A Piezothermoelastic Thin Shell Theory Applied to Active Structures

1994 ◽  
Vol 116 (3) ◽  
pp. 295-302 ◽  
Author(s):  
H. S. Tzou ◽  
R. V. Howard
Keyword(s):  
High Performance ◽  
Shell Theory ◽  
Piezoelectric Materials ◽  
Electromechanical Properties ◽  
Mechanical Loads ◽  
Active Structures ◽  
Control Electronics ◽  
Principal Directions ◽  
And Control ◽  
Thin Shell Theory

“Smart” structures with integrated sensors, actuators, and control electronics are of importance to the next-generation high-performance structural systems. Piezoelectric materials possess unique electromechanical properties, the direct and converse effects, which, respectively, can be used in sensor and actuator applications. In this study, piezothermoelastic characteristics of piezoelectric shell continua are studied and applications of the theory to active structures in sensing and control are discussed. A generic piezothermoelastic shell theory for thin piezoelectric shells is derived, using the linear piezoelectric theory and Kirchhoff-Love assumptions. It shows that the piezothermoelastic equations, in three principal directions, include thermal induced loads, as well as conventional electric and mechanical loads. The electric membrane forces and moments induced by the converse effect can be used to control the thermal and mechanical loads. A simplification procedure, based on the Lame´ parameters and radii of curvatures, is proposed and applications of the theory to (1) a piezoelectric cylindrical shell, (2) a piezoelectric ring, and (3) a piezoelectric beam are demonstrated.

scholarly journals Thermoelastic and Pyroelectric Couplings Effects on Dynamics and Active Control of Smart Piezolaminated Beam Modeled by Finite Element Method

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. Sanbi ◽  
R. Saadani ◽  
K. Sbai ◽  
M. Rahmoune
Keyword(s):  
Optimal Control ◽  
Finite Element ◽  
High Performance ◽  
Structural Systems ◽  
Control Procedure ◽  
Finite Element Approximations ◽  
Active Structures ◽  
Piezoelectric Beam ◽  
Control Electronics ◽  
And Control

Smart structures with integrated sensors, actuators, and control electronics are of importance to the next generation high-performance structural systems. In this study, thermopiezoelastic characteristics of piezoelectric beam continua are studied and applications of the theory to active structures in sensing and optimal control are discussed. Using linear thermopiezoelastic theory and Timoshenko assumptions, a generic thermopiezoelastic theory for piezolaminated composite beam is derived. Finite element equations for the thermopiezoelastic media are obtained by using the linear constitutive equations in Hamilton's principle together with the finite element approximations. The structure consists of a modeling of cantilevered piezolaminated Timoshenko beam with integrated thermopiezoelectric elements between two aluminium layers. The structure is modelled analytically and then numerically and the results of simulations are presented in order to visualize the states of their dynamics and the state of control. The optimal control LQG accompanied by the Kalman filter is applied. The effects of thermoelastic and pyroelectric couplings on the dynamics of the structure and on the control procedure are studied and discussed. We show that the control procedure cannot be perturbed by applying a thermal gradient and the control can be applied at any time during the period of vibration of the beam.

Elastic-Plastic Analysis of Pressurized Cylindrical Shells

1987 ◽  
Vol 54 (3) ◽  
pp. 597-603 ◽  
Author(s):  
G. N. Brooks
Keyword(s):  
Shell Theory ◽  
Plastic Region ◽  
Yield Condition ◽  
Elastic Plastic ◽  
Tresca Yield Condition ◽  
Axisymmetric Shell ◽  
Bending Stresses ◽  
Principal Directions ◽  
The Moment ◽  
Thin Shell Theory

Plasticity in shells is often contained near the ends of a segment where the bending stresses are significant. Outside of this local neighborhood the behavior is elastic. Thus, an axisymmetric shell can be divided along its axis into a purely elastic region away from an end and the local region where plasticity is present. The moment-curvature relation in the elastic-plastic region is calculated using the Tresca yield condition. Use of the Tresca yield condition greatly simplifies this derivation because the principal directions are known. This moment-curvature relationship is “exact” in the sense that only the standard assumptions of thin shell theory are made. The solutions of the elastic and plastic regions are matched at their intersection for an efficient numerical solution. The technique is used here to study the semi-infinite clamped cylindrical shell with an internal pressure loading.

Local electromechanical properties of ferroelectric materials for piezoelectric applications

2004 ◽  
Vol 838 ◽  
Author(s):  
A. L. Kholkin ◽  
I. K. Bdikin ◽  
V. V. Shvartsman ◽  
A. Orlova ◽  
D. Kiselev ◽  
...  
Keyword(s):  
Domain Wall ◽  
Microelectromechanical Systems ◽  
Ferroelectric Materials ◽  
Electromechanical Properties ◽  
Force Microscopy ◽  
Control Electronics ◽  
Piezoelectric Force Microscopy ◽  
And Control ◽  
Electromechanical Characterization

ABSTRACTLocal electromechanical characterization is becoming prerequisite for the development of ferroelectric-based piezoelectric devices including multilayer actuators, micromotors, piezoelectric filters and, especially, microelectromechanical systems (MEMS), which combine piezoelectric elements and control electronics on the same chip. In this work, we present the results of local electromechanical characterization of several important ferroelectric materials including Pb(Zr, Ti)O3 (PZT) and (Pb, La)(Zr, Ti)O3 (PLZT) in both thin film and ceramic form. Local piezoelectric hysteresis measurements are performed by the piezoelectric force microscopy (PFM) that detects small electric field-induced deformation on the nanoscale e. g., within the single grain of a polycrystalline material. A number of novel phenomena is observed with increasing dc bias voltage including the jump of ferroelectric domain wall to the grain boundary, the “fingerlike” instability of domain wall, and the local phase transition into ferroelectric phase.

Constitutive Modeling of Controllable Electrostrictive Structronic Thin Shells

2002 ◽  
Author(s):  
H. S. Tzou ◽  
W. K. Chai
Keyword(s):  
Smart Materials ◽  
Thin Shell ◽  
Shell Theory ◽  
Piezoelectric Materials ◽  
Thin Shells ◽  
Free Energy Function ◽  
Double Curvature ◽  
Coupling Equations ◽  
System Equations ◽  
Thin Shell Theory

Electrostrictive material is one of the key smart materials, with tremendous potentials in many engineering applications, e.g., sonar, actuators, artificial muscles, etc. The (direct) electrostrictive effect of electrostrictive materials is a quadratic dependence of stress or strain on applied electric field and this nonlinear electromechanical effect contributes significant actuation performance as compared with that of conventional piezoelectric materials. A generic electrostrictive thin shell theory and its dynamic electro-mechanical system equations are derived based on a generic double-curvature thin shell defined in the paraelectric phase. Generic mathematical models and permissible boundary conditions of electrostrictive thin shells are defined based on Hamilton’s principle, elasticity theory, Kirchhoff-Love thin shell theory and Gibbs elastic free energy function. Electro-mechanical behaviors and dynamic characteristics of electrostrictive shells are evaluated. Simplifications of the generic electrostrictive shell theory to other common geometries are demonstrated, electrostrictive/dynamic coupling equations derived, and their electromechanical characteristics discussed.

Investigation on Electrothermoelastic Behavior of FGPM Cylindrical Shells

2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Hong-Liang Dai ◽  
Yi-Nan Qi ◽  
Wei-Feng Luo
Keyword(s):  
Cylindrical Shell ◽  
Analytical Solution ◽  
Shell Theory ◽  
Thermal Environment ◽  
Piezoelectric Materials ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Sensory Structures ◽  
Functionally Graded Piezoelectric ◽  
Thin Shell Theory

AbstractThis paper presents an analytical solution for electrothermoelastic behavior of FGPM (functionally graded piezoelectric material) cylindrical shell. The cylindrical shell is assumed to be made up of two piezoelectric materials with their volume fractures varying along the thickness according to a simple power law. Based on classical thin shell theory, an analytical solution for electrothermoelastic performance of the FGPM cylindrical shell is presented. To investigate the influence of the power lower exponent, thermal environment, mechanical loading and electric boundary conditions on the electrothermoelastic behavior of FGPM cylindrical shells, numerical examples are presented and discussed, and some meaningful and valuable results are discovered, which will be very helpful for the design and application of such smart sensory structures.

scholarly journals Reduction of Polycyclic Aromatic Hydrocarbons (PAHs) in Sesame Oil Using Cellulosic Aerogel

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 644
Author(s):  
Do-Yeong Kim ◽  
Boram Kim ◽  
Han-Seung Shin
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
High Performance ◽  
Oil Quality ◽  
Acid Value ◽  
Quality Parameters ◽  
Sesame Oil ◽  
Miscanthus Sinensis ◽  
Polycyclic Aromatic ◽  
And Control

The effect of cellulosic aerogel treatments used for adsorption of four polycyclic aromatic hydrocarbons (PAHs)—benzo[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene [BaP])—generated during the manufacture of sesame oil was evaluated. In this study, eulalia (Miscanthus sinensis var. purpurascens)-based cellulosic aerogel (adsorbent) was prepared and used high performance liquid chromatography with fluorescence detection for determination of PAHs in sesame oil. In addition, changes in the sesame oil quality parameters (acid value, peroxide value, color, and fatty acid composition) following cellulosic aerogel treatment were also evaluated. The four PAHs and their total levels decreased in sesame oil samples roasted under different conditions (p < 0.05) following treatment with cellulosic aerogel. In particular, highly carcinogenic BaP was not detected after treatment with cellulosic aerogel. Moreover, there were no noticeable quality changes in the quality parameters between treated and control samples. It was concluded that eulalia-based cellulosic aerogel proved suitable for the reduction of PAHs from sesame oil and can be used as an eco-friendly adsorbent.

Advanced high-performance processing tools for diagnostics and control in fusion devices

2021 ◽  
Vol 170 ◽  
pp. 112529
Author(s):  
N. Cruz ◽  
A.J.N. Batista ◽  
J.M. Cardoso ◽  
B.B. Carvalho ◽  
P.F. Carvalho ◽  
...  
Keyword(s):  
High Performance ◽  
Diagnostics And Control ◽  
And Control

scholarly journals Detection of Antimicrobial Residues in Poultry Litter: Monitoring a Risk through a Selective and Sensitive HPLC–MS/MS Method

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1399
Author(s):  
Karina Yévenes ◽  
Ekaterina Pokrant ◽  
Lina Trincado ◽  
Lisette Lapierre ◽  
Nicolás Galarce ◽  
...  
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Poultry Litter ◽  
Chromatography Tandem Mass Spectrometry ◽  
Antimicrobial Residues ◽  
Field Samples ◽  
Liquid Chromatography Tandem Mass ◽  
Commercial Poultry ◽  
Agriculture Fertilizer ◽  
And Control

Tetracyclines, sulphonamides, and quinolones are families of antimicrobials (AMs) widely used in the poultry industry and can excrete up to 90% of AMs administrated, which accumulate in poultry litter. Worryingly, poultry litter is widely used as an agriculture fertilizer, contributing to the spread AMs residues in the environment. The aim of this research was to develop a method that could simultaneously identify and quantify three AMs families in poultry litter by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Samples of AMs free poultry litter were used to validate the method according to 657/2002/EC and VICH GL49. Results indicate that limit of detection (LOD) ranged from 8.95 to 20.86 μg kg−1, while limits of quantitation (LOQ) values were between 26.85 and 62.58 µg kg−1 of tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, enrofloxacin, ciprofloxacin, flumequine, sulfachloropyridazine, and sulfadiazine. Recoveries obtained ranged from 93 to 108%. The analysis of field samples obtained from seven commercial poultry flocks confirmed the adequacy of the method since it detected means concentrations ranging from 20 to 10,364 μg kg−1. This provides us an accurate and reliable tool to monitor AMs residues in poultry litter and control its use as agricultural fertilizer.

scholarly journals A Novel Fast-Locking ADPLL Based on Bisection Method

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1382
Author(s):  
Xiaoying Deng ◽  
Huazhang Li ◽  
Mingcheng Zhu
Keyword(s):  
High Performance ◽  
Tuning Range ◽  
Frequency Control ◽  
Control Word ◽  
Cmos Process ◽  
Bisection Method ◽  
Reference Frequency ◽  
Wide Tuning Range ◽  
Cascade Structure ◽  
And Control

Based on the idea of bisection method, a new structure of All-Digital Phased-Locked Loop (ADPLL) with fast-locking is proposed. The structure and locking method are different from the traditional ADPLLs. The Control Circuit consists of frequency compare module, mode-adjust module and control module, which is responsible for adjusting the frequency control word of digital-controlled-oscillator (DCO) by Bisection method according to the result of the frequency compare between reference clock and restructure clock. With a high frequency cascade structure, the DCO achieves wide tuning range and high resolution. The proposed ADPLL was designed in SMIC 180 nm CMOS process. The measured results show a lock range of 640-to-1920 MHz with a 40 MHz reference frequency. The ADPLL core occupies 0.04 mm2, and the power consumption is 29.48 mW, with a 1.8 V supply. The longest locking time is 23 reference cycles, 575 ns, at 1.92 GHz. When the ADPLL operates at 1.28 GHz–1.6 GHz, the locking time is the shortest, only 9 reference cycles, 225 ns. Compared with the recent high-performance ADPLLs, our design shows advantages of small area, short locking time, and wide tuning range.

scholarly journals Particle Size Effect of Lanthanum-Modified Bismuth Titanate Ceramics on Ferroelectric Effect for Energy Harvesting

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Sangmo Kim ◽  
Thi My Huyen Nguyen ◽  
Rui He ◽  
Chung Wung Bark
Keyword(s):  
Particle Size ◽  
Energy Harvesting ◽  
High Speed ◽  
High Performance ◽  
Bismuth Titanate ◽  
Vinylidene Fluoride ◽  
Piezoelectric Materials ◽  
Renewable Energy Sources ◽  
Particle Size Effect ◽  
Ferroelectric Materials

AbstractPiezoelectric nanogenerators (PNGs) have been studied as renewable energy sources. PNGs consisting of organic piezoelectric materials such as poly(vinylidene fluoride) (PVDF) containing oxide complex powder have attracted much attention for their stretchable and high-performance energy conversion. In this study, we prepared a PNG combined with PVDF and lanthanum-modified bismuth titanate (Bi4−XLaXTi3O12, BLT) ceramics as representative ferroelectric materials. The inserted BLT powder was treated by high-speed ball milling and its particle size reduced to the nanoscale. We also investigated the effect of particle size on the energy-harvesting performance of PNG without polling. As a result, nano-sized powder has a much larger surface area than micro-sized powder and is uniformly distributed inside the PNG. Moreover, nano-sized powder-mixed PNG generated higher power energy (> 4 times) than the PNG inserted micro-sized powder.

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