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In response to a series of engineering disasters encountered during the excavation and support construction of loess tunnels, considering the issues of water enrichment in surrounding rock induced by excavation disturbance and system bolt failure, drawing on the concepts of lime pile composite foundation and composite bearing arch, and based on the principle of the New Austrian Tunneling Method (NATM) that fully mobilizes and leverages the self-supporting capacity of surrounding rock, this study comprehensively considers the wetting and stress adjustment processes of the surrounding rock after excavation disturbance in loess tunnels. By adopting the technical principle of "water absorption and densification of shallow surrounding rock, suspension and anchoring of deep surrounding rock, and composite arch bearing", a new type of water-absorbing, densifying, and anchoring bolt was developed that can reduce the water content of surrounding rock while enhancing its resistance. To further investigate the water absorption, densification effect, and pull-out bearing characteristics of this new bolt, laboratory model tests were conducted, examining the temperature, pore water pressure, densification stress of the soil around the bolt, as well as the physical properties of the soil in the consolidation zone. The test results indicate that a cylindrical heat source forms around the water-absorbing, densifying, and anchoring bolt, significantly inducing the thermal consolidation of the surrounding soil. The variations in temperature, pore water pressure, and densification stress of the soil around the bolt truly reflect the qualitative patterns of hydro-thermal–mechanical changes during the water absorption, curing, and exothermic reaction processes. The water absorption and densification segment of the bolt effectively enhances the density of the soil in the water absorption, densification, and consolidation zone, improving soil strength parameters. Compared to traditional mortar-bonded bolts, the water-absorbing, densifying, and anchoring bolt exhibits a greater pull-out bearing capacity. The research findings provide important guidance for the theoretical design and engineering application of this new type of bolt. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GPLs) are considered to be a desirable reinforcing nanofillers for nanocomposite materials owing to their superior thermo‐mechanical properties. Meanwhile, thermoelastic damping (TED), as a dominant intrinsic dissipation mechanisms, is a major challenge in optimizing high‐performance micro/nano‐resonators. Nevertheless, the classical TED models fail at the micro/nano‐scale due to without considering the influences of the size‐dependent effect and the thermal lagging effect. The present work focuses on investigating TED analysis of functionally graded (FG) microplate resonators reinforced with GPLs based on the modified coupled stress theory (MCST) and the Moore–Gibson–Thompson (MGT) heat conduction model. Four patterns of GPLs distribution including the UD, FG‐O, FG‐X and FG‐A pattern distributions are taken into account and the effective mechanical properties of the plate‐type nanocomposite are evaluated based on the Halpin–Tsai model. The energy equation and the transverse motion equation in the Kirchhoff microplate model are formulated, and then, the closed‐from analytical solution of TED is solved by complex frequency method. The influences of the various parameters involving the material length‐scale parameter, the thermal phase lag of the heat flux and the total weight fraction of GPLs on the TED are discussed in detail. The obtained results show that the effects of the modified parameter on the TED are pronounced. This results provide a more reasonable theoretical approach to estimate TED in the design of FG microplate resonators reinforced with GPLs with high performance. [ABSTRACT FROM AUTHOR]

Functionally graded (FG) laminated micro/nanostructures reinforced with graphene nanoplatelets (GPLs) stand as one of the most promising candidates for composite structures due to the excellent thermo-mechanical properties. Meanwhile, thermoelastic damping (TED) is one of the key factors to lower quality factor in micro/nanoresonators. Nevertheless, the classical TED models fail to explain the thermo-mechanical behavior considering the influences of the size-dependent effect and the thermal lagging effect. To fill these gaps, the present study aims to investigate TED analysis of FG laminated microplate resonators reinforced with GPLs in the frame of the modified strain gradient theory and the three-phase-lag heat conduction model. Four patterns of GPLs distribution including 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 according to the Halpin–Tsai model. The energy equation and the motion equation based on the Kirchhoff microplate model are solved, and then, the closed-from 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 phase-lag parameters and the total weight fraction of GPLs on the TED. Results demonstrated that the energy dissipation of FG laminated microplate resonators reinforced with GPLs is determined by the size-dependent effect, the thermal lagging effect and the total weight fraction of GPLs. This results are helpful to the design of FG laminated microplate resonators reinforced with GPLs with high-performance for theoretical approach. [ABSTRACT FROM AUTHOR]

The accurate representation of real floor behavior is crucial for assessing human-induced vibration serviceability. Many researchers focus on developing computational models and field testing to reflect actual serviceability conditions. Although traditional boundary conditions are commonly used, limited attention has been given to optimizing these conditions. To begin with, this paper introduced semirigid boundary conditions into a finite-element model of the floor and optimized physical parameters and boundary constraint stiffness using the simulated annealing-particle swarm optimization (SA-PSO) method, resulting in a more realistic computational model. Subsequently, a random crowd load model was established by combining the social force model (SFM) and the pedestrian load model, and a random crowd-floor mutual coupling calculation model was established based on the improved pedestrian biomechanical model. In addition, the mode shape functions of the floor with semirigid boundary conditions were obtained by extracting the optimized mode shape vector of the floor and using cubic spline interpolation. The dynamic response of the floor was computed using the modal analysis method, and the accuracy of the suggested method and model was verified by experiment. Furthermore, the effect on the vibration serviceability of the floor was analyzed under crowd walks randomly on the floor with different boundary conditions both before and after optimization. This study revealed: (1) achieving a computational model consistent with real floors requires optimization of relevant parameters and boundary conditions, reducing the error in floor frequency from 39.48% to 5.44% compared to measured results. (2) The human-induced vibration serviceability for existing floors may be misjudged by using traditional boundary conditions. The mean value of peak acceleration of floor with semirigid boundary conditions increased by 35.92%, with a 42% increase in the probability of serviceability problems compared to the SSCC boundary. (3) High-frequency floors also experience human-induced vibration serviceability issues. For a floor with a fundamental frequency of 10.3540 Hz, simulation and experimental results during five-person random walks indicate that peak acceleration at the middle position of the floor exceeds serviceability limits. [ABSTRACT FROM AUTHOR]

Integer-order thermoviscoelastic models may fail to give an accurate description of the thermomechanical behavior of viscoelastic materials, which inherently have the memory-dependent feature. Meanwhile, with the miniaturization of devices, the small-scale effect on elastic deformation is becoming increasingly significant. To better describe the memory-dependent effect and the small-scale effect in viscoelastic microstructures, this work focuses on developing a refined nonlocal thermoviscoelastic model by incorporating the fractional-order dual-phase-lag (DPL) heat-conduction model and the fractional-order strain model. Moreover, the Caputo–Fabrizio (CF) definition and the Tempered-Caputo (TC) definition of the fractional derivative without a singular kernel as well as the extension of the Caputo definition are adopted to reflect the memory-dependent effects of the heat conduction and the stress–strain relation for the first time, respectively. Then, this new model is applied to investigate the transient response of a viscoelastic microplate subjected to a sinusoidal thermal loading. The governing equations involving the modified parameters are formulated and then solved by the Laplace-transform method. Some parametric results are demonstrated to display the impacts of the fractional-order parameter, the fractional-order strain parameter and the nonlocal parameter on the considered physical quantities. The results show that the nonlocal effect and the memory-dependent effect strongly depend on the viscoelastic microstructure characteristics in a thermal environment. [ABSTRACT FROM AUTHOR]

With the rapid development and applications of micro/nano electromechanical systems in engineering fields, piezoelectric materials have been widely used in these systems due to their excellent physical and mechanical properties. Generally, these systems work in complex thermoelastic environments, to depict the thermal-electro-mechanical behaviors of piezoelectric material structures at microscale, the existing theories need to be developed due to the arising size-dependent effect, thermal relaxation effect and flexoelectric effect etc. To this end, the present work intends to generalize the size-dependent theories by considering the thermal-electro-mechanical coupling behaviors in piezoelectric material structures at microscale. Based on the nonlocal strain gradient theory and the generalized heat conduction model, a new model is established and the corresponding constitutive equations and the governing equations of equilibrium are derived. To illustrate the application of this new model, a piezoelectric micro-beam with flexoelectricity is considered and the closed form solutions of bending deflection and the free vibration response are obtained in terms of the boundary conditions. Based on the numerical results, the size-dependent effect, the piezo-flexoelectric effect and the thermal-lagging effect on the bending and vibration responses of the microbeam are examined and illustrated graphically. This work may be potentially helpful for the efficient, optimized and adaptive designs of the NEMS/MEMS devices. [ABSTRACT FROM AUTHOR]

With their abilities to induce electric charge, stress or deformation in response to external forces as well as the ease of fabrication, design flexibility and excellent electromechanical properties, piezoelectric materials have been widely used in actuators, sensors and even in nano/micro-electro-mechanical systems. With the rapid advancement of nano/micro-technology, from the perspective of theoretical analysis, the priority is to develop applicable models to describe the piezoelectric-thermoelastic responses of piezoelectric nano/micro-structures suffering transient heat conduction by taking the size-dependent effect and the memory-dependent effect into consideration. In this work, a new model based on the existing piezoelectric-thermoelastic model is established by introducing the nonlocality into the constitutive equations and the memory-dependent derivative into Moore-Gibson-Thompson (MGT) heat conduction equation respectively. Then, this new model is applied to investigating the dynamic responses of a piezoelectric nanoplate subjected to thermal shock. The corresponding governing equations are formulated and then solved by Laplace transform and its numerical inversion. In calculation, the influences of the time delay factor and the kernel function of MDD and the non-local parameter on the thermal, electric and elastic fields in the piezoelectric nanoplate are examined. Meanwhile, the predictions of transient response among different thermoelastic models are compared. The numerical results are illustrated graphically and discussed in detail. The obtained results show that MDD has a significant effect on the transient response, where the effect of the kernel function is more pronounced. This work may provide a theoretical reference for strength design, thermal protection and thermal processing strategies for piezoelectric nanodevices. [ABSTRACT FROM AUTHOR]

Achieving renewable power for self‐powered electronic devices such as micro/nano‐electro‐mechanical systems is attractive in the fields of energy resources and environment, in this regard, dielectric material structures with excellent energy storage and electromechanical responses have stimulated a surge of research interest. However, in the micro/nanoscale filed, the existing thermo‐electromechanical continuum theories are not capable of fully and effectively characterizing the arising effects, for example, size‐dependent effect and heat lagging effect, etc. To further develop the existing theories, a theoretical prototype for piezo‐flexoelectricity by incorporating strain gradient effect and dual‐phase‐lag heat conduction model is proposed for the first time in this study, and then this proposed model is applied to investigating the energy harvesting performances of a piezo‐flexoelectric micro‐beam under piezoelectric‐thermoelastic coupling. In terms of the differential form of two‐phase elasticity and Hamilton's principle, the governing equations and the boundary conditions for the transverse vibration of a micro‐beam based on the Euler–Bernoulli beam model are derived. By means of the assumed mode method, the influences of the flexoelectricity, the load resistance and the strain gradient on voltage and output power are examined. From the obtained results, it can be aware of that this study not only presents the piezoelectric‐thermoelastic coupling effect of piezo‐flexoelectric configuration in microscale field, but also presents that a piezo‐flexoelectric system at microscale can generate higher power than that reported in previous works. It is hoped that this study could provide some guidelines in designing and optimizing dielectric energy harvesters of micro/nano electronic devices. [ABSTRACT FROM AUTHOR]

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]

This article, published in the International Journal of Applied Mechanics, discusses a new theory of fractional-order rate-dependent piezoelectric thermoelasticity and its application in analyzing the structural transient response of smart piezoelectric composite laminates. The authors develop unified forms of fractional-order strain and heat conduction by adopting different types of fractional derivatives. They establish a fractional-order rate-dependent piezoelectric thermoelasticity theory and derive constitutive and governing equations using an extended thermodynamics framework. The theory is then applied to investigate the dynamic thermo-electromechanical responses of smart piezoelectric composite laminates with imperfect interfacial conditions. The influences of different fractional derivatives, imperfect interfacial conditions, and materials constants ratios on wave propagations and structural thermo-electromechanical responses are evaluated and discussed. [Extracted from the article]

Nano-batteries have been widely used in electric vehicles, new energy, and aerospace engineering since their high energy density, low manufacturing cost, and long cycle life. In recent years, there have been many papers that contributed to investigate the diffusion-mechanical coupling problems under non-uniform molar concentration environments (e.g., rapid charging, etc.). Nevertheless, the memory dependence of strain relaxation and mass transfer has not been considered yet. This paper aims to construct a unified fractional-order non-Fick mechanical-diffusion coupling model by introducing the fractional derivatives of the Caputo (C), Caputo–Fabrizio (CF), Atangana–Baleanu (AB), and Tempered-Caputo (TC) types. The proposed theoretical model is applied to investigate structural transient dynamic responses of multilayered composite laminates with imperfect interfacial conditions by Laplace transformation approach. The influences of different fractional derivatives, imperfect interfacial conditions, and materials constants ratios on the wave propagations and dynamic mechanical-diffusion responses are evaluated and discussed in detail. [ABSTRACT FROM AUTHOR]

Functionally graded sandwich micro/nano-structures have attracted great attention due to the capability to resist high noise and thermal stress in a non-isothermal environment. Additionally, the design of high quality-factor micro/nano-resonators requires accurate estimation of their thermoelastic damping. However, the classical thermoelastic damping models fail at the micro/nano-scale due to the influences of the size-dependent effects related to heat transfer and elastic deformation. This work aims to investigate the influences of the size-dependent effects on the thermoelastic damping of functionally graded sandwich micro-beam resonators by combining the nonlocal dual-phase-lag heat conduction model and the nonlocal elasticity model. It is assumed that the functionally graded sandwich micro-beam resonators consist of a ceramic core and functionally graded surfaces. The energy equation and the transverse motion equation are derived. The analytical expression of thermoelastic damping is obtained by complex frequency method. Numerical results are analyzed for the effects of the thermal nonlocal parameter, the elastic nonlocal parameter, the power-law index, and the vibration modes on the thermoelastic damping of functionally graded sandwich micro-beam resonators. The results show that the thermoelastic damping of functionally graded sandwich micro-beam resonators can be adjusted by the suitably modified parameters, which strongly depends on the double nonlocal effects and the power-law index. [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]

This study presents a new strain measurement method based on an external symmetrical compensation bridge (ESCB) composed of strain gauges with a four-wire configuration. Unlike the traditional strain measurement methods, this method includes two features: first, utilising the four-wire configuration to eliminate measurement errors that occur due to large space-varying thermal and field imbalances of long signal wires during operation, and second, utilising two independent quarter-active sub-bridges with a four-wire configuration composed of ESCB to eliminate the errors that occur due to the large time-varying cryogenic temperature and magnetic field. This method was validated and used on a large-scale NbTi superconducting dipole magnet detector during the cooling, excitation, and quench tests. The strains measured using the ESCB were also compared with those measured using a traditional half-active compensation bridge. The observations showed that the ESCB method can overcome the interference of the temperature gradient and electromagnetic field of long wires during both cooling and electromagnetic excitation processes. In addition to the abrupt strain signal appearing when a quench occurred, high amplitudes occurring at high frequencies were observed at the onset of a quench based on the strain spectra analysis. Thus, the strain spectra are expected to provide a novel means for early quench warning. [ABSTRACT FROM AUTHOR]

More realistic results of the random crowd-structural interaction dynamic response calculations are crucial for structural vibration analysis and control. And ignoring interactions is considered a conservative approach. This paper analyzes the effect of obstacles and semi-rigid boundary conditions on the random crowd-structure interaction vibration of the floor. The social force model is used to simulate crowd walking randomly in the room, and simulation results are matched with the dynamic calculation of the floor, thus establishing the time-varying dynamic calculation model of crowd-structure interaction. The differential quadrature method and mode analysis method are used to solve the dynamic equations. In addition, the effect of crowd random walking in an environment with obstacles on the time-varying parameters and dynamic response of the floor is discussed. The results show: (a) With the random walking of pedestrians, the floor fundamental frequency first decreases and then increases compared with the no-load, while the change of damping ratio is the opposite. Furthermore, the variation of floor fundamental frequency and damping ratio is greater in the empty classroom (without obstacles) than in the discussion room layout (with obstacles) due to the obstacles. (b) Analyzing the variation of the acceleration response of the floor under the two layouts, it can be found that the installation of obstacles can improve the human-induced vibration of the floor. (c) The vibration problem of the floor can be effectively improved by changing the stiffness ratio in semi-rigid constraint, which provides another idea for the vibration control of the floor. [ABSTRACT FROM AUTHOR]

As a main source of energy dissipation, thermoelastic damping (TED) cannot be ignored in designing resonators with high-quality factor. However, due to the size-dependent effect and the thermal relaxation, the TED models formulated in the classical theory are no longer able to accurately estimate the energy dissipation in the micro-/nano-resonators. To fill theses gaps, the present work aims at developing a new TED model for micro-plate resonators based on the modified couple stress theory incorporating memory-dependent derivative heat conduction model. The corresponding governing equations are derived, and the analytical solution for the TED is obtained. In order to discover the variation law of TED of micro-plate resonators, the numerical results corresponding to different materials and different theories are illustrated and compared. In calculation, the effects of the material parameters, the boundary conditions, the length scale parameters and the length on the peak value as well as the critical thickness of TED are further studied. It is expected that this novel model may provide a theoretical basis for designing high-performance micro-plate resonators under complex working conditions. [ABSTRACT FROM AUTHOR]

The applicability of the Green–Naghdi (GN-III) thermoelasticity is increasingly questionable because the theory predicts that heat transfers with an infinite speed. To address this deficiency, the three-phase-lag (TPL) thermoelasticity was developed by introducing the lagging times into the GN-III thermoelasticity. On another front, the small-scale effect on elastic deformation cannot be ignored with the miniaturization of structures or devices. Meanwhile, the memory-dependent feature of heat transfer process in the case of ultrafast heating cannot be described by the integer-order heat conduction models due to the inherent local limited definition. To capture the small-scale effect and the memory-dependent effect of the microstructures, as a first attempt, the present work focuses on developing a TPL thermoelastic model by considering the memory-dependent derivative (MDD) heat conduction model and Eringen's nonlocal model. Then, the refined model is used to investigate the transient characteristics of a spherical microshell induced by thermal and mechanical loadings. The governing equations containing the modified parameters are derived and then solved by Laplace transform method. Some parametric results are demonstrated to display the effects of the time-delay factor, the kernel function, and the nonlocal parameter on the considered physical quantities. [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]

Ultra-slow relaxation process of polymers has the memory-dependent feature, integer-order thermoviscoelastic models may fail to describe the dynamic behaviors of viscoelastic structures accurately. Additionally, it is noticed that the small-scale effect of elastic deformation and heat conduction in a non-isothermal temperature environment is becoming significant due to the development of micro-devices. To better capture the memory-dependent effect and the small-scale effect of viscoelastic micro-structures in heat transfer environment, as a first attempt, present work focuses on developing a refined fractional Kelvin-Voigt thermoviscoelastic model by incorporating the nonlocal dual-phase-lag (NDPL) heat conduction model and the modified coupled stress theory (MCST). Then, the model is applied to investigating the transient response of a polymer microbeam subjected to a harmonic thermal loading. The governing equations involving the modified parameters are formulated and then solved by Laplace transform method. Some parametric results are demonstrated to display the impacts of the nonlocal thermal parameter, the material length-scale parameter and the fractional-order parameter on the considered physical quantities. The results show that the small-scale effect and the memory-dependent effects strongly depend on the polymer micro-structure characteristics in thermal environment. [ABSTRACT FROM AUTHOR]

Mechanical-diffusion coupling analysis at micro/nanotemporal and spatial scale has aroused great research interests with flourishing development of nanobattery system and fast rising of rapid charging technology, where the spatial nonlocal effects of mass transfer and elastic deformation as well as the influences of temporal nonlocal effects of mass transport (i.e., the phase laggings of diffusion flux vector and molar concentration gradient) will remarkably increase. In such cases, however, the accurate prediction of mechanical-diffusion responses is challenged: Firstly, the existing non-Fick diffusion–elasticity models are established by merely introducing mass diffusion model associated with the time rate of diffusion flux (i.e., phase laggings of diffusion flux); secondly, the spatial nonlocal effect of mass transfer is still not considered in the current on dual-phase-lag diffusion model. This work aims to develop a non-Fick diffusion–elasticity based on a new nonlocal dual-phase-lag diffusion model, which fully incorporates spatial and temporal nonlocal effects of mass transport. New constitutive and field equations are strictly derived via nonlocal continuum mechanics. To illustrate its application values, a one-dimensional isotropic homogeneous thin layer of finite thickness subjected to transient shock loadings of molar concentration is investigated. Dimensionless results are graphically presented to illustrate the effects of both nonlocal mass transfer and nonlocal elasticity on diffusive wave propagation and mechanical-diffusion responses. [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]

In order to obtain the transient thermoelastic diffusion responses of porous materials heated by the ultrashort pulse laser, the focus of this work is to establish a generalized thermoelastic diffusion theory considering strain, thermal and diffusion relaxation effect within the thermodynamic framework. Firstly, we derive the governing equations of the linear generalized thermoelastic diffusion theory of porous media in the context of the thermodynamic laws. Secondly, the copper material with voids occupying a half-space heated by the ultrashort pulse laser is investigated based on the built theory. The bounding plane is assumed to be traction free and impacted by a non-Gaussian laser beam. The exact solutions of the governing equations are obtained by Laplace transformation and the numerical inverse Laplace transformation. Finally, the effect of strain relaxation factor, thermal relaxation factor, fractional order parameter, and laser parameters on non-dimensional temperature, displacement, stress, volume fraction field, and chemical potential is studied and presented graphically. [ABSTRACT FROM AUTHOR]

The relaxation process of viscoelastic materials has the memory-dependent effect, while integer-order thermo-viscoelastic models may be challenged to predict precise thermal–mechanical behaviors in solving transient problems of viscoelastic materials in a heat transfer environment. It is found that the fractional-order viscoelastic models fit well with the experimental data from creep and relaxation tests. Additionally, the size-dependent effect on elastic deformation is becoming an issue of great importance recently due to the development of small-scale devices. To capture the memory-dependent and size-dependent effects, the present work aims to formulate a modified fractional-order thermo-viscoelastic model at small-scale for the first time by simultaneously incorporating the effects of the unified definition of the fractional-order parameter, the unified definition of the fractional-order strain parameter and the nonlocal parameter based on the generalized thermo-viscoelastic theory. Then the dynamic response of a viscoelastic microplate under a thermal shock is studied by using the modified fractional-order thermo-viscoelastic model. The corresponding governing equations are formulated and solved by the Laplace transform and its numerical inversion. In conclusion, the influences of the fractional-order parameters, the fractional-order strain parameters and the nonlocal parameters on the variations of the considered quantities are presented and discussed in detail. The obtained results show that these parameters significantly influence the variations of all the considered quantities. [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]

Thermotropic yield characteristic of the ceramic–alloy composite beam induced by a unilateral heat source is investigated by using the Hamilton principle and the variation method based on the first‐order shear deformation theory. The mathematical essence of the yield problem of the composite beam is that the variation of the Lagrange function of the system to the space coordinates equals zero. The Tamura–Tomota–Ozawa model and the linear rule of mixtures are used to simulate the composite material properties of functionally graded material (FGM), and the constitutive equations are established with the linear hybrid hardening model. The von‐Mises yield condition is introduced to judge whether the beam enters the yield state. The governing equations are established by using the Hamilton principle and variation method. The thermotropic yield surfaces, the yield stresses, and the critical temperature rises of the yield functionally graded beam are obtained, and the deflections of the beam are calculated by analytical method. The results reveal that the yield interfaces, the yield stresses, the critical temperature rises, and the deflections of the beam vary with material parameters, geometric parameters, and so on. [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 stress–strain relation in classical viscoelasticity models is increasingly questionable in solving transient problems of viscoelastic materials. It is found that the fractional order viscoelastic models fit well with the experimental data from relaxation tests. Meanwhile, although the strain rate is small, which is often neglected in thermo-viscoelasticity models, it is not reasonable to neglect the strain rate in the case of ultrafast heating. In this work, a new generalized fractional order thermo-viscoelastic theory with fractional order strain is formulated by extending the existing thermo-viscoelastic theory. Then, this new theory is applied to investigating the dynamic response of an infinite thermo-viscoelastic medium containing a spherical cavity. The infinite medium is subjected to a thermal shock and a mechanical shock simultaneously at the inner surface of the cavity. The corresponding governing equations are formulated and then solved by the Laplace transform together with its numerical inversion. The distributions of the non-dimensional temperature, displacement, radial stress, and hoop stress are obtained and illustrated graphically. In calculation, the effects of the fractional order parameter, fractional order strain parameter, and mechanical relaxation parameter on the variations of the considered variables are presented and discussed in detail. [ABSTRACT FROM AUTHOR]

With the rapid evolution of small‐scale devices, the effect of size dependence on elastic deformation becomes more and more obvious. Furthermore, the physical processes usually involve memory and inheritance for some anomalous diffusion that the constitutive relation does not obey the standard gradient rate. Owing to capturing the memory‐dependent effect and the size‐dependent effect, the existing thermoelastic diffusion theories cannot be applicable. To further refine the thermoelastic diffusion model for micro/nano structures, a refined nonlocal thermoelastic diffusion model is developed by combining the fractional‐order dual‐phase‐lag (DPL) heat conduction model and fractional‐order diffusion model in this paper. In addition, the Tempered‐Caputo (TC) definition is an extension of the Caputo definition without the fractional derivative of the singular kernel, which is adopted for the first time to reflect the memory‐dependent effects of heat conduction and stress–strain relationship. Then, this new model is applied to investigating the transient response of an elastic microplate subjected to a sinusoidal thermal loading. The corresponding governing equations are formulated and solved by the Laplace transform method and its numerical inversion. In calculation, the influences of the fractional‐order parameter, the tempered parameter and the nonlocal parameter on the variations of the considered quantities are presented and discussed in detail. It is expected to provide new insights into thermoelastic diffusion behaviors of structures at the micro/nanoscale. [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]

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]

In this paper, to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor (PS) nanodevice, and to further improve its working performance, a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect. Next, by using the current theoretical model, some numerical analyses and discussion about the surface effect, the corresponding critical thickness of the nanoplate, and the distributions of the physical fields (including the electron concentration perturbation, the electric potential, the electric field, the average electric displacement, the effective polarization charge density, and the total charge density) under different initial state electron concentrations, as well as their active manipulation via some external magnetic field, pre-stress, and temperature stimuli, are performed. Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment, this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect, but also assists the design of a series of multiferroic PS nanodevices. [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]

The layer-by-layer viscoelastic sandwich nanocomposites have been widely used as high-efficient shock absorbers in nano-engineering since its excellent performance in vibration isolation. Such structure often works in thermoelastic coupling condition, and a thorough and comprehensive investigation on its structural dynamic responses is imperatively needed to achieve the goal of improving heat isolation and avoiding unwanted vibration. In this work, an analytical study is conducted to investigate the structural dynamic responses of layer-by-layer viscoelastic sandwich nanocomposites based on nonlocal thermo-viscoelasticity theory. The two lateral bounding surfaces of the structure are subjected to the time-varying symmetric thermal shock loadings. It is assumed that thermal contact resistance and elastic wave impedance at the interface are zero with idealized adhesion. Governing equations of each homogeneous isotropic viscoelastic layer are derived and solved by a semi-analytical technique via Laplace transformation. The achieved results show that the heat isolation will be maximally improved and harmful thermal induced stress is lowered to some extent if properly selecting nonlocal parameters and material constants ratios. [ABSTRACT FROM AUTHOR]

Classical thermo-viscoelastic models may be challenged to predict the precise thermo-mechanical behavior of viscoelastic materials without considering the memory-dependent effect. Meanwhile, with the miniaturization of devices, the size-dependent effect on elastic deformation is becoming more and more important. To capture the memory-dependent effect and the size-dependent effect, the present study aims at developing a modified fractional-order thermo-viscoelastic coupling model at the micro-scale to account for two fundamentally distinct fractional-order models which govern the memory-dependent features of thermal conduction and stress-strain relation, respectively. Then, the modified theory is used to study the dynamic response of a polymer micro-rod heated by a moving heat source. The governing equations are obtained and solved by the Laplace transform method. In calculation, the effects of the fractional-order parameter, the fractional-order strain parameter, the mechanical relaxation parameter, and the nonlocal parameter on the variations of the considered variables are analyzed and discussed in detail. [ABSTRACT FROM AUTHOR]

Thermoelastic damping is a significant energy dissipation mechanism in nano-resonator, and exploring its feature would lay a foundation for designing high-quality nano-resonators. Due to the size-dependent effect and the non-Fourier heat conduction effect arising in structures in nanoscales, the traditional models may fail to characterize thermoelastic damping in nano-resonators. To further develop the thermoelastic damping model in small scales, a novel thermoelastic damping model is established in the present work based on the modified couple stress theory and the non-Fourier heat conduction law. Based on the novel model, the exact expression of thermoelastic damping is obtained by the complex frequency method. In calculation, the results are validated by degrading the present model to the classical model, and the effects of length scale parameters, boundary conditions, reference temperature, and vibration modes on thermoelastic damping are examined and discussed in detail. The obtained results show that the influence of the present model on the amount of thermoelastic damping and the critical thickness is significant in small scales. [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]

For thermoviscoelastic behaviors limited to ultrashort laser pulse technologies, the Fourier's heat conduction law may fail; meanwhile, new models, e.g., the fractional-order heat conduction model, have been developed to modify Fourier's law. Furthermore, it is found that the fractional-order viscoelastic models fit well with the experimental data from relaxation tests. Meanwhile, with the miniaturization of devices, the size-dependent effect on elastic deformation is becoming increasingly important. This paper addresses the transient thermoviscoelastic response of a polymer micro-rod subjected to an ultrashort laser pulse heating including the simultaneous effects of the fractional order parameter and the nonlocal parameter for the first time. The governing equations are obtained and solved by the Laplace transform method. In calculation, the influences of the magnitude of the laser intensity, the fractional-order parameter and the nonlocal parameter on the variation of the considered variables are analyzed and discussed in detail. It is hoped that the obtained results will be helpful in designing the viscoelastic micro-structures induced by a short-pulse laser heating. [ABSTRACT FROM AUTHOR]

Elastoplastic nonlinear bending behaviors of ceramic–metal composite functionally graded material (FGM) beams are investigated using the symplectic method in Hamilton system with the classical beam theory. The mechanical properties of two-phase materials are assumed to be power function of the thickness, and the elastoplastic material properties of the FGM beams are given by the linear rule of mixtures. The bilinear hardening elastoplastic constitutive equations are established based on the Tamura–Tomota–Ozawa hybrid reinforcement model. And the von-Mises yield condition is introduced to judge whether the beams have entered the plastic deformation. The canonical equations are solved by the symplectic method, and the loads and deflections are transformed into the symplectic eigenvalues and symplectic eigensolutions in symplectic space and obtained by analytical solutions. Examples of bending behaviors varying with load, deflection, slenderness ratio and power law index are presented. The obtained results reveal that the zones of the elastic bending and the elastoplastic bending as well as the peak values of the deflections vary with material and geometric properties. [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 size-dependent effect arising in micro/nano-structures has attracted considerable attention in academic and industrial communities. The theories developed to characterize such effect mainly include the nonlocal elasticity theory, the strain gradient theory, the modified coupled stress theory and the more recent nonlocal strain gradient elasticity etc. Meanwhile, the thermal-induced deformation or stress in micro/nano-structures is increasingly becoming a vital issue in their designs and applications. Nevertheless, theoretical investigations to predict the thermoelastic performances of micro/nano-structures are not so common, especially in the case of nonlocal strain gradient elasticity incorporating thermoelastic coupling effect. In present work, investigation of thermoelastic wave propagation in micro-beam is conducted in the context of the nonlocal strain gradient elasticity and the G-N theory, taking the thermoelastic coupling effect into account. The governing equations are formulated based on the Euler–Bernoulli beam model and the G-N theory. By assuming the wave-type solutions, the equations are solved and the dispersion relation between frequency and wave number and the relation between phase velocity and wave number are determined respectively. In calculation, the above two relations are fully investigated and comparisons on them under different theories are provided accordingly. Some new findings are presented and discussed in detail. It is hoped that the present work may provide some guidelines in designing and optimizing micro-structures. [ABSTRACT FROM AUTHOR]

In extreme heat transfer environments, functionally graded materials (FGMs) have aroused great concern due to the excellent thermal shock resistance. With the development of micro-scale devices, the size-dependent effect has become an important issue. However, the classical continuum mechanical model fails on the micro-scale due to the influence of the size-dependent effect. Meanwhile, for thermoelastic behaviors limited to small-scale problems, Fourier's heat conduction law cannot explain the thermal wave effect. In order to capture the size-dependent effect and the thermal wave effect, the nonlocal generalized thermoelastic theory for the formulation of an FGM microbeam is adopted in the present work. For numerical validation, the transient responses for a simply supported FGM microbeam heated by the ramp-type heating are considered. The governing equations are formulated and solved by employing the Laplace transform techniques. In the numerical results, the effects of the ramp-heating time parameter, the nonlocal parameter, and the power-law index on the considered physical quantities are presented and discussed in detail. [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]

Summary: Nanoscale piezoelectric energy‐harvesting from ambient vibration sources has great potential for practical applications in powering nanoelectronic and nano‐wireless sensors. Nowadays, the piezoelectric laminated sandwich smart nanocomposites have been extensively applied as nanogenerators, nano‐energy harvesters, and the other nano‐electromechanical devices. However, no works have thoroughly investigated the size‐dependent dynamic thermo‐electromechanical response of such structure that consider the perfect/non‐idealized interfacial conditions and piezoelectric material constants ratios. This article will address this problem based on the size‐dependent piezoelectric thermoelasticity theory by a semi‐analytical technique via the Laplace transformation. If the thermal/elastic nonlocal parameters or material constants ratios are properly selected, the results show that: (a) the electrical energy harvesting and heat isolation can be maximally improved; (b) the harmful thermal stresses will be lowered to some extent. This work not only provides a thorough and comprehensive understanding on response of piezoelectric laminated sandwich smart nanocomposites serving in non‐uniform thermal environment, but also offers basic guidelines for its thermal management and piezoelectric energy harvesting. [ABSTRACT FROM AUTHOR]