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Photoluminescence and piezoelectricity investigation of La1.98Nd0.02Ti2O7, Sm1.98Ce0.02Ti2O7 and Er1.98Gd0.02Ti2O7 multifunctional materials

Öztürk Esra, Sarilmaz Ebru

Materials Science Poland

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2019

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Vol. 37, No. 4

607--614

EN

Nd³⁺ doped La₂Ti₂O₇, Ce⁴⁺ doped Sm₂Ti₂O₇ and Gd doped Er₂Ti₂O₇ have been synthesized at different reaction temperatures using solid state reaction method, and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA), thermogravimetric analysis (TG). Excitation spectra, emission spectra and decay time curves of the samples were investigated by photoluminescence spectrophotometer (PL) and typical transitions of rare earth ions were observed. Dielectric properties, piezoelectric properties and Curie temperature of the obtained luminescent materials were measured for electrical characterization. The results showed that all materials have both photoluminescent and piezoelectric properties and show high Curie temperature.

2

Numerical Modelling of a Piezo Roof Harvesting System. The Right Component Selection

Leo R. di, Viscardi M., Tuccinardi F. P., Visone M.

Archive of Mechanical Engineering

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2017

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Vol. LXIV, nr 2

257--282

EN

The present work focuses on a first study for a piezoelectric harvesting system, finalized to the obtaining of electrical energy from the kinetic energy of rainy precipitation, a renewable energy source not really considered until now. The system, after the realization, can be collocated on the roof of an house, configuring a “Piezo Roof Harvesting System”. After presenting a state of art of the harvesting systems from environmental energy, linked to vibrations, using piezoelectric structures, and of piezoelectric harvesting systems functioning with rain, the authors propose an analysis of the fundamental features of rainy precipitations for the definition of the harvesting system. Then, four key patterns for the realization of a piezoelectric energy harvesting system are discussed and analysed, arriving to the choice of a cantilever beam scheme, in which the piezoelectric material works in 31 mode. An electro-mechanical model for the simulation of performance of the unit for the energetic conversion, composed of three blocks, is proposed. The model is used for a simulation campaign to perform the final choice of the more suitable piezoelectric unit, available on the market, which will be adopted for the realization of the “Piezo Roof Harvesting System”.

3

Modelowanie drgających układów mechatronicznych zawierających materiały piezoelektryczne

Buchacz A., Płaczek M.

Wybrane Problemy Inżynierskie

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2010

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nr 1

7-12

PL

W pracy przedstawiono modelowanie i badanie jednowymiarowych, drgających układów mechatronicznych, opisanych dyskretno - ciągłymi modelami matematycznymi, różniącymi się stopniem uproszczenia układu rzeczywistego. Analizując układ mechatroniczny, posłużono się przybliżoną metodą Galerkina, której dokładność uprzednio zweryfikowano, badając układ mechaniczny (pozbawiony przetwornika piezoelektrycznego). Rozpatrywano układ mechatroniczny w postaci drgającej giętnie belki wspornikowej z piezoelektrycznym, szerokopasmowym tłumikiem drgań.

EN

The paper presents process of modelling and investigation of one-dimension vibrating mechatronic systems described by discrete - continuous mathematical models, that differ in level of simplification of the real system. Approximate Galerkin method was used to analyse and assign dynamic flexibility of considered systems. To verify the approximate method, first, the mechanical system was being taken into consideration. The mechanical system is exactly the same - beam without piezoelectric transducer and external circuit. The considered mechatronic system was flexural vibrating cantilever beam with piezoelectric transducer bonded to the beam surface. The external shunting circuit was adjoined to the transducer in order to damp vibrations of the beam.

4

Two-Temperature Generalized Thermopiezoelasticity for One Dimensional Problems – State Space Approach

Youssef H. M., Bassiouny E.

Computational Methods in Science and Technology

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2008

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Vol. 14, nr 1

55-64

EN

The theory of two-temperature generalized thermoelasticity, based on the theory of Youssef is used to solve boundary value problems of one dimensional piezoelectric half-space with heating its boundary with different types of heating. The governing equations are solved in the Laplace transform domain by using state-space approach of the modern control theory. The general solution obtained is applied to a specific problems of a half-space subjected to three types of heating; the thermal shock type, the ramp type and the harmonic type. The inverse Laplace transforms are computed numerically using a method based on Fourier expansion techniques. The conductive temperature, the dynamical temperature, the stress and the strain distributions are shown graphically with some comparisons.

5

The annular crack in piezoelectric material

Dyka E., Rogowski B.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2005

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z. 82

53-64

EN

The problem of electroelasticity for piezoelectric materials containing an annular crack is considered. For axially symmetric states three potentials are utilized, which determine the displacements, the electric potential, the stresses, the components of the electric field vector and the electric displacements in piezoelectric body. Two cases of boundary-value problems are considered, namely the electrically permeable and impermeable crack boundary conditions. The three-part mixed boundary conditions are reduced into an equivalent system of simultaneous algebraic equations. By means of the coefficients, which are obtained from this system, the electrical and mechanical fields in the plane where the annular crack appears are obtained. The main results are the intensity factors for stress and electric displacement.

6

Zastosowanie elementów inteligentnych w zawieszeniach nadrezonansowych maszyn wibracyjnych

Giergiel M., Sapińska-Wcislo N.

Przegląd Mechaniczny

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2004

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nr 6

38-41

7

Nonlocal theoretical analysis of the dynamic behavior of two Griffith cracks in a piezoelectric strip

Sun Y. G., Zhou Z. G.

Archives of Mechanics

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2004

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Vol. 56, nr 4

271-291

EN

The dynamic behavior of two Griffith cracks in a strip made of piezoelectric materials under anti-plane shear waves is investigated by means of the non-local theory for impermeable crack surface conditions. A one-dimensional non-local kernel is used instead of a two-dimensional one for the anti-plane dynamic problem to obtain the stress and the electric displacement near the crack tips. By utilizing the Fourier transform, the problem can be solved by means of two pairs of triple integral equations. These equations are solved using the Schmidt method. Contrary to the classical solution, it is found that no stress and electric displacement singularity are present at the crack tip. This is shown to be consistent with the physical nature.