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Coalesce of photovoltaic effect with converse piezoelectric effect will turn into a photostrictive phenomenon. The current study conceptualizes a 1-3 photostrictive composite consists of a photovoltaic polymer as matrix and fibers of piezoelectric material. The proposed artificial photostrictive composite is capable of replacing lead-based naturally occurring photostrictive material, not only opening a potential for new applications but also caters to tailor the desired properties. Present study employs poly{4,8-bis[5-(2-ethyl-hexyl)thiophen-2-yl]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno[3,4-b] thiophene-4,6-diyl} (PTB7-Th) as organic photovoltaic polymer and Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-35PT) as the fibers. A representative volume element technique (RVE) is employed to embrace the local variation of multi-physics properties. The actuation response of cantilever and simply supported beam bonded to photostrictive composite patch is accurately predicted by finite element method, while discretizing the structure with degenerated shell element. Photostrictive composite with 60% volume fraction of fibers, arranged in square pattern have deflected the cantilever tip to 1.95 mm. Therefore, we provide 1-3 photostrictive composite as a solution for future wireless and lightweight vibration control applications.

Simultaneous action of photovoltaic effect and converse piezoelectric effect will induce the photostrictive effect. In contrast to the naturally occurring photostrictive material, the present study proposes a 0-3 photostrictive composite. The current photostrictive composite comprises of poly{4,8-bis[5-(2-ethyl-hexyl) thiophen-2-yl] benzo[1,2-b:4,5-b′] dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethyl-hexyl) carbonyl] thieno[3,4-b] thiophene-4,6-diyl} (PTB7-Th) as organic photovoltaic polymer matrix and Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-35PT) as the particulates. The current study shows that the present 0-3 photostrictive composite is a suitable alternative for the most popular lead-based photostrictive material. While evaluating all the effective elastic, dielectric, piezoelectric, and pyroelectric properties of 0-3 photostrictive composite, the effect of local fluctuations was incorporated in representative volume element (RVE) using the finite element method. A finite element formulation using a degenerated shell element is derived to simulate the actuation response of the proposed 0-3 photostrictive composite. Numerical studies have been performed on cantilever and simply supported beams. The maximum tip and center deflection of cantilever beam and simply supported beam bonded with 0-3 photostrictive patch is 9.75×10−4 mm and 1.22×10−4 mm, respectively. The maximum value of the effective piezoelectric coefficient d31eff, effective thermal expansion coefficient αeff, effective Young’s modulus E1eff, and effective pyroelectric coefficient peff of proposed 0-3 photostrictive composite are −3.81×10−13 m/V, 4.59×10−4 °C−1, 1.63×109 N/m2, and 7.57×10−5 C/m2 K, respectively, obtained at 25% volume fraction of particulates. This study opens possibilities of photostrictive coupling in composites.

Photostriction is a multiphysics phenomenon comprising of both photovoltaic effect and converse piezoelectric effect. The extensively researched photostrictive material is lead lanthanum zirconate titanate, i.e., Pb0.92La0.08(Zr0.65Ti0.35)0.98O3 (PLZT) ceramic. In contrast to the traditional approaches of improving deflection response, the current study proposes a 0–3 composite model to substantially enhance the effective material properties, which in turn significantly improves the deflection response. A computational framework based on finite element analysis is employed to 0–3 photostrictive composite of PLZT as matrix and Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-35PT) as the inclusions. The representative volume element (RVE) or unit cell technique is used to incorporate the local variation of constituent properties and to calculate photostrictive properties such as effective elastic, dielectric, piezoelectric, and pyroelectric properties. An opto-electro-thermo-mechanical finite element formulation was engaged to get the actuation response of photostrictive material bonded to cantilever and simply supported beam. The maximum deflection for cantilever beam attached to photostrictive composite patch having 25% inclusions volume fraction in 0–3 composite is found to be 38% more in comparison to pure PLZT material. It is established that the opto-electro-mechanical 0–3 composite actuators possess high potential in lightweight, compact and wireless actuation applications.

The present manuscript deals with crystallization of BiOCl structure over the 2Bi2O3–B2O3(BBO) glass surface and its photocatalytic response. The crystallization of BiOCl is obtained through systematic etching of the surface of BBO glass from the solution of hydrochloric acid of three different concentrations, and these samples are depicted with name BBO HCl1, BBO HCl2, and BBO HCl3, respectively. XRD results confirm the formation of BiOCl phase. Scanning electron microscopy reveals the flower-like hierarchical structure assembled with numerous petals over BBO HCl1, BBO HCl2, and BBO HCl3 glass samples. The contact angle of water drop is measured 90° for the as-quenched BBO, and 35°, 22°, and 16° for the BBO HCl1, BBO HCl2, and BBO HCl3 glass samples, respectively. The decrease in contact angle shows increase in the hydrophilicity of the samples. In comparison to BBO glass sample the photocatalytic activities of BBO HC1, BBO HCl2, and BBO HCl3 glass samples are investigated under the exposure of UV light. Photocatalytic degradation rate of methylene blue (MB) is observed the highest for BBO HCL3 and decreases for BBO HC1, BBO HCl2, and as-quenched BBO glass, relatively. Low-cost etching method for BiOCl crystal growth over the BBO glass substrate for superior photocatalytic property suggests the suitability of these samples as well as method in the degradation of pollutants and in the production for numerous commercial applications.

Development of the deformation monitoring techniques for the infrastructures so as to avoid catastrophic failure and resulting economic/human loss has remained a key interest of scientists and engineers. Among various deformation monitoring techniques utilized and explored by groups of researchers, electromagnetic radiation detection is one of the intriguing techniques which has remained popular in researchers’ community till today. Almost every type of material is being explored and studied by researchers for the electromagnetic emissions when subjected to external loading and/or failure. Experimental and theoretical investigations are demonstrating these emissions to be a suitable candidate for the deformation monitoring, as a failure predictor and to know about the complex phenomenon of fracture. This article presents extensive literature review and a rigorous discussion on the work done in the past several decades regarding the exploration of electromagnetic emissions from a wide variety of materials and the underlying physical mechanisms. Thus, this review is an attempt to highlight main findings, proposed physical mechanisms, prospective applications, future scope and challenges of the electromagnetic emission detection technique.

A comparative study of electromagnetic radiation (EMR) detection from Soft PZT (SP 5A) and Hard (SP 4) PZT under impact at high temperatures has been presented. EMR is detected by applying impact load on the samples at temperatures varying from 288 to 514 K. With increase in temperature, thermal energy increases imparting molecular vibrations which reduce the net effective polarization and this in turn results in the low amplitude of EMR signals. EMR voltage amplitude and EMR energy release rate show an overall decreasing pattern with increase in temperature. Experiments conducted on samples poled at different d.c. poling fields exhibit strong dependence of EMR signals on d.c. poling field. EMR voltage amplitude is found to increase with increase in the strength of d.c. poling field. This study pertaining to the effect of poling as well as high temperatures on the EMR signal variation will be an aid towards the development of wireless sensing technique.

This paper presents the novel triply periodic minimal surface (TPMS) based photostrictive composite as an alternative to naturally occurring photostrictive materials. The non-thermal, light-induced mechanical strain i.e., photostriction involves the simultaneous action of photovoltaic effect and converse piezoelectric effect. All the effective elastic, dielectric, piezoelectric, and pyroelectric properties are evaluated using the finite element analysis and compared with traditional micromechanical models for fibrous composites. Degenerated shell element is used to simulate the actuation response of unimorph cantilever and simply supported beams bonded with TPMS based photostrictive composite. The proposed photostrictive composite consists of poly{4,8-bis[5-(2-ethyl-hexyl) thiophen-2-yl] benzo[1,2-b:4,5-b'] dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethyl-hexyl) carbonyl] thieno[3,4-b] thiophene-4,6-diyl} (PTB7-Th) as photovoltaic polymer matrix and Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN-35PT) as TPMS—based filler material. The proposed TPMS based photostrictive composite induces 10 times larger actuation than 0–3 photostrictive composite. Also, the maximum deflection (3.22×10−5 m) of cantilever smart beam, achieved with Schoen-I-WP based photostrictive composite, is more than that achieved with Schoen-gyroid based photostrictive composite i.e., 2.78×10−5 m. Similar trends are obtained for simply supported smart beam where the center deflection for Schoen-I-WP based photostrictive composite and Schoen-gyroid based photostrictive composite are found to be 4.04×10−6 m and 3.49×10−6 m, respectively. The proposed novel photostrictive composite has potential for future wireless actuation applications.

Effective properties of a polyethylene matrix and $$0.965\left({K}_{0.48}N{a}_{0.52}\right)\left(N{b}_{0.96}S{b}_{0.04}\right){O}_{3}-0.035B{i}_{0.5}N{a}_{0.5}Z{r}_{0.15}H{f}_{0.75}{O}_{3}$$ (KNNS-BNZH) inclusion piezocomposite were calculated using finite element method. Auxetic [negative Poisson's ratio (NPR); $$\nu =-0.32$$ ] and non-auxetic (positive Poisson’s ratio $$\nu =0.2$$ ) polyethylene matrix was considered. Sensing, actuation, and energy harvesting performance of the piezocomposite are investigated at six different volume fractions using the effective properties. Performance was found to improve with an increase in volume fractions of the KNNS-BNZH piezoelectric inclusions in the polyethylene matrix. Significant improvement in voltage and harvested power was observed in the case of longitudinal mode when auxetic polyethylene matrix was used compared to non-auxetic. Poisson’s ratios effect was studied by varying it between $$\nu =-0.9$$ and $$\nu =0.4$$ at 30% piezoelectric inclusion by volume fraction. Sensing, actuation, and energy harvesting performance were studied at each Poisson’s ratio both in transverse and longitudinal modes. Auxetic piezocomposite at $$\nu =-0.9$$ performed better compared to non-auxetic at $$\nu =0.4$$ . Voltage, actuation, and power all increased with the use of auxetic polyethylene matrix as compared to the non-auxetic one.

Only a few piezoelectric materials interact with light owing to their wide bandgap, which leaves researchers with very few options. The high piezoelectric coupling coefficient of lead lanthanum zirconate titanate, i.e., PLZT (Pb0.92La0.08(Zr0.65Ti0.35)0.98O3), makes it very popular amongst the research fraternities. In this paper, piezoelectric coupling coefficient is further improved by designing a 1–3 composite of PLZT as matrix and fibers of PMN35PT (Pb(Mg1/3Nb2/3)O3–0.35PbTiO3). First, a finite element method is applied to representative volume elements of 1–3 photostrictive composites to determine the elastic, piezoelectric, pyroelectric, and thermal expansion coefficient. Secondly, degenerated shell element-based finite element formulation is used to simulate the actuation response of host structure bonded with 1–3 photostrictive composite, while prescribed with cantilever and simply supported boundary conditions. It is observed that the 1–3 composite of PLZT and PMN-35PT has 15% higher piezoelectric coupling coefficient and its pyroelectric coefficient is 7.5 times of PLZT material. Keeping the constant geometrical and boundary conditions, the structure equipped with the proposed 1–3 photostrictive composite produces a 74.8% enhanced actuation response.

Finite element study was conducted on porous cement-based 0–3 piezocomposite materials to calculate their effective properties and predict their sensing capabilities. Piezoelectric materials used are $${\text{Li}}_{{{0}{\text{.03}}}} \left( {{\text{K}}_{{{0}{\text{.48}}}} {\text{Na}}_{{{0}{\text{.52}}}} } \right)_{{{0}{\text{.97}}}} \left( {{\text{Nb}}_{{{0}{\text{.8}}}} {\text{Ta}}_{{{0}{\text{.2}}}} } \right){\text{O}}_{{3}}$$ (KNNLT), $${\text{BaTiO}}_{{3}}$$ (BT), $${\text{Pb}}\left[ {{\text{Zr}}_{{\text{x}}} {\text{Ti}}_{{\text{1 - x}}} } \right]{\text{O}}_{{3}} { }$$ (PZT-5A) and $${\text{Pb}}\left( {{\text{Zn}}_{{1/3}} {\text{Nb}}_{{2/3}} } \right){\text{O}}_{{3}} { - }\left( {{\text{6 - 7\% }}} \right){\text{PbTiO}}_{{3}} { }\left( {\text{PZN - PT}} \right)$$ . Effective elastic and piezoelectric properties of the porous cement-based piezocomposites were calculated using representative volume element approach along with suitable boundary conditions. Pores in the cement matrix are modelled as air inclusions. The elastic and piezoelectric properties were found to increase with an increase in the volume fraction of the piezoelectric material within the cement matrix. On the other hand, these properties were found to decrease with an increase in volume fraction of pores within the cement matrix. The calculated effective properties data were used to analyse the possible use of this materials for sensing application. Maximum sensing voltage was obtained at natural frequency of vibration of the structure. $${\text{PZT - 5A}}$$ demonstrated maximum voltage of $${\text{165 V}}$$ at $$0\%$$ porosity and $$15\%$$ inclusion by volume fraction. For the remaining material, the maximum sensing voltage was found to be around $$50\%$$ of the maximum voltage obtained from $${\text{PZT - 5A}}$$ . Maximum sensing voltage increased with an increase in volume fraction of piezoelectric inclusion and decreased with an increase in volume fraction of the pores. Maximum percentage drop in voltage was observed in $${\text{PZN - PT}}$$ at all inclusion volume fraction. $${\text{PZT - 5A}}$$ demonstrated least percentage drop in voltage with porosity at different inclusions. $${\text{KNNLT}}$$ and $${\text{BaTiO}}_{{3}}$$ demonstrated about $$6.5\%$$ and $$5 \%$$ drop in voltage with porosity at $$15\%$$ piezoelectric inclusion by volume fraction. At other inclusion volume fractions, the drop in voltage was found to be negligible.

Electromagnetic radiation (EMR) signals from soft (SP 5A) and hard (SP 4) PZT ceramics under the influence of alternating electric fields have been investigated. The 180° oscillations of dipoles present in the piezoelectric ceramics give rise to EMR voltage signals. The soft PZT shows higher EMR signals as compared to the hard PZT which is due to the ease in the movement of dipoles in the soft PZT because of the existing vacancies which is its characteristic feature. On the other hand, the hard PZT having no vacancies does not allow that much free movement of dipoles under the effect of the external stimulus. The EMR signals have been measured using the non-contact detection technique in which an annular antenna made up of copper was placed around the samples to obtain the EMR signals which were measured during the application of an alternating electric field on the samples. The effect of frequency has been experimentally explored and it has been observed that the EMR signal increases with the increase in the frequency of the applied alternating electric field due to the increase in the frequency of oscillations of the dipoles. When the EMR voltage is measured with increasing distance from the sample, it shows the decaying pattern which matches the pattern with which electromagnetic radiations fall off with distance. The results from the analytical model are in agreement with the experimental results. These materials and measurement technique show their potential for wireless sensing applications using piezoelectric materials which have the potential to replace the currently used wired sensors.

This paper presents the electromagnetic radiation (EMR) response of Portland Pozzolana cement paste samples and samples with addition of fly ash under impact. A peak EMR voltage ranging from 66 to ...

Lead-free (1−x)Bi0.5(Na0.8K0.2)0.5TiO3–xBaZr0.1Ti0.9O3 (with x = 0.0, 0.02, 0.025, 0.030, 0.035, 0.040) were prepared by conventional solid state reaction method. The effect of different amount of barium zirconate titanate (BZT) on structural, microstructural, ferroelectric and piezoelectric properties was examined experimentally through X-ray diffraction, scanning electron microscope and field-induced polarization and strain measurement. The coexistence of rhombohedral/tetragonal phase has been observed in pure BNKT. Now, with the addition of BZT contents in pure BNKT, the tetragonal phase has been observed to be dominant over rhombohedral, but still, mixed phase coexists in entire composition range. The temperature dependent dielectric constant and room temperature ferroelectric hysteresis show a strong dependence on their crystallographic phases. Piezoelectric properties reveal that the BNKT–0.025BZT ceramic has a large unipolar strain of 0.21% (Smax/Emax = 430 pm/V) at room temperature under an external field of 5 kV/mm. Addition of BZT reduces the remnant polarization and hysteresis loss, suggesting ferroelectric ceramics for future energy storage applications.

Electromagnetic responses of cement–PZT composites under impact loading have been presented in this work. The values of density, dielectric constant and EMR voltage increase while that of porosity ...

We report electromagnetic radiation (EMR) detection from Soft PZT (SP-5A) under impact at low temperature (300–203 K). EMR from our sample was detected by a copper loop antenna placed around the sample. We found that EMR amplitude decreases with lowering the temperature at which the sample was placed. Low temperatures restrict the domain wall motion, due to which dipole movement becomes hindered, which hampers the movement of the charges. Reduced acceleration of charges under impact corresponds to the reduced amplitude of the EMR signals. EMR voltage decreases from 68 V to 21 V as temperature decreases from 300 K to 203 K. The average EMR energy release rate shows a smoothly declining pattern with the decrease in the sample temperature, as well as in hf/kT. EMR detection was made by elastically deforming the samples. Significant EMR voltage even at adverse operating temperatures suggests potential of these materials and this technique for structural health monitoring.

Electromagnetic radiation (EMR) responses from cement–BaTiO3 (BT) composites under impact loading have been presented in this paper. The bulk density, dielectric constant and piezoelectric charge coefficient of the cement-BT composites are observed to increase while the loss tangent decreases with increase in BT content in the composites. Measurements have been carried out using cylindrical, semi-cylindrical and quarter cylindrical antennae. Marked enhancement in the values of EMR voltage for all experiments at different heights of impact and with different antennae is observed as the content of BT is increased from 5% to 40% in the cement–BT composites. The EMR voltage increases, respectively from 0.58 V to 1.16 V, 384–732 mV and 259–520 mV for cylindrical antenna, semi-cylindrical antenna and quarter cylindrical antenna with the increase in BT content from 5% to 40% in cement–BT composites at the same level of impact (height of impact = 21 cm). Also average EMR energy release rate increases from 0.00007 V2–sec/sec to 0.00047 V2–sec/sec, 0.000065 V2 – sec/sec to 0.000214 V2 – sec/sec and 0.000032 V2 – sec/sec to 0.000135 V2 – sec/sec with the increase in BT content from 5% to 40% in cement–BT composites impacted from a height of 21 cm as measured by cylindrical antenna, semi-cylindrical antenna and quarter cylindrical antenna respectively. The EMR voltage is observed to decrease smoothly initially and then attain constancy with increase in distance of measurement location from the sample. In addition, the EMR responses were found to be proportional to the height of impact in all the cement–BT composites indicating that EMR measurement technique can effectively be used for structural health monitoring.

The present article deals with 2Bi2O3-B2O3 (BBO) glass whose photocatalytic activity has been enhanced by the method of wet etching using an aqueous solution of hydrofluoric acid (HF). X-ray diffraction of the samples reveals that etching with an aqueous solution of HF leads to the formation of BiF3 and BiO0.1F2.8 phases. Surface morphology obtained from scanning electron microscopy show granular and plate-like morphology on the etched glass samples. Rhodamine 6G (Rh 6G) has been used to investigate the photocatalytic activity of the as-quenched and etched glasses. Enhanced visible light-driven photocatalytic activity was observed in HF etched glass-ceramics compared to the as-quenched BBO glass. Contact angle of the as-quenched glass was 90.2°, which decreases up to 20.02° with an increase in concentration of HF in the etching solution. Enhanced photocatalytic activity and increase in the hydrophilic nature suggests the efficient treatment of water pollutants by using the prepared surface crystallized glass–ceramics.

This paper presents a mathematical model for electromagnetic radiation (EMR) from a ferroelectric material under applied alternating electric field. Well known ferroelectric material BaTiO3 has been chosen for the investigation. For calculations a cylindrical sample of the material was chosen and uniform oscillations of the electric dipoles on the application of electrical field have been considered. For substantiating the theoretical results, fresh experimental results on EMR signals have been obtained. Continuous EMR signal is obtained both theoretically and experimentally under the influence of alternating electric field. As expected the strength of EMR signal changes upon variation in the alternating electric field strength. The obtained theoretical and experimental values of signal were found to be close to each other. The EMR signal from the material is found to have strong dependence on the number of electric dipoles within the skin depth of the material.

In the present article, a parametric study on the geometric nonlinear static and dynamic analysis of thin functionally graded structure sandwiched between functionally graded piezoelectric materials is presented. The properties of functionally graded material are graded in the thickness direction according to a power law distribution and variation of electric field is assumed to be quadratic across the thickness of functionally graded piezoelectric materials layers. The structure is modeled using finite element modeling. The finite element formulation is derived using Hamilton’s principle using full geometric nonlinearities. This is done by using Green-Lagrangian strains instead of von-Karman strains which are usually used by most researchers while conducting similar studies. The ensued non-linear algebraic equations are then solved using the modified Newton–Raphson method. A fuzzy logic controller is used to attenuate the vibration occurring in the host structure.

Pyroelectric performance of the composites of plaster of Paris (POP) and the lead-free Sr0.5Ba0.5Nb2O6 (SBN) ceramic have been studied in this paper. SBN-POP composites with 30, 40, 50, and 60% SBN content by weight referred as SBN30, SBN40, SBN50, and SBN60 have been studied. The dielectric constants for SBN30, SBN40, SBN50, and SBN60 composites are obtained as 10.51, 21.62, 43.61, and 57, respectively at room temperature (25 °C). The maximum open-circuit voltages in the range of 31 to 103 mV could be obtained by subjecting the SBN-POP composite samples to temperature gradient by blowing hot and cold air. Further maximum voltages in the range of 8 to 34 mV and maximum current in the range of 2.9 to 18 nA could be obtained across 1 MΩ resistance. The SBN-POP composites seem to be suitable candidate to be used as pyroelectric sensors.

Perovskite type (1-x)Bi0.5(Na0.8K0.2)0.5TiO3–xBaTiO3 (x = 0.0–0.05) ceramics were prepared by conventional solid state reaction method. X-ray diffraction revealed a phase transition from rh...

Finite element analysis of 0–3 composites made of piezoceramic particles and pores embedded in polyvinylidene difluoride (PVDF) has been carried out. The representative volume element (RVE) approach was used to calculate the effective elastic and piezoelectric properties of the periodic isotropic 0–3 piezoelectric composites. It was observed that the elastic and piezoelectric properties increased with the volume fraction of $${\hbox{K}}_{0.475} {\hbox{Na}}_{0.475} {\hbox{Li}}_{0.05} \left( {{\hbox{Nb}}_{0.92} {\hbox{Ta}}_{0.05} {\hbox{Sb}}_{0.03} } \right){\hbox{O}}_{3}$$ (KNLNTS) particles but decreased for the porous composites. These effective properties were further used to analyze the potential use of such bimorph cantilever beams in sensing and energy harvesting applications. Sensing voltage continuously increased for KNLNTS filled composites while for porous materials it increased up to 15% volume fraction porosity and then decreased. The same trend was also observed for the power produced by the harvester. However, the sensing voltage and power produced by harvesters made of porous composites were lower than for harvesters made of pure PVDF.

The field of waste thermal energy harvesting has experienced significant growth over the past few years. This paper presents an experimental study on thermal radiation to electrical energy conversion using pyroelectric material (PbZrxTi1-xO3 (PZT-5H)). Pyroelectric material was exposed to UV lamp with a constant frequency of 0.5 Hz and another surface of sample was continuously cooled via natural air fan (for generation continuous temporal gradient in material). Maximum value of stored energy was 1.75 µJ across 100 µF without load resistance. Maximum power output was found to be 0.76 µW across load resistance of 3 MΩ and 10 µF.

Electromagnetic radiation (EMR) from soft and hard PZT under the drop weight impact have been studied. Due to impact the PZT undergoes a deformation wave which causes oscillations of dipoles within...

This article deals with the geometric nonlinear static and dynamic analyses of thin functionally graded structure sandwiched between functionally graded piezoelectric materials. The properties of functionally graded material are graded in thickness direction according to power law distribution, and the variation in electric potential is assumed to be quadratic across the thickness of functionally graded piezoelectric material layers. The functionally graded material structure is modeled using finite element modeling considering complete Green–Lagrangian strains. The finite element formulation is derived using Hamilton’s principle based on first-order shear deformation theory. The ensued nonlinear algebraic equations are then solved using the modified Newton–Raphson method. Shape and vibration control of functionally graded plate is presented using functionally graded piezoelectric material. Fuzzy logic controller is used to control the vibrations. The numerical results predict that functionally graded piezoelectric material can control the shape and vibration of functionally graded plate.

This study is an experimental investigation on thermal energy harvesting using pyroelectric ceramics. Hot and cold air sources were used for generating temperature gradient in PbZrxTi1−xO3 (PZT-5H) ceramics. Four different frequencies of (heating and cooling process) 0.025, 0.05, 0.1 and 0.2 Hz were investigated for optimizing power/voltage output. Maximum output voltage of 2.51 V (across 4.7 μF and 5 MΩ) was achieved at 0.05 Hz frequency with temperature variation between 100°C and 65°C. Furthermore, maximum power density of 2.35 μW/cm3 was obtained at 0.05 Hz across 4.7 μF load capacitor and 5 MΩ load resistance. In addition to this a battery of 7 mAh capacity was charged up to 1.21 V in 55 minutes using continuous heating and cooling processes with frequency of 0.4 Hz.

Flexoelectric energy conversion, due to its universality and size dependence, is a potential candidate for applications in self-sustainable micro-electromechanical systems/nano-electromechanical systems. This study presents the performance indices for assessing flexoelectricity-driven energy conversion in micro-scale piezoelectric (non-centrosymmetric) and non-piezoelectric (centrosymmetric) dielectric materials. Electromechanical coupling coefficients for geometry selection and figures of merit for material selection for the two most common modes of operations, i.e., transverse mode as in bending of beams and longitudinal mode as in the compression of non-uniform cross section structures, are derived. An interplay of flexoelectricity and piezoelectricity in different circumstances is assessed for three different materials, namely, barium titanate (BaTiO3), Er-doped BST ceramic (Ba1-xTi0.96Sn0.04O3 + x mol. % Er), and polyvinylidene difluoride (PVDF), for transverse and longitudinal modes. In the transverse mode, BaTiO3 and BST are found to dominate at a beam thickness of 5 μm, while at 100 μm, PVDF shows substantially higher magnitudes of electromechanical coupling coefficients. A similar trend for the electromechanical coupling coefficient is observed in the longitudinal mode. PVDF has a very low magnitude of figure of merit in the transverse mode as compared to the other two materials (0.65% of BST and 0.71% of BaTiO3), while in the longitudinal mode, the figure of merit of PVDF exceeds the other two materials by a large magnitude (197 times of BST and 285 times of BaTiO3).

Investigation on the electromagnetic radiation (EMR) emission from cement-mortar/lead zirconate titanate (cement-mortar/PZT) composites using a drop-weight impact technique has been undertaken to explore its possible applications in civil structures as a sensor. Unpoled soft grade PZT (SP-5A) powder, having a particle size of 1 µm is used for preparing the cement-mortar/PZT composite samples onto which the experiments were conducted in unpoled state. The EMR generation from cement-mortar/PZT composites is due to the accelerated movement of the charged particles in the pores of hydrated cement and due to oscillations of dipoles in the PZT. The values of EMR voltage, the average release rate of EMR energy, and dominant frequency are observed to increase with the rise of the PZT content and the height of impact. The deformation/strain in the composite could be sensed by measuring the EMR voltage. Also, the addition of PZT in mortar results in an increase in the compressive strength and bulk density and a decrease in the porosity of the composite. The effect of the separation of the antenna and the composite samples on the EMR voltage has also been studied. The results obtained, foreshadow the prospect of the present non-destructive technique, a better option for structural health monitoring.

Commercially significant Li2O-Al2O3-SiO2 (LAS) glass composition with P2O5 content varying between 0 – 6.8 mol% were prepared through the conventional melt-quenching route. From high-temperature dilation results, it was found that different amount of P2O5 in the LAS glass greatly influences the phase transformation (glass transition, softening and melting) characteristics. Two LAS glass systems, namely 3.1 mol% of P2O5 (P3.1) and without P2O5 (P0) were considered further towards making low expansion glass-ceramic using bulk and sintering route due to their contrary thermal behaviour. The optimum nucleation temperature for P0 and P3.1 glass system was determined to be 640 and 700 °C, respectively using the Marotta method. Effect of heat-treatment temperature on the thermal expansion behaviours of the LAS glass-ceramic is explained in detail. Negative thermal expansion (NTE) and low expansion glass-ceramics were produced from bulk and sintering route. Transparent β–quartz s.s. based ultra-low thermal expansion (0.04 ×10–6 °C–1 between –60 °C and 400 °C) glass-ceramic was produced.

In this study, the dynamic response and the active vibration control behavior of cantilever-type structure over wide temperature range (−70°C to 70°C) are investigated experimentally and numerically. A cantilever structure of titanium alloy integrated with the collocated piezoelectric ceramic (PZT-5H) was studied for effective vibration amplitude reduction. The experimental results are verified with the numerical results which show good agreement among them. For the numerical simulations, finite element formulation using first-order shear deformation theory is implemented. The nonlinear fuzzy logic controller is designed as multi-input single-output system using 49 rules and implemented both experimentally and numerically to perform active vibration control. The results show that even moderate fluctuations in the temperature under study can considerably influence the performance of the piezoelectric ceramics used as sensors and actuators resulting in degraded performance for active vibration control.

The article deals with the development of a theoretical model to predict the nature (amplitude and shape) of deformation-induced electromagnetic radiation (EMR) in metals and alloys during progressive plastic deformation. The model explicitly embraces the effect of Peierls stress and strain hardening to envisage the nature of EMR in materials with relatively large Peierls stress. The theoretical results were evaluated for 0.15 % plain carbon steel and compared with experimental results. The signals obtained from the model were found to be exponential in shape and are in good agreement with the experimental observations. The results suggest that inclusion of strain hardening parameters in the earlier model is necessary for determining deformation induced EMR in bcc metals and alloys during progressive plastic deformation.

This paper presents a theoretical model to analyze and predict the electromagnetic radiation (EMR) during the strain hardening of metals with negligible Peierls stress. The model developed is validated by comparing it with the experimental results on the ASTM B265 grade 2 titanium reported earlier. It is observed that inclusion of time-varying stress is essential to studying EMR occurring during strain hardening. The model confirms the observation that the amplitude of oscillatory EMR is generally much larger than the amplitude of exponential EMR. Further, the variation in viscous damping as a function of strain during strain hardening too has been incorporated in the model. The nature as well as amplitude of the EMR calculated by this model matches well with the earlier reported results on titanium. The model is thus suitable for studying the EMR during plastic deformation of metals and alloys with negligible Peierls stress.

Pyroelectric materials can be used for energy harvesting in integrated Micro-Electro-Mechanical-Systems (MEMS) and low power electronics devices. This paper considers the thermal energy harvesting using Ca0.15(Sr0.5Ba0.5)0.85Nb2O5 (CSBN) pyroelectric ceramics. Hot/cold air was used to generate a continuous temporal temperature profile on the material surfaces. The maximum open circuit voltage was observed as 0.26V. The maximum stored energy was 1.9 μJ in 47 μF capacitor (without load resistance). The maximum power was found to be 2.07nW across 3 MΩ and 47 μF.

This paper presents some preliminary investigation of electromagnetic radiation (EMR) emissions from (1-x)(Bi 0.5 Na 0.5 TiO 3 )–x(BaTiO 3 ) (x = 0.04, 0.05, 0.06, 0.07 & 0.08) lead-free piezoelectric ceramics. Compositions near the morphotropic phase boundary 0.94(Bi 0.5 Na 0.5 TiO 3 )–0.06(BaTiO 3 ) (BNT-6BT) are studied. The electromagnetic radiations were detected with the help of non–contacting loop antenna placed around the sample. EMR voltage detection was done simultaneously when the piezoelectric material was subjected to alternating electric field. Digital storage oscilloscope was used to measure the EMR voltage. At highest applied alternating electric field of 5.8 kV/cm EMR Signal of 17.6 V was detected for 0.95(Bi 0.5 Na 0.5 TiO 3 )–0.05(BaTiO 3 ) (BNT-5BT). Higher frequency of the electric field leads to the higher acceleration of the dipoles of the piezoelectric material and thus leads to the higher amplitude of EMR. The EMR Voltage is observed to be proportional to the polarization and this can lead to the development of new technique of measuring extent of polarization. Also the EMR phenomenon can be used to develop sensors for non-contact excessive deformation measurement.

Low grade waste thermal energy is a prominent energy source for miniature devices. Present study reports experimental observations on thermal energy harvesting using pyroelectric ceramics (PbZrxTi1-xO3 (PZT-5H)). Appropriate electrical circuit was connected to the pyroelectric material for harvesting thermal energy. Hot/cold air was used to generate the continuous temporal temperature gradient. The temporal temperature variation was maintained as 4oC/sec. In order to study the behaviour of pyroelectric material for energy harvesting, generated charge was stored in capacitor. The maximum energy density was found to be 187.23 μJ/cm3 across 10 μF. Peak value of power output was 0.26 μW across 5MΩ and 4.7 μF.

In this study, a finite-element analysis of a varying-width piezoelectric energy harvester (PEH) has been presented. A varying-width piezoelectric energy harvester (cantilever type) has variation in the width at definite intervals along its length. To harvest the energy over the wide frequency range of environmental vibrations, nonlinearity is introduced in the stiffness by mean of two neodymium magnets. The width of the proposed varying-width cantilever PEH is calculated using block pulse functions (BPFs). The objective of applying BPFs is to proximate a triangular PEH (with fixed base) into a proposed varying-width PEH with three rectangular sections along length. The use of BPFs enable the use of rectangular patches of lead zirconate titanate (PZT-5A). This leads to a reduction in cost as machining PZT at other than straight cuts results in an extensive increase in the production costs. The varying-width piezoelectric cantilever beam is subjected to harmonic base excitations by applying a vertical acceleration of 0.2 g (g=9.81 m s−2). Numerical study indicates that the bistable varying-width PEH generates at least two times the average power than that generated by a bistable uniform-width PEH for the same volume of piezoelectric material and for the same linear natural frequency. Furthermore, the bistable varying-width PEH is optimized using a genetic algorithm technique to maximize the mean power density.

Electromagnetic radiation (EMR) signals have been detected from cubical cement mortar specimens during quasi-static compression and impact loading. In case of quasi-static compression EMR voltage vary from 45 to 13 mV while for impact height of 18 cm EMR voltage was found to vary between 434 and 228 mV. Nature of variation of EMR voltage and evaporable water content with increase in number of curing days is observed to be similar. Based on the EMR signals obtained during repetitive impacts mathematical model for EMR under impact loading is presented. Ions contained in the capillary and gel pores of the cement form dipoles and vibrations of dipoles under impact has been considered as the possible source of the observed emissions. EMR signals obtained using proposed model are in good agreement with the experimental ones in terms of nature as well as in amplitude and can be used for deformation monitoring.

In this study, the dynamic response and the active vibration control behavior of large space antenna reflector is investigated numerically over wide temperature range (−70 °C to 120 °C). A space antenna reflector of composite material integrated with collocated piezoelectric ceramic PZT-5H was studied for effective vibration amplitude reduction. For the numerical simulations, finite element formulation is employed. The nonlinear fuzzy logic controller is designed as single input–single output (SISO) system using 49 If-Then rules and implemented numerically to perform active vibration control. The results are presented in time domain and frequency domain. The numerical results show that even moderate fluctuations in temperature under study can considerably influence the performance of piezoelectric ceramics used as sensors and actuators resulting in degraded performance for active vibration control. The fuzzy logic controller can effectively attenuate the structural vibrations at both high and low temperature.

Thermal energy harvesting using the pyroelectric effect is becoming a prominent area of research. In the present study, an experimental investigation was performed using PbZrxTi1-xO3 (PZT-5H) ceramics, and hot/cold oil baths were used to create a continuous temporal temperature profile. The hot and cold bath temperatures were 120 °C and 25 °C, respectively. The maximum generated voltage was 11.56 V across load capacitance of 10 μF (without load resistance) in 180 s time. The maximum power obtained was 5.81 μW for a 4.7 μF load capacitance and 5 MΩ load resistance.