of a system of equations. The results of the metrological analysis of an analytical model, which made it possible to identify the sources of additional errors in the measurement of parameters, to derive formulas for their calculation, which in turn contributes to an increase in the accuracy of measurements of the piezoelectrics parameters and products based on them, are presented.

Abstract: This work investigates the complete analytical solution for functionally graded material (FGM) plates incorporated with smart material. The odjective of the present work is to determine bending characteristics of piezoelectric FGM plates with different geometrical parameters, voltages and boundary conditions for electro-mechanical loading. In this work an analytical formulation based on higher order shear deformation theory (HSDT) is presented for the piezoelectric FGM plates. The solutions are obtained in closed from using Navier’s technique for piezoelectric FGM plates a specific type of simply supported boundary conditions and pc code have been developed to find out the deflections and stresses for various parameters. All the solutions are plotted against aspect proportion, side to thickness proportion as a function of material variety parameter (n) and thickness coordinate for different voltages. The significant trends from the results are obtained.

Abstract: In this paper, an interaction integral is applied to evaluate the crack-tip field intensity factors for piezoelectric cracks by using BEM. Based on this, the fracture parameters for different crack configurations and loading conditions are analyzed in details for both the center crack and edge crack problem. According to the present results, the path-independent behavior of the interaction integral is verified. The comparison of the I-integral results with those by the J-integral and the displacement interpolating methods shows a good agreement.

Abstract: Polymeric poly (vinyliden fluoride) (PVDF) is nontoxic. It possesses a better mechanical flexibility and requires a lower synthesis temperature, as compared to the piezoceramic counterparts. In order to achieve a competitive advantage against the current piezoelectric sensor, graphite could replace a more expensive silver-palladium as the electrodes for the piezoelectric PVDF. This paper reports the preliminary results on the synthesis of steel-supported graphite-PVDF/PVDF/graphite-PVDF composite films using the two-step process, consisted of the electrophoretic deposition (EPD) and heat treatment. The composite films were characterized by means of the optical microscopy, scanning electron microscopy, X-ray diffraction and differential scanning calorimetry. The heat treated graphite-PVDF electrode deposited by EPD provides adequate mechanical strength for the subsequent depositions of pure PVDF layer and the second layer of graphite-PVDF composite electrode. However, the final heat treatment stage did not eliminate the fine and large cracks of the composite film, which might be attributed to high residue stresses and weak bonding between graphite and PVDF particles in the post-heat treated composite films. Nevertheless, the increase in final heat treatment temperature of the composite film at Stage 3 improved the graphite and PVDF grain alignment, as well as its crystallinity.

Abstract: ZnO nanostructures were synthesized by two wet-chemical methods (hydrothermal and electrochemical) featuring low temperature (95°C) and atmospheric pressure onto nonwoven substrates. We investigated a hydrothermal method using reagents Zn (NO₃)₂.6H₂O and hexamethylenetetramine (HMTA) as well as an electrochemical method using ZnCl₂, and KCl containing electrolyte with H₂O₂ and/or O₂ bubbling. The surface condition of substrate material and the experimental conditions played a key role in the nanowire formation. The morphologies observed by scanning electron microscopy (SEM) include wurtzit or cabbage-like. These morphologies were found to vary with the method applied.

Abstract: Electroactive polymers (EAP) are relatively soft and flexible materials, easy to integrate and able to undergo large deformations by applying an electric field (usually some 10 V/μm). This coupling between strain and electric field (quadratic by nature) as well as particular mechanical properties have already been used advantageously to design actuators. As energy harvesters, EAP have also shown good abilities by providing energy densities up to 0.4 J/g/cycle (generator integrated in a shoe). Moreover, they present some advantages over other techniques as electromagnetic or piezoelectric as they have low resonance frequency response and high elasticity which enable them to be used in situations where large displacements are available. The main drawback of EAP as energy harvesters is that they don't experience direct coupling between strain and electric field, such as the piezoelectric effect. It is therefore essential to use an external electrical polarization source in order to create energy cycles induced by the EAP capacitance variations when it is subject to external stress. The goal of this work is to combine the EAP and piezoelectric materials using the advantages of both, for a hybrid energy harvesting. Different possible configurations and their performances are studied and a comparison with existing techniques is made.

Abstract: Piezoelectric materials possess really high potential to deliver nanoscale or micro-scale positioning resolution, huge blocking force, and fast response; hence they are widely utilized in a variety of engineering applications and product designs. However, a higher and unacceptable positioning error always occurs due to the hysteresis effect of the piezoelectric materials. For high-precision applications, this natural behavior should be eliminated. For solving this problem, a nonlinear control design based on concepts of Bouc-Wen model, system identification, and the proportional-integral-derivative (PID) control design is proposed. The proposed control design can be divided into the following four steps: 1. Input and output behaviors of piezoelectric materials are firstly mathematically described with Bouc-Wen model, 2. System parameters in Bouc-Wen model for representing the characteristics of piezoelectric materials then simultaneously identified with respect to practical input and output data of piezoelectric materials, 3. Stability verification for this identified Bouc-Wen model should be done in the next, and 4. A PID control is elegantly derived finally via minimizing the tracking error performance index and is practically realized for nanoscale tracking design. One important contribution of this investigation is that the tracking error between output displacement of mathematical modeled piezoelectric materials and desired trajectory can be proven to exponentially converge to zero.

Abstract: This article determine the wheel load on the role of piezoelectric vibrator in the way as the low-frequency vibration force through analyzing the wheel load, and the loading frequency is 10Hz;in this paper, combining with asphalt roadbed structural response, we get that the piezoelectric conversion device that between the above layer and the middle layer generate optimal performance adopting the theoretical calculation, a single piezoelectric vibrator can generate the electricity by a 2.62 mJ, what provides a theoretical support for the pavement performance of the piezoelectric material.

Abstract: The numerical simulation and experimental method are adopted to analyze the piezoelectric vibration control of the simplified autobody beam structure. The autobody beam structure is simplified as a beam fixed at both ends. The finite element model of beam structure with piezoelectric patches is established. The static analysis and modal analysis is conducted by the piezoelectric analysis of the finite element analysis software. The proportional and proportional-derivative control methods are studied in the piezoelectric active vibration control analysis for the simplified beam structure. The experimental system is established to obtain the vibration control effectiveness of the beam structure. The experimental results show that the type of two ends patching beam has more effective vibration control ability than the central patched beam.

Abstract: The finite element method is adopted to simulate the piezoelectric vibration control of the body thin-wall structure. The finite element model of piezoelectric laminated structure which is formed by attaching piezoelectric layer to the autobody thin-wall structure is established. The static analysis and modal analysis is condudted by the piezoelectric analysis of the finite element analysis software. The proportional control method is studied in the piezoelectric active vibration control analysis for the autobody thin-wall structure. The active vibration control effectiveness according to different structural parameters is analyzed and the influence rules of structural parameters are concluded.