Article
Engineering, Civil
Jianghuai Li
Summary: This study proposes new finite element methods for functionally graded piezoelectric shells that can accurately, efficiently, and comprehensively describe such structures. The shell element is treated as a three-dimensional continuum and its middle surface is represented with a quadrilateral spectral element. The shell geometry is described by scaling the middle surface along the thickness, while the displacements and electric potential are approximated using consistent quadratic Lagrange interpolation. The developed approach is verified by solving piezoelectric or functionally graded plate problems with reference solutions. The influence of power-law index and span-to-thickness ratio on the static and free vibration behaviors of the functionally graded structures is investigated and the optimal value of lambda for general functionally graded shells is determined.
THIN-WALLED STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
K. C. Le
Summary: An asymptotically exact first-order shear deformation theory for functionally graded elastic plates is derived using the variational-asymptotic method. An analytical solution to the problem of wave propagation in a sandwich plate is found in accordance with this refined theory. Comparison between the dispersion curves obtained by 2-D plate theory and 3-D elasticity theory reveals that the former is accurate up to the order of h(2)/l(2), where h is the plate thickness and l the wavelength.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Chemistry, Analytical
Yuhang Chen, Maomao Zhang, Yaxuan Su, Zhidong Zhou
Summary: The flexoelectric effect has a significant impact on the electro-mechanical coupling of micro-nano devices, particularly in functionally graded beams. This study investigates the mechanical and electrical properties of such beams under various electrical boundary conditions, highlighting the influences of flexoelectric effect, piezoelectric effect, and gradient distribution on their performance. The results show that nonuniform piezoelectricity and polarization direction play a leading role in induced electric potential, and flexoelectric effect dominates as beam thickness decreases.
Article
Engineering, Civil
Jinpeng Su, Yegao Qu, Kun Zhang, Qiang Zhang, Ying Tian
Summary: This paper presents a modified variational method for the dynamic analysis of functionally graded piezoelectric (FGPM) deep curved beams with porosity (FGPP beam). The proposed method is validated by comparing the results with those available in literature and by presenting numerical examples. The combined effects of porosity properties with other material properties on the dynamic characteristics are examined, which are significant for optimal design of smart structures.
THIN-WALLED STRUCTURES
(2021)
Article
Mechanics
Tran Huu Quoc, Vu Van Tham, Tran Minh Tu
Summary: This study presents a finite-element model based on the four-variable shear deformation refined theory for active vibration control of a functionally graded carbon nanotube-reinforced composite spherical panel with integrated piezoelectric layers. The model's convergence and accuracy are validated through comparison with literature data, and some new parametric studies are discussed.
Article
Acoustics
Sha Wang, Cheng Chen, Liqing Hu, Shuyu Lin
Summary: In this study, a functionally graded spherical piezoelectric transducer is proposed and a precise theoretical model is constructed using a three-port electromechanical equivalent circuit model. The model allows for easy evaluation of the entire mechanical vibration system by connecting it with other vibration systems based on boundary conditions. The validity of the model is verified and the effects of key factors on the vibration characteristics of the transducer are studied, providing valuable guidance for structural optimization design.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Acoustics
Sha Wang, Cheng Chen, Liqing Hu, Shuyu Lin
Summary: In this work, a functionally graded spherical piezoelectric transducer (FG-sPET) with an accurate theoretical model is proposed, which facilitates the evaluation of the whole mechanical vibration system. The effects of geometric dimensions and non-uniform coefficients on vibration characteristics were studied to guide the structural optimization design of functionally graded piezoelectric devices.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Materials Science, Multidisciplinary
Zhenjin Wang, Kohei Maruyama, Fumio Narita
Summary: This research focuses on developing functionally graded piezocomposites for energy-harvesting applications. The study involved the creation of BTO/P(VDF-TrFE) composites with varying particle fractions and structures, followed by polarization using corona poling. The structure, properties, and piezoelectric characteristics of the composites were investigated, and impact and vibration energy production tests were conducted. The research offers a feasible manufacturing method and guidance for constructing functionally graded piezoelectric composites for various energy-harvesting applications.
MATERIALS & DESIGN
(2022)
Article
Computer Science, Information Systems
Anuruddh Kumar, Mohamed Nainar Mohamed Ansari, Sobhy M. Ibrahim, Paramanandam Thomas, Rahul Vaish
Summary: The performance of linear energy harvesters is limited by their operating frequency bandwidth, which can be improved by introducing non-linearity through magnetic piezoelectric energy harvesters. The study utilizes the simple harmonic balance method to solve the non-linearity and calculate voltage output and power in the frequency domain. Additionally, the use of functionally graded piezoelectric materials is incorporated for their superior properties.
Article
Mechanics
Yajun Cao, Huaiwei Huang, Yifei Ding
Summary: This paper proposes an isogeometric optimization method to optimize the material distribution of piezoelectric functionally graded material (PFGM) energy harvester. By conducting numerical examples, the convergence and accuracy of the optimization results, as well as the effects of the metallic volume ratio constraint and the initial design domain on the optimized material distribution, are studied.
COMPOSITE STRUCTURES
(2021)
Article
Mathematics, Applied
J. Lu, C. Yu, W. Xu, C. Chiu
Summary: This work focuses on the free vibration characteristics of the functionally graded piezoelectric (FGPE) plate with classical and elastic constraints. An analytical model is established based on the first-order shear deformation theory (FSDT), and solved using the Ritz method. The convergence and accuracy of the model are verified, and a series of parametric investigations are conducted.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2021)
Article
Engineering, Civil
Renyun Jin, Haifeng Qiu, Liguo Weng, Bin Yu, Jie Chen, Yanghui Zhang
Summary: This study investigates the mechanical buckling behavior of saturated porous toroidal shell segments sandwiched by piezoelectric actuator layers. The governing equations for the nonlinear behavior of the sandwich toroidal shell with varying porosity parameters are derived. Closed-form solutions are obtained for shallow segments with positive/negative Gaussian curvature under different mechanical loading conditions, and the effects of important factors on the buckling behavior are analyzed.
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2023)
Article
Engineering, Multidisciplinary
Jinpeng Su, Weiping He, Kun Zhang, Qiang Zhang, Yegao Qu
Summary: This paper proposes a novel energy approach for fully coupled fluid-structure problems of functionally graded porous fluid-filled cylindrical shells under arbitrary boundary conditions. The approach successfully introduces fluid-structure interactions and demonstrates good convergence, high accuracy, superior efficiency, and flexibility. The results show the method's applicability in various situations and its advantages over other methods in terms of accuracy and efficiency.
APPLIED MATHEMATICAL MODELLING
(2022)
Article
Mathematics, Applied
Wei -Wu Jiang, Xiao-Wei Gao, Bing-Bing Xu, Jun Lv
Summary: This paper presents a novel numerical algorithm for simulating the static deflection and forced vibration of piezoelectric integrated structures. The proposed method does not require variational principle and integration, and achieves accurate results compared to analytical solution and ABAQUS.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Engineering, Civil
Xianjie Shi, Peng Zuo, Rui Zhong, Chenchen Guo, Qingshan Wang
Summary: In this article, an analytical model is proposed for vibration analysis of functionally graded conical-cylindrical coupled shell under thermal environment. The model utilizes artificial spring techniques to simulate boundary and coupling conditions, and employs a spectro-geometric method and Fourier harmonic functions to standardize displacement functions. The accuracy and stability of the model are demonstrated through comparison with existing data and finite element results.
THIN-WALLED STRUCTURES
(2022)
Article
Mechanics
K. C. Le, Y. Piao
ARCHIVE OF APPLIED MECHANICS
(2019)
Article
Engineering, Mechanical
K. C. Le, Y. Piao
INTERNATIONAL JOURNAL OF PLASTICITY
(2019)
Biographical-Item
Mechanics
Andrej Cherkaev, Khanh Chau Le
ARCHIVE OF APPLIED MECHANICS
(2019)
Article
Engineering, Multidisciplinary
K. C. Le, Y. Piao
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2019)
Article
Engineering, Multidisciplinary
K. C. Le, T. H. Le, T. M. Tran
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2020)
Article
Mechanics
K. C. Le, T. M. Tran
COMPOSITE STRUCTURES
(2020)
Article
Mechanics
K. C. Le
MECHANICS RESEARCH COMMUNICATIONS
(2020)
Article
Mechanics
F. Guenther, K. C. Le
Summary: This paper investigates the plane constrained shear problem for single crystals with one active slip system under the small strain thermodynamic dislocation theory proposed by Le. The numerical solution shows combined isotropic and kinematic work hardening, sensitivity of stress-strain curves to temperature and strain rate, Bauschinger effect, and size effect.
ARCHIVE OF APPLIED MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
K. C. Le, S. L. Dang, H. T. Luu, N. Gunkelmann
Summary: This paper presents a modified version of the thermodynamic dislocation theory, which can fit the stress-strain curves of bcc crystals niobium, tantalum, tungsten, and vanadium over a wide range of temperatures and strain rates by employing a small set of physics-based material parameters identified through large scale least squares analysis.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2021)
Article
Mechanics
Yinguang Piao, Khanh Chau Le
Summary: The thermodynamic dislocation theory incorporating dislocation impediment by grain boundaries was developed to analyze shear tests on polycrystals, successfully simulating stress-strain curves consistent with experimental data. Representative distributions of plastic slip were presented, explaining the extended transition stage during load reversal.
Article
Mechanics
K. C. Le, M. El Yaagoubi
Summary: The safe equilibrium variational principle for inhomogeneous elastic cracked bodies is formulated in this study, showing that crack remains in safe equilibrium as long as the maximum energy reduction rate of the virtually growing crack is negative. The crack starts to grow in the direction of the maximum energy reduction rate when it becomes zero, implying the criteria proposed by He and Hutchinson (1989). As an application, this criterion is used to predict the growth direction of an interface crack in a bimaterial.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Thermodynamics
Yinguang Piao, Khanh Chau Le
Summary: The thermodynamic theory of dislocation/grain boundary interaction is developed for non-uniform plastic deformations in polycrystals. A case study on the boundary conditions affecting work hardening of a bicrystal is conducted for three types of grain boundaries. The results show that different types of grain boundaries have different effects on work hardening.
CONTINUUM MECHANICS AND THERMODYNAMICS
(2022)
Article
Engineering, Multidisciplinary
K. C. Le
Summary: An asymptotically exact first-order shear deformation theory for functionally graded elastic plates is derived using the variational-asymptotic method. An analytical solution to the problem of wave propagation in a sandwich plate is found in accordance with this refined theory. Comparison between the dispersion curves obtained by 2-D plate theory and 3-D elasticity theory reveals that the former is accurate up to the order of h(2)/l(2), where h is the plate thickness and l the wavelength.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Physics, Fluids & Plasmas
K. C. Le, H. Jeong, T. M. Tran
Summary: Two improvements are proposed for the theory of transition from brittle to ductile fracture developed by Langer. The first improvement includes the temperature dependence of the shear modulus to better quantify the thermally sensitive dislocation entanglement near the crack tip. The second improvement involves identifying the parameters of the improved theory using the largescale least-squares method. The comparison between the predicted fracture toughness and experimental values for tungsten shows good agreement.
Article
Multidisciplinary Sciences
J. S. Langer, K. C. Le
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2020)
Article
Engineering, Multidisciplinary
Tohya Kanahama, Motohiro Sato
Summary: This study theoretically explains the effect of initial deflection and initial slope on self-buckling characteristics of heavy columns and proposes a formula characterizing the self-buckling problem. The results show that the greatest height is proportional to the 2/3 power of radius, and the formula can potentially predict the height of tree-like natural structures.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Aps Selvadurai, Alexander P. Suvorov
Summary: This paper examines the torsion of a solid cylinder made of a fluid-saturated porous medium with a hyperelastic porous skeleton. It analyzes the mechanics of the twisted cylinder in both short-term and long-term behaviors, using numerical solutions and the ABAQUSTM finite element code.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
S. Kanaun
Summary: This study focuses on spherical radially transverse isotropic heterogeneous inclusions in homogeneous isotropic conductive host media. The volume integral equation for the field in the medium with an isolated inclusion subjected to a constant external field is solved using Mellin-transform technique. The method allows revealing tensor structure of the solution with precision to one scalar function of radial coordinate. The study also investigates the influence of neutral inclusions and conductivity coefficients on the effective conductivity of the composite material.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Marinos Kattis, Vassilis Tsitsos, Vassilis Karatzaferis
Summary: The proposed model utilizes continuum mechanics to describe the mechanical behavior of a weakened interface between materials with microstructure, simulating the weakened interface using a surface elastic medium adhering on either side with bulk elastic continua. The model is able to investigate the effect of a weakened interface on stress concentration around inhomogeneities embedded in an unbounded matrix of Cosserat materials.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Shixiang Zhao, Yu. V. Petrov, Yuyi Zhang, G. A. Volkov, Zejian Xu, Fenglei Huang
Summary: This paper theoretically studies the thermal softening related to stress relaxation using the incubation time approach and examines the temperature-time correspondence. The developed relaxation model of plasticity (RP model) is analyzed and compared with other constitutive models and artificial neural networks. The advantages and disadvantages of different models are discussed, and the differences between the ANN model and other constitutive models are examined.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)
Article
Engineering, Multidisciplinary
Ivan I. Argatov, Federico J. Sabina
Summary: This study models a seismic metabarrier as a cluster of single-degree-of-freedom resonator units and considers the scattering effects on pulsed Rayleigh waves caused by the vertical displacements of the resonators and the normal contact forces. The variation of the amplitude reduction factor due to the model parameters variation is studied in detail.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2024)