Vishal S. Chauhan

Pyroelectric materials for solar energy harvesting: a comparative study

Pyroelectric solar energy harvesting has been a prominent area of research for the past few years. This study is an attempt to compare different pyroelectric materials for harvesting solar energy. Seven different pyroelectric materials including (NH2CH2COOH)3H2SO4 (TGS), Sr0.5Ba0.5Nb2O6 (SBN), Ca0.2(Sr0.5Ba0.5)0.8Nb2O6 (CSBN), Pb(Zr0.5Ti0.5)O3 (PZT), polyvinylidene difluoride (PVDF), BaTiO3 and LiTaO3 were studied and compared using finite-element analysis. SBN was found to be the potential pyroelectric material with the maximum storage voltage of 11.47 V across an optimized load capacitance. SBN was subjected to further analysis, revealing an optimum power output of 4.9 μW at the optimized cycle frequency (0.040 Hz), a load resistance of 50 MΩ and a load capacitance of 4.7 μF, while the stored energy was found to be 576.87 μJ.

Finite element analysis of vibration energy harvesting using lead-free piezoelectric materials: A comparative study

Abstract In this article, the performance of various piezoelectric materials is simulated for the unimorph cantilever-type piezoelectric energy harvester. The finite element method (FEM) is used to model the piezolaminated unimorph cantilever structure. The first-order shear deformation theory (FSDT) and linear piezoelectric theory are implemented in finite element simulations. The genetic algorithm (GA) optimization approach is carried out to optimize the structural parameters of mechanical energy-based energy harvester for maximum power density and power output. The numerical simulation demonstrates the performance of lead-free piezoelectric materials in unimorph cantilever-based energy harvester. The lead-free piezoelectric material K0.5Na0.5NbO3-LiSbO3-CaTiO3 (2 wt.%) has demonstrated maximum mean power and maximum mean power density for piezoelectric energy harvester in the ambient frequency range of 90–110 Hz. Overall, the lead-free piezoelectric materials of K0.5Na0.5NbO3-LiSbO3 (KNN-LS) family have shown better performance than the conventional lead-based piezoelectric material lead zirconate titanate (PZT) in the context of piezoelectric energy harvesting devices.

Lead-free piezoelectric materials' performance in structural active vibration control

In this article, lead-free piezoelectric ceramics are investigated for active vibration control of piezolaminated composite shell structure. The shell structure is in the form of layered composite shell. Finite element modeling is performed to obtain vibratory response of the piezolaminated shell structure. Modeling is based on first-order shear deformation theory and linear piezoelectric theory. Fuzzy logic controller is used as controlling technique to reduce the vibration amplitude of vibrating shell using piezoelectric ceramics (both lead-based and lead-free). The simulation results reveal that Pb0.83La0.17(Zr0.3Ti0.7)0.9575O3 (lead zirconate titanate sensor) and (K0.475Na0.475Li0.05)(Nb0.92Ta0.05Sb0.03)O3 (KNLNTS actuator) combination reduces the vibration amplitude of vibrating shell structure faster than lead zirconate titanate (sensor) and lead zirconate titanate (actuator) combination. Moreover, for complete replacement of lead-based piezoelectric ceramics, 0.885(Bi0.5Na0.5)TiO3–0.05(Bi0.5K0.5)TiO3–0.015(Bi0.5Li0.5)TiO3–0.05BaTiO3 (BNKLBT sensor) and KNLNTS (actuator) combination is a potential candidate for active vibration control application.

Electrical Energy Generation from Hot/Cold Air Using Pyroelectric Ceramics

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.

Electromagnetic radiation during plastic deformation under unrestricted quasi-static compression in metals and alloys

Abstract Intermittent electromagnetic radiation (EMR) emissions from metals and alloys during deformation under unrestricted quasi-static compression are reported in this paper. The end surface conditions of the compressing platens, whether lubricated or unlubricated, influence the EMR emission characteristics. The EMR emissions under compression show shape anisotropy. The first EMR emission invariably occurs near the yield. The EMR emission characteristics are also influenced by the crystal structure. During axial compression, dead metal zones formed on the top and bottom portions of the specimens possibly generate a climbing motion of edge dislocations in the radially outward mid-regions. During the climbing motion, these edge dislocations form accelerated electric line dipoles and emit electromagnetic radiation. These EMR emissions can be used to evaluate the degree of damage in metallic components under compression.

Finite element analysis on active vibration control using lead zirconate titanate–Pt–based functionally graded piezoelectric material

The numerical simulations for active vibration control of the host structure using lead zirconate titanate–Pt-based functionally graded piezoelectric material are presented in this article. The material properties (both mechanical and electrical) of the lead zirconate titanate–Pt-based functionally graded piezoelectric material are graded in the thickness direction according to the volume fraction power law distribution. The finite element modeling using first-order shear deformation theory is implemented to predict static and dynamic responses of the vibrating structure. A constant negative velocity feedback controller is designed to provide closed-loop feedback control. Both static and dynamic controls of the host structure are numerically simulated to demonstrate the effectiveness of the proposed lead zirconate titanate–Pt-based functionally graded piezoelectric material. The numerical results show significant variation in sensing and actuating capability up to a certain volume fraction index (n).

Fuzzy Logic Based Active Vibration Controller

This paper presents fuzzy logic approach for active vibration control of composite shell structure using collocated piezoelectric sensor/actuator. The vibratory response of piezolaminated composite shell is modeled using degenerated finite shell element. Modeling is based upon first order shear deformation theory and linear piezoelectric theory. The fuzzy IF-THEN rules are established on analysis of the motion traits of laminated composite shell. The fuzzy logic controller (FLC) is designed using the sensor voltage and its derivative as inputs and actuator voltage as output. The simulation results illustrate that this controller has more superiority than the conventional controller.

An experimental study on thermal energy harvesting using Ca0.15(Sr0.5Ba0.5)0.85Nb2O5 pyroelectric ceramics

Abstract 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.

Assessment of grain size and lattice parameters of titanium alloy through electromagnetic emission technique

Effects of variation in grain size and lattice parameters at elevated temperatures on the electromagnetic radiation (EMR) during failure under tension of ASTM B265 Grade 2 titanium have been investigated. The EMR is observed to be anisotropic in nature. The EMR amplitude decreases with increase in grain size. The magnitude of variation depends upon the processing history of specimens. The EMR amplitude decreases exponentially with lattice parameters in titanium while the decrease in EMR frequency is polynomial in nature. The experimental results are in close agreement with the theoretical predications presented in this paper. A comparison with the results reported earlier shows that the nature of EMR responses with lattice parameters is independent of metal crystal structure. These investigations lead to a new technique for the assessment of grain size and lattice parameters in metals.

Deformation induced electromagnetic response of soft and hard PZT under impact loading

ABSTRACT 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 the PZT which give rise to electromagnetic radiation. The peak EMR voltage and the average EMR energy release rate show a linearly increasing pattern with the height of impact suggesting that these parameters could be used for monitoring excessive deformation from the structures. EMR peak voltage and average EMR energy release rate obtained from the soft PZT SP-5A are 43.42% and 53.12% higher respectively from those obtained from the hard PZT SP-4 owing to the higher resistance offered by the hard PZT to the domain switching.