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Porous materials have been extensively used in electronic communications, aerospace, bio-medicine and petrochemical, etc. due to their attractive attributes such as low relative density, thermal and acoustical insulation and good permeability. Ultrashort laser pulses have a series of unique advantages including high energy density, ultrashort interaction time and high accuracy, which are widely used in the fields of precision machining and microelectronic manufacture. For porous materials heated by an ultrashort laser pulse, revealing the interplay between deformation field and temperature field is crucial to guide their engineering application and optimization design. The present work devotes to investigating the transient response of a porous half-space heated by a non-Gaussian laser beam on its boundary surface based on the newly established linear thermoelastic theory with strain and thermal relaxations. The coupled governing equations are formulated and solved through the Laplace transform and its numerical inversion. The distributions of the non-dimensional temperature, displacement, stress as well as volume fraction field are obtained and illustrated graphically. In calculation, the effects of the thermal relaxation factor, the strain relaxation factor on the temperature field, volume fraction field, displacement field as well as stress field are examined and discussed in detail. [ABSTRACT FROM AUTHOR]

The present work is devoted to establishing the ultrashort pulse laser ablation generalized thermoelastic model with spatio-temporal nonlocal effect and investigating the transient responses of the process of silicon ablated by the picosecond pulse laser. The research is divided into three cases. 1) The solid silicon before the target surface melting is studied, and the transient responses of the final state of this case are taken as the initial conditions of the Case Two. 2) The liquid silicon after the target surface melting is researched, and the heat flux taken away by vaporization is considered in the boundary condition. 3) The solid silicon after the target surface melting is discussed, and the moving solid-liquid interface is regarded as the coordinate origin. The coupled governing equations containing spatial nonlocal parameter, time delay factor, and kernel function are established and solved by the Laplace transform together with its numerical inversion. The melting time and depth of target are emphatically discussed. The temperature, displacement and stress with different laser intensity, spatial nonlocal parameter, time delay factor, kernel function as well as time are obtained and illustrated graphically. [ABSTRACT FROM AUTHOR]

In order to capture the memory-dependent effect and size-dependent effect, present work aims to develop a novel thermo-viscoelastic nonlocal model in micro-scale for the first time to include the simultaneous effects of the fractional order parameter, the viscous damping coefficient, the time-delay factor and the kernel function. Then, the theory is applied to studying the dynamic response of a polymer microbeam heated by a ramp-type heating. In calculation, the influences of the fractional order parameter, the viscous damping coefficient, the time-delay factor and the kernel function on the variations of the considered variables are presented and discussed in detail. [ABSTRACT FROM AUTHOR]

Compared with the fractional order generalized themoelastic theory, the generalized thermoelastic theory based on the memory-dependent derivative has following significant advantages: First, the generalized thermoelastic theory with memory-dependent derivative has more specific physical meanings and can excellently describe that the present state of a system is dependent on its past states; Second, the memory-dependent derivative is based on the integer order calculus, which is more convenient to operate than fractional order model; Particularly, for different kernel functions, the time-dealy factor has different choice to adapt to different specific problems, which makes it greatly possible to describe the real thermoelastic response of medium. In present work, the transient response of an infinite rotating hollow cylindrical conductor with variable material properties subjected to a thermal shock at its inner surface is investigated based on the generalized thermoelastic theory with memory-dependent derivative. The hollow cylinder is placed in an external magnetic field with constant intensity, whose outer surface is traction free. The governing equations are formulated and then solved by using Laplace transform and its numerical inversion. The distributions of the dimensionless temperature, displacement, induced electric field, induced magnetic field, hoop stress as well as radial stress in the cylinder are obtained and illustrated graphically. The obtained results show that the kernel function, the time-delay factor and the temperature-dependent material properties influence the distributions of the considered variables more or less, while, the angular velocity significantly influence the variations of the dimensionless displacement, hoop stress and radial stress. [ABSTRACT FROM AUTHOR]

Nano sandwich-like storage structure or device is commonly designed as diaphragm to extend nano-battery working life, or fabricated as nanocomposite anode materials to maximumly improve electrochemical performance in nano-battery systems. This work aims to investigate size-dependent dynamic mechanical-diffusion responses of multi-layered laminated sandwich-like nanocomposites subjected to shock loadings of molar concentration in the context of nonlocal diffusion-elasticity model by a semi-analytical technique via Laplace transformation. The results reveal that the diffusion isolation will be maximally improved and lager harmful chemical stresses can be reduced to some extent for proper materials nonlocal parameters and constants ratios of selected. [ABSTRACT FROM AUTHOR]

With the extensive applications of the micro/nano-electro-mechanical systems, a great deal of attention has been paid to explore the influences of the arising size-dependent effect and surface effect on their performance. Along with these effects, the nonlocal elasticity, strain gradient theory, and surface elasticity theory were successively proposed. Moreover, it is inevitable for MEMS/NEMS to work in a variable temperature environment, correspondingly, the thermal-induced stress or deformation becomes another issue that needs serious concern. Thermoelastic damping (TED), as a main energy dissipation source, is a major challenge in designing higher-quality factor resonators. However, considering the thermoelastic coupling effect, the aforementioned theories are not capable enough to depict the thermoelastic performance of micro/nano-resonators. To amend this deficiency, based on nonlocal strain gradient theory, a new model for assessing the TED of nanobeam resonators by incorporating the thermal relaxation effect and the surface effect is developed. The corresponding governing equations for the Euler–Bernoulli microbeam resonator model are formulated, and then, solved by means of a complex frequency method. The influences of the nonlocal parameter, strain gradient coefficients, aspect ratio, surface stress and surface elasticity on the TED are examined and discussed in detail. [ABSTRACT FROM AUTHOR]

The applicability of the generalized thermoelastic theories with integer-order derivative in solving anomalous or transient thermoelastic diffusion problems is questionable. Due to the feature of memory-dependence and heredity, the fractional-order derivative and the memory-dependent derivative are introduced to modify the generalized thermoelastic theories for extending their applicability. To demonstrate the features of such theories, the thermoelastic-diffusive dynamic response of an infinite elastic medium containing a spherical cavity with variable material properties is investigated in three different generalized theories with memory-dependent effect, which are incorporated in a unified form. Of them, two are based on fractional-order derivative and the other one is based on the memory-dependent derivative. The corresponding governing equations are formulated and then solved by Laplace transform together with its numerical inversion. The distributions of the non-dimensional temperature, displacement, stress, concentration and chemical potential under the three theories are obtained and illustrated graphically for comparing with those obtained from one of the integer-order theories. The effects of the fractional-order parameter, the time-delay factor, the variable thermal conductivity and diffusivity on the variations of the considered variables are considered and discussed in detail. [ABSTRACT FROM AUTHOR]

For nano/micro-scale structures, the classical continuum mechanics can't properly depict the size-dependent effect arising in them anymore. In addition, Fourier's law is limited in describing the heat transfer process in nano/microstructures due to its nature of predicting infinite heat speed. To amend such defects, the non-classical continuum mechanics based on the nonlocal elasticity theory and the modified couple stress theory incorporating the non-Fourier heat transfer model with memory-dependent effect is formulated to characterize the thermoelastic behaviors in micro/nano-scale system in the present work. Then, the model is used to study the dynamic response of an Euler-Bernoulli nanobeam subjected to a ramp-type heating. The corresponding governing equations are derived and then solved by Laplace transform method and its numerical inversion. The distributions of the non-dimensional transverse deflection, temperature and displacement are obtained and illustrated graphically. In calculation, the influences of the ramp heating time parameter, the material length parameter, the nonlocal parameter, the time-delay factor and the kernel functions on the considered physical quantities are examined and discussed in detail. [ABSTRACT FROM AUTHOR]

Porous materials have been widely used in aerospace, electronic communication, petrochemical and bio-medicine, etc. due to their attractive attributes such as low relative density, thermal and acoustical insulation and good permeability. For porous materials suffering high temperature gradient or ultrafast heating, etc., it is crucial to reveal the behaviors of the thermal-induced stress and deformation within them for guiding their potential applications and optimizations. In present work, the thermoelastic dynamic behaviors of a porous half-space subjected to a ramp-type heating is investigated based on the theory for thermoelastic porous materials and the three-phase-lag heat conduction model. The governing equations of the problem are formulated, and then, solved by using Laplace transform and its numerical inversion. The distributions of the nondimensional temperature, displacement, stress and volume fraction within the half-space are obtained and illustrated graphically. In calculation, the effects of time, ramp-heating time factor and thermal time-delay factors on the considered physical quantities are examined and discussed in detail. Comparisons of the variations of the considered quantities under three different theories are carried out and presented. [ABSTRACT FROM AUTHOR]

With the rapid development of ultrafast heating technologies and its application in the micro-machining of micro/nano-electromechanical devices, where the nonlocal effects on elastic deformation and heat/mass transfer will increase and classical/generalized theory of thermoelastic diffusion coupling does not hold any more. In this work, a nonlocal theory of thermoelastic diffusive materials is developed, and the spatial nonlocal effects of heat and mass transport are both considered for the first time. With the aid of thermodynamic principles, the constitutive relations involving size-dependent characteristic lengths are derived. In the aspect of the application, the proposed theoretical model is further used to investigate the dynamic thermo-elasto-diffusive responses of a one-dimensional semi-infinite medium with one end subjected to time-dependent shock loads, and the semi-analytical techniques based on Laplace transform methods are applied to obtain the transient solutions. The effects of nonlocal parameters on structural dynamic thermo-elasto-diffusive responses are also evaluated and discussed to be expected to provide new insights on the thermoelastic diffusion coupling at the micro/nanoscale. [ABSTRACT FROM AUTHOR]

The present work devotes to investigating the transient responses of a half-space with variable thermal material properties based on the generalized thermoelastic theory with memory-dependent derivative. The bounding surface is assumed to be traction free and heated by a non-Gaussian laser beam. The material characteristic parameters are assumed as the linear function of temperature. The coupled governing equations containing thermal time-delay factor and kernel function, which can be chosen to adapt to specific problems, are formulated and solved by the Laplace and Kirchhoff transformations. Numerical results of the non-dimensional temperature, displacement as well as stress under different time, variable thermal conductivity, thermal time-delay factor and kernel function are obtained and illustrated graphically. It is hoped that the obtained results would be helpful in designing the temperature-dependent structures heated by a non-Gaussian laser beam in engineering. [ABSTRACT FROM AUTHOR]

Viscoelastic laminated sandwich composite structure has been used as a new class of high-efficient structural damping in the passive vibration control systems. This work aims to investigate transient thermo-viscoelastic responses of viscoelastic laminated sandwich composite structure. The effects of fractional order parameters and material constants ratio on the structural transient thermo-viscoelastic responses are evaluated and discussed. For each homogeneous isotropic layer, the governing equations are formulated and solved by Laplace transformation techniques. The results are expected to provide new insights on the vibration control and thermal management of viscoelastic laminated sandwich composite structure under extreme non-isothermal conditions. [ABSTRACT FROM AUTHOR]

Multi-cell storage devices (e.g. lithium-ion batteries (LIBs)) stand as one of the most important components which are widely used in battery energy storage technology for renewable energy power system, hybrid electric vehicles and portable electronic devices due to its high energy density and low manufacturing cost. In recent years, there has been an explosion of developing new and multifunctional nanomaterials with particular interest to electrode nanomaterials (nano-MnO2, nano-LiMn2O4, etc.). In such case, size-dependent mechanical-diffusion responses analysis of multilayered composite nanostructure under non-uniform concentration in-service environment will become significantly important. To address the problem, a multilayered composite nanoplates account for diffusion impedance and elastic wave impedance at the interface is considered in this research. Governing equations involving with size-dependent characteristic lengths and material constant ratio of each two adjacent layers are formulated, and then, a semi-analytical approach via the Laplace transformation is applied. Then, the obtained solutions are applied to bilayered composite nanoplates, and the influences of size effects and material constants ratio on structural responses are emphatically discussed to provide guidelines on and new insights into the optimal design and management of mechanical responses and vibration control of nano-sized multi-cell storage devices under non-uniform concentration environment, especially for the nano-coating. [ABSTRACT FROM AUTHOR]

With the great development of micro-electromechanical devices and wide application of subpicosecond/femtosecond ultrafast laser technology in micro-machining of micro-electromechanical devices, the investigations of interactions between thermodiffusion and deformation become significantly important. To accurate modeling the thermo-elasto-diffusive coupling, a new time fractional-order (i.e. memory-dependent derivative) based model of generalized thermoelastic diffusion for a perfect thermally and isotropic conducting medium which is assumed to have variable thermal conductivity and diffusivity is given in this work. This model is applied to investigate transient responses of a spherical shell subjected to instantaneous thermal and chemical shock loadings at external surface, whilst it is assumed that a permeating substance is in contact with the rigid surface at its internal surface. The solutions in the Laplace transform domain are obtained by using Kirchhoff and Laplace transform techniques and then the numerical inversion process based on fast Fourier transformation is carried out to derive the transient solutions in the time domain. Numerical computations for all the physical quantities considered are implemented and represented graphically. The results show that the variable thermal conductivity and diffusivity as well as memory-dependent parameters have the varying degrees of influences on the structural transient thermo-elasto-diffusive responses. [ABSTRACT FROM AUTHOR]

Based on the generalized thermoelasticity with memory-dependent derivative, the transient response of a half-space heated by a non-Gaussian laser beam on its boundary is investigated. The coupled governing equations containing thermal time-delay factor and thermal kernel function, which can be chosen to adapt to specific problems, are formulated and solved by the Laplace transform technique and its numerical inversion. For the functionally graded half-space, its material properties are assumed to exponentially vary with material coordinate. In calculation, the non-dimensional temperature, displacement as well as stress under different thermal time-delay factor, thermal kernel function and functionally graded parameter are obtained and illustrated graphically. The results show that: with the decrease of thermal time-delay factor or the increase of exponent n of thermal kernel function, the peak value of the non-dimensional temperature, displacement and the absolute value of peak value of stress increase; negative temperature value, positive displacement and stress values will appear when functionally graded parameter is less than zero. It is hoped that the obtained results would be helpful in designing the functionally graded materials heated by a non-Gaussian laser beam in engineering. [ABSTRACT FROM AUTHOR]

Viscoelastic nanomaterials (e.g., ethylene glycol-Al2O3, ethylene glycol-ZnO, etc.) have become one of the most promising candidates for nanodevices/nanocomposites, which are widely used as high-efficient nano colloidal dampers, nano-sensors, and nano-actuators in nanoengineering due to their excellent mechanical, thermal, and chemical properties. Present study aims to develop a complete size-dependent thermo-viscoelastic coupling model accounting for two fundamentally distinct size-dependent models which govern the nonlocal feature of heat transport and viscoelastic deformation, respectively. The proposed model is applied to investigate the transient responses of a bi-layered composite viscoelastic nanoplate with nonidealized interfacial conditions of thermal contact resistance and elastic wave impedance. [ABSTRACT FROM AUTHOR]

The instantaneous change of concentration in the rapid charging of Li-ions batteries can result in the Li-ions diffusion and diffusion-induced stresses. In such situation, the accurate description of the interaction mechanism between mass diffusion with matter is of great importance for the fabrication and exploitation of nano-electrochemical devices under non-uniform concentration in-service environment. To deal with such problems, this paper aims to establish a size-dependent diffusion-elasticity model is with the consideration of spatial nonlocal effects of concentration and strain fields. The proposed model is then applied to investigate the dynamic responses of a thick nanoplate under transient concentration loads. [ABSTRACT FROM AUTHOR]

Due to the advantages of high-power density, short duration, and high machining accuracy, ultrashort laser pulses are widely used in the fields of ultra-precision machining and microelectronic manufacture. In the manuscript, the L-S generalized thermoelastic diffusion theory considering the memory-dependent effect and spatial nonlocal effect is established and the thermoelastic diffusion responses of a semi-infinite thin plate subjected to a non-Gaussian laser pulse and a chemical shock on its boundary are studied. The Laplace integral transformation and its numerical inversion are used to solve the problem. The variation of the temperature, chemical potential, displacement, stress, and concentration with different nonlocal parameters, time delay factors, and kernel functions are obtained. The results show that heat conduction has a significant effect on mass transfer, while mass transfer has little effect on heat conduction; nonlocal parameter has a significant influence on displacement and stress, but little effect on temperature, chemical potential, and concentration. The establishment of this theory and the solution of the corresponding problem are aimed at reasonably predicting the transient responses of heat conduction and mass transfer under the coupling effects of mechanics, heat, and diffusion. [ABSTRACT FROM AUTHOR]

Nowadays, a multilayered viscoelastic composite structure stands as one of the most representative active/passive vibration isolator and high-efficient damper to avoid unwanted vibrations in civil and ocean engineering, which is commonly applied in harsh non-uniform temperature environment (e.g., high heat-flux, drastic changes of temperature, etc.). In such a case, thermoviscoelastic response analysis is of great importance for the safety design of viscoelastic composites, and so a thorough and comprehensive study on this issue is imperatively needed. This work aims to conduct an analytical study of transient thermomechanical responses of multilayered viscoelastic composite structure under time-dependent heating loads. In the context of generalized thermoviscoelasticity theory with time-fractional order strain, a composite laminated viscoelastic plate is chosen as the analytical model while governing equations of each homogeneous layer accounting for non-idealized interfacial conditions are systematically formulated. Then, a semi-analytical approach via Laplace transform is adopted to deal with the problem. The effects of fractional order parameters and material constants' ratio on the structural dynamic responses are fully discussed to provide new insights and basic guidelines for vibration control and thermal management of viscoelastic composites, especially for the surface coating at the interface between any two adjacent viscoelastic layers. [ABSTRACT FROM AUTHOR]

In the generalized thermoelasticity with nonlocal effect and memory-dependent derivative, the dynamic response of a finite thermoelastic rod fixed at both ends and subjected to a moving heat source is investigated. The corresponding governing equations are formulated and solved by means of Laplace transform and its numerical inversion. In simulation, the effects of the time-delay factor, the kernel function and the nonlocal parameter on the distributions of the non-dimensional temperature, displacement and stress are examined, respectively, and illustrated graphically. The results show that: the time-delay factor and the kernel function significantly affect the peak values of the considered variables; the nonlocal parameter barely influences the distributions of the non-dimensional temperature, slightly influences the peak values of the non-dimensional displacement, while remarkably influences the peak values of the non-dimensional stress. [ABSTRACT FROM AUTHOR]

Based on the generalized thermoelastic diffusion theory with fractional order derivative, the dynamic response of an infinite thermoelastic medium with a spherical cavity is investigated. The thermoelastic and diffusive properties of the medium are assumed to be temperature-dependent, and the medium is subjected to a thermal shock and a chemical potential shock at the inner surface of the spherical cavity simultaneously. The governing equations of the problem are formulated and then solved by Laplace transform together with its numerical inversion. The distributions of the non-dimensional temperature, displacement, radial stress, concentration and chemical potential are obtained and illustrated graphically. In calculation, the effects of the fractional order parameter and the temperature-dependent properties on the variations of the considered variables are presented and discussed in detail. The results show that the fractional order parameter and the temperature-dependent properties significantly influence the variations of all the considered variables. The present investigation may be valuable in heat and mass transfer, waste disposal or petroleum engineering, etc. [ABSTRACT FROM AUTHOR]

In this work, we shall formulate the fibre-reinforced two-dimensional problem of thermoelasticity for an infinite space weakened by a finite linear opening mode-I crack. In the context of the fractional order theory of generalized thermoelasticity proposed by Sherief et al., we focus on investigating the dynamic response and the governing equations of the problem are formulated and solved by means of normal mode analysis. The distributions of the considered non-dimensional temperature, displacement and stress are obtained and illustrated graphically. The effects of fractional order parameter, rotation, crack dimension on the variations of the considered variables are investigated, and the results show that this parameter has significant influence on the variations of the considered variables. [ABSTRACT FROM AUTHOR]

AbstractFunctionally graded materials (FGMs) stand as one of the most representative composite materials due to the superior thermal resistance in non-isothermal environment. On another front, the applicability of integer-order heat conduction models is increasingly questionable because the heat transfer shares the history-dependent property at time microscale. It is noted that the small-scale effect of elastic deformation has become significant due to the development of micro-devices. To capture the small-scale effect of elastic deformation and the memory-dependent effect of heat conduction in the FGM microstructures, as a first attempt, the present study focuses on developing a thermoelastic model by incorporating the fractional-order dual-phase-lag (FODPL) heat conduction model and the Eringen’s nonlocal model. Moreover, the extension of the Caputo definition, i.e., the Tempered-Caputo (TC) definition of fractional derivative ruling out singular kernel is adopted to depict the memory-dependent effect of the heat conduction. Then, the modified model is used to investigating the dynamic response of a FGM spherical microshell subjected to a sinusoidal thermal-mechanical loading. The corresponding governing equations are formulated and then solved by Laplace transform techniques. Some parametric results are demonstrated to display the influences of the fractional-order parameter, the nonlocal parameter and the power-law index on the considered physical quantities. [ABSTRACT FROM AUTHOR]

AbstractThis work aims to study the nonlinear transient coupled thermo-electromechanical dynamic responses of the piezoelectric structure with the high-order temperature-dependent material properties. The multi-field coupling nonlinear model is established based on the non-Fourier thermoelasticity theories by introducing the function of high-order temperature dependency of the arbitrary material property. The virtual work principle and the nonlinear finite element approach are proposed to investigate the two-dimensional case of the orthotropic rectangular piezoelectric plate of the crystal class mm2 subjected to the zonal transient heating loads. The influences of the high-order temperature-dependent material parameters on the structural responses and wave propagations are discussed. [ABSTRACT FROM AUTHOR]

Nowadays, the nanosandwich structure stands as one of the most promising candidates for nanodevices and nanocomposites (e.g., nanogenerator, nano-energy harvester) due to its superior mechanical properties. The size-dependent response analysis of nanosandwich structure under extreme in-service environment is of great importance for its fabrication and exploitation. This motivates us to study the transient responses of nanosandwich structure subjected to the symmetrical transient thermal and chemical potential shock loads, which are both imposed on its upper and lower bounding surfaces. It is further assumed that thermal contact resistance and diffusional contact impedance at the interface of each two adjacent layers are zero with ideal adhesion. For each isotropic homogeneous elastic layer, the governing equations are formulated in the context of size-dependent generalized thermoelastic diffusion theory and then are solved by using Laplace transformation techniques. The effects of elastic nonlocal parameter, fractional order parameters as well as material characteristic parameters on structural transient responses are also analyzed and discussed. The present study not only provides a comprehensive understanding of the size-dependent thermoelastic diffusion coupling of nanosandwich structure, but also offers basic guidelines for optimal design. [ABSTRACT FROM AUTHOR]

In the context of a memory-dependent generalized thermoelasticity, the thermal-induced transient response in an infinite elastic body containing a spherical shell is investigated. A thermal shock is applied on the inner surface of the spherical shell. The infinite body and the spherical shell are assumed to be isotropic but two dissimilar materials. By using an analytical technique based on the Laplace transform along with its numerical inversion, the governing equations of the problem are solved and the non-dimensional physical quantities in the two materials, i.e., temperature, displacement and stress, are obtained and illustrated graphically respectively. In simulation, the accuracy of memory-dependent derivative (MDD) is verified by degrading the present model into L-S model to compare the results obtained from the cases with interfacial thermal resistance and without interfacial thermal resistance. In addition, the effects of the different kernel functions as well as the ratios of the two materials, including the ratios of the density, the thermal-conductivity and the time-delay, on the distributions of the considered variables are obtained and demonstrated graphically respectively. [ABSTRACT FROM AUTHOR]

Viscoelastic materials (e.g. rubber, resin, concrete skeleton, etc.) serve as one of the most promising candidate for new multifunctional materials due to their excellent rheological properties, as they are widely used in biology, petroleum industry, chemical and civil engineering, and other areas. The interaction of high-heat-flux loads (e.g. ultrafast pulsed lasers) with viscoelastic materials is a hot topic of numerous theoretical and experimental studies. Nevertheless, classical and extended generalized thermoviscoelasticity models available in literatures cannot characterize the strain relaxation behavior for viscoelastic materials. In this work, the time-based fractional thermoviscoelasticity model is further extended with a new consideration of fractional order strain. The governing equations involving strain and thermal relaxation times as well as fractional order parameters of strain and heat flux are formulated and are also applied to investigate thermal shock problem of a transient heated thick viscoelastic plate of infinite extent. With the aids of Laplace transformation methods, the transient solutions are also obtained. Finally, the effects of fractional order parameters of strain and heat flux on the transient thermoviscoelastic responses are studied and discussed. [ABSTRACT FROM AUTHOR]

The dynamic response of a one-dimensional thermo-piezoelectric problem with variable material properties is investigated in the context of fractional order theory of thermoelasticity. The system of governing equations for the thermo-piezoelectric problem is formulated and then solved by means of Laplace transform together with its numerical inversion. The distributions of the considered non-dimensional displacement, temperature, and stress are obtained and illustrated graphically. The effects of fractional order parameter and temperature-dependent properties on the considered quantities are investigated and the results show that they have significant influence on the variations of the considered quantities. [ABSTRACT FROM AUTHOR]

The dynamic response of a two-dimensional generalized thermal shock problem is investigated in the context of the fractional order theory of thermoelasticity proposed by Sherief et al. To demonstrate the solution process, a thermoelastic half-space subjected to a thermal shock on its bounding surface is considered in detail. The governing equations for the problem are formulated and then solved by normal mode analysis. The distributions of the considered nondimensional temperature, displacement, and stress are obtained and illustrated graphically. The effect of fractional order parameter on the variations of the considered variables is investigated, and the results show that the fractional order parameter has significant influence on the variations of the considered variables. [ABSTRACT FROM AUTHOR]

The transient thermo-piezoelectric response of a functionally graded piezoelectric rod subjected to a moving heat source is investigated in the context of fractional order theory of thermoelasticity proposed by Sherief. The material properties of the functionally graded piezoelectric rod are assumed to vary exponentially along the length, except for the thermal relaxation time and the specific heat, which are taken to be constant. To solve the governing equations of the problem, Laplace transform is applied, eliminating the time effect; the analytical solutions of the displacement, stress, temperature, and electric field in Laplace domain are obtained. Subsequently, the solutions of the considered variables in time domain are obtained by numerical Laplace inversion and illustrated graphically. In calculation, the effect of the fractional order parameter on the variations of the considered variables is presented. [ABSTRACT FROM PUBLISHER]

The dynamic response of a piezoelectric-thermoelastic rod made of piezoelectric ceramics (PZT-4) subjected to a moving heat source is dealt with in the context of the fractional order theory of thermoelasticity. The piezoelectric-thermoelastic governing equations for the problem are formulated and then solved by means of Laplace transform together with its numerical inversion. The distributions of the considered nondimensional temperature, displacement, stress, and electric potential are obtained and illustrated graphically. The effects of fractional order parameter and the velocity of heat source on the variations of the considered variables are investigated, and the results show that they have significant influence on the variations of the considered variables. The present investigation could be helpful for better understanding the multi-field coupling effect of mechanical, electric, and thermal fields in real piezoelectric ceramics structures, and provide some guidelines in the optimal design of actuators or sensors made of piezoelectric ceramics serving in a thermoelastic environment. [ABSTRACT FROM PUBLISHER]

Abstract In recent years, the application of porous materials in practical engineering has become increasingly common. Under extreme thermal conditions, how to accurately describe the heat conduction and structural response of porous materials is a key issue in the structural safety and functional design of porous materials. Among them, it is particularly important to consider the size-dependent and memory-dependent effects for small-sized structures or microdevices of porous materials. To address these issues of porous structures and to guide their applications as well as optimization, this paper first investigates the thermoelastic transient response of porous microplates subjected to thermal and stress shocks at the left boundary based on the Atangana-Baleanu (AB) fractional-order generalized thermoelastic theory by considering nonlocal effects and fractional-order strain, which is combined with the thermoelasticity theory of porous materials and the dual-phase-lag (DPL) heat conduction model. The governing equations are then established and solved using the Laplace transform and its numerical inversion. Finally, the effects of newly defined fractional order parameters, nonlocal parameters and the initial magnitude of the mechanical shock on the dimensionless temperature, volume fraction field, displacement and stress distribution are discussed and displayed graphically. [ABSTRACT FROM AUTHOR]

A two-dimensional generalized electromagnetothermoelastic problem for a half-space with diffusion is investigated in the present work. The problem is formulated in the context of the generalized thermoelastic diffusion theory. The half-space is initially placed in an external magnetic field with constant intensity, and its bounding surface in contact with a permeating substance is taken to be traction free and subjected to a time-dependent thermal load. The chemical potential is also assumed to be known function of time on the bounding surface. The half-space deforms because of the thermal load, and due to the application of magnetic field, there results in an induced magnetic field and an induced electric field in the half-space. The system of Maxwell's equations is given and the generalized electromagnetothermoelastic diffusive coupled governing equations are established. To solve the formulated equations, normal mode analysis is adopted and the exact expressions for the non-dimensional temperature, displacement, stress, induced magnetic field, induced electric field, and chemical potential and concentration are obtained and represented graphically. [ABSTRACT FROM AUTHOR]

A two-dimensional coupled problem in electromagneto-thermoelasticity for a thermally and electrically conducting half-space solid whose surface is subjected to a time-dependent heat is studied in this paper. The problem is in the context of the Green and Lindsay's generalized thermoelasticity theory with two relaxation times. There acts an initial magnetic field parallel to the plane boundary of the half-space. The medium deforms because of heat, and due to the application of the magnetic field, there results an induced magnetic field and an induced electric field in the medium. The Maxwell's equations are formulated and the electromagneto-thermoelastic coupled governing equations are established. The normal mode analysis is used to obtain the exact expressions for the considered variables. The distributions of the considered variables are represented graphically. From the distributions, it can be found the wave type heat propagation in the medium. [ABSTRACT FROM AUTHOR]

AbstractThe extraordinary properties of graphene nanoplatelets (GPLs) have attracted great attention in the thermomechanical behaviors. Additionally, thermoelastic damping (TED), as a dominant intrinsic dissipation mechanism, is a major challenge in optimizing high-performance micro/nano-resonators. However, the classical TED models fail to explain the thermomechanical behavior considering the influences of the small-scale effect and the memory-dependent effect. To fill these gaps, the present study aims to investigate TED analysis of functionally graded (FG) microplate resonators reinforced with GPLs in the frame of the modified strain gradient theory and the fractional dual-phase-lag heat conduction model. Four patterns of GPLs distribution namely the UD, FG-O, FG-X, and FG-A pattern distributions are taken into account, and the effective material properties of the plate-type nanocomposite are evaluated based on the Halpin–Tsai model. The energy equation and the motion equation in the Kirchhoff microplate model are solved, and then, the closed-form analytical expression of TED is obtained by complex frequency technique. A detailed parametric study has been conducted to discuss the influence of the material length-scale parameter, the fractional-order parameter, and the total weight fraction of GPLs on the TED. The results demonstrated that the energy dissipation of FG microplate resonators reinforced with GPLs is determined by the small-scale effect, the memory-dependent effect, and the total weight fraction of GPLs. This article provides a theoretical approach to predict TED in the design of FG microplate resonators reinforced with GPLs with high performance. [ABSTRACT FROM AUTHOR]

AbstractThermo-electromechanical coupling analysis at micro and nano temporal and spatial scales becomes significantly important with extensive application of ultrafast heating technology to micro/nano-machining and manufacturing of piezoelectric micro/nano-devices, where the size effects in heat conduction and elastic deformation remarkably increase. This article aims to establish a new nonlocal piezoelectric thermoelasticity theory based on newly developed model of Eringen-type nonlocal single-phase-lag heat conduction via Eringen’s nonlocal continuum mechanics. The proposed model is applied to analyze the thermo-electromechanical responses of piezoelectric nanorod by Laplace transformation technique. The effects of nonlocal characteristic lengths on wave propagations and structural transient response are evaluated and discussed. [ABSTRACT FROM AUTHOR]