The thickness-extensional mode in layered piezoelectric plates can be inevitably interfered by some undesirable eigen-modes due to the lateral edge effect. A reported theoretical method to predict high-frequency coupled vibrations is the 2D high-order plate theory derived based on approximate dispersion relations. In this paper, based on accurate dispersion relations a novel approach called Frequency

By using the variational-asymptotic method, a universal asymptotic model for composite sandwich plates is established to achieve a great compromise between efficiency and accuracy through the synthesis of two competing theories: equivalent single-layer theories and layer-wise theories. When each layer of a sandwich structure can be individually considered as an elastic plate, and all material constitutive

Payne effect is the complex nonlinear response of filled elastomers to oscillatory loading. Although usually characterized by the decrease in the storage modulus with strain amplitude, and by the bell-shaped curve of loss modulus with strain amplitude, the response has many other peculiar features. The manner of decrease in storage modulus with strain amplitude does not change when the frequency of

We present a new methodology to derive imperfect interface models for the problems with interphase layers. The test case is potential problems, e.g., thermal conductivity, antiplane elasticity, etc. The methodology combines classical asymptotic analysis with concepts from the theory of complex-valued functions. Its major advantage over existing asymptotic approaches is the straightforward derivation

Property contribution tensors constitute basic building blocks for evaluation of effective properties of heterogeneous materials. Most of the existing results, however, are obtained for inhomogeneities of simple shapes, like ellipsoidal. With this paper we introduce open access software that allows one to calculate the components of compliance and stiffness contribution tensors of inhomogeneities of

Recently developed hard-magnetic soft (HMS) materials/structures are very attractive for applications in the fields of soft robots, biomedical devices and stretchable electronics, etc. In general, the mechanical responses of HMS structures strongly depend on the volume fraction of the embedded magnetic particles in the HMS materials. In this work, we focus on the mechanics of functionally graded hard-magnetic

Anisotropic core-shell model of a nano-grained polycrystal is extended to estimate the effective elastic stiffness of several metals of hexagonal crystal lattice symmetry. In the approach the bulk nanocrystalline material is described as a two-phase medium with different properties for a grain boundary zone and a grain core. While the grain core is anisotropic, the boundary zone is isotropic and has

This study provides a multi-step analytical model to investigate the synergistic effects of carbon black nanoparticles and micro-scale carbon fibers on the electrical conductivity of the polymer matrix multi-scale nanocomposites. In the first step, the homogenized electrical conductivity of the nanoparticle-polymer nanocomposites containing the nanoparticle agglomeration is calculated using the percolation

We focus on the mechanical strength of piezomagnetic beam-like nanosize sensors during post-buckling. An effective flexomagnetic property is also taken into account. The modelled sensor is selected to be a Euler-Bernoulli type beam. Long-range interactions between atoms result in a mathematical model based on the nonlocal strain gradient elasticity approach (NSGT). Due to possible large deformations

A nonlocal linear elastic fracture formulation is presented based on a discrete layer approach and an interface model to study cracked nanobeams. The formulation uses the stress-driven nonlocal theory of elasticity to account for the size-dependency in the constitutive equations, and the Bernoulli-Euler beam theory to define the kinematic field. Two fundamental mode I and mode II fracture nanospecimens

This work compares the transition and competitive mechanism between three types of instabilities of an incompressible dielectric tube: wrinkling, pull-in instability and electric breakdown. We also see how to select one type of instability mode on demand. First, we investigate the finite response and the wrinkling of a tube subject to a combination of applied radial voltage, torsion and axial force

We address the calculation of the effective properties of non-aging linear viscoelastic composite materials. This is done by solving the microscale periodic local problems obtained via the Asymptotic Homogenization Method (AHM) by means of finite element three-dimensional simulations. The work comprises the investigation of the effective creep and relaxation behavior for a variety of fiber and inclusion

The results of analytical and numerical studies of the internal structure of random packed beds of metal micro-particles are presented. To construct packed beds from mono- and polydisperse solid spheres, an algorithm for their random generation based on the discrete element method is used. Analysis of the structure of the packed bed includes the determination of porosity, specific surface area and

With recent ground-breaking advances, machine learning (ML) has been applied widely in numerous fields in this day and age. However, because of the application of backpropagation algorithms based on gradient descent (GD) techniques, the network of ML may be trapped in local minima, especially if its starting point is not on the same side of the global best or the network contains too many local minima

Interfacial behavior within fibrous piezoelectric composites (PZCs) may dramatically degrade the overall electromechanical performance and simultaneously vary the effective coupling moduli of these intelligent materials. In the present paper, we first recapitulate a physics-based general interfacial relation, which is rigorously derived from an ideal three-phase configuration and thus owns explicit

Traumatic brain injury (TBI) is an important cause of mortality and morbidity worldwide. Finite element models of the human head are used widely to simulate TBI loading scenarios, to improve the understanding of the mechanical pathogenesis of head trauma. The reliability of such computational models depends strongly on the accuracy of the mechanical properties of the different components of the brain

Based on the Ginzburg-Landau's theory, the free energy function of polycrystalline system was modified by introducing an extra grain boundary energy, and a new two-dimensional phase field model considering the continuous variation of temperature was proposed to investigate the grain size dependent super-elasticity (SE) and shape memory effect (SME) of nanocrystalline NiTi shape memory alloys (SMAs)

Rayleigh waves are analysed in elastic lattices incorporating inertial devices that couple in-plane displacements. The vector problems of elasticity for a triangular lattice and its long-wavelength/low-frequency continuum approximation are considered. The analytical procedure for the derivation of the Rayleigh dispersion relation is fully detailed and, remarkably, explicit solutions for the Rayleigh

In this study, the non-linear dynamic analysis of torus-shaped and cylindrical shell-like structures has been studied. The applied material is assumed as the functionally graded material (FGM). The structures are considered to be used for important machines such as wind turbines. The effects of some environmental factors on the analysis like temperature and humidity have been considered. The strain

Due to its superior modelling capabilities, there is an increasing interest in distortion gradient plasticity theory, where the role of the plastic spin is accounted for in the free energy and the dissipation. In this work, distortion gradient plasticity is used to gain insight into material deformation ahead of a crack tip. This also constitutes the first fracture mechanics analysis of gradient plasticity

In this paper, we consider the mechanism of misfit stress relaxation in lattice-mismatched core-shell nanowires (NWs) through the formation of a periodic array of misfit prismatic dislocation loops (PDLs). In doing so, we calculate and analyze the stress fields and strain energy of a PDL and the energy of pair elastic interaction between PDLs in an elastically isotropic cylinder with free surface.

Crack hitting a domain having the same elastic properties but different fracture toughness (due, for example, to thermal processing) is considered. The focus is on the choice between crack deflection by the domain and crack penetration into it. This choice is controlled by two factors: the angle at which the crack approaches the domain and the fracture toughness contrast. This problem is motivated

Experimental observation demonstrates that both negative and positive dispersion relations are possible for porous media, which classical Biot theory fails to predict and interpret. The present paper establishes a higher-order strain gradient nonlocal poroelasticity considering both the size effects and heterogeneity structure effects to describe the specific physical characteristics of material and

In this paper, a two-dimensional stress-driven nonlocal integral model is introduced for the bending and transverse vibration of rectangular nanoplates for the first time. An appropriate kernel function, which satisfies all essential properties, is proposed for two-dimensional problems in the Cartesian coordinate system. Using Leibniz integral rule and Hamilton's principle, the curvature-moment relations

A three-dimensional analysis is presented for the prediction of the behavior of periodic fiber-reinforced composites with numerous broken fibers and debonded fiber-matrix interfaces. The locations of these defects in the composite are randomly determined. The analysis is based on the representative cell method and the higher-order theory. In the framework of the representative cell method, the problem

This paper focuses on the modeling of the effect of saturation on the overall elastic properties of cortical bone. We first use micromechanical model of Salguero, Saadat & Sevostianov (2014) to model anisotropic effective elastic stiffness of drained cortical bone and then apply replacement relations (see review of Sevostianov, 2020) to evaluate effect of the saturation. The model is verified by comparison

In this paper, the mechanical behavior of multilayered small-scale beams in nonisothermal environment is investigated. Scale phenomena are modeled by means of the mathematically well-posed and experimentally consistent stress-driven integral formulation of elasticity. The present research extends the treatment in Barretta, Čanađija, Luciano, and de Sciarra (2018b) confined to elastically homogeneous

The problems of quasi-static poroelasticity for stationary and extending cracks in an isotropic homogeneous medium are considered. The crack driving forces are caused by pressure of fluid injected inside the crack by external sources. Using simple and double layer potentials of poroelasticity, the problems are reduced to systems of 2D-integral equations on the crack surface. The integral equations

Aim of this work is to model a multiphasic porous material modified with a hydrogel made from a granulate of Superabsorbent Polymers (SAP). The void space of the material is simultaneously filled with two interacting phases, namely a chemically active hydrogel and a multi-component aqueous pore fluid. The hydrogel has the ability to absorb and retain large amounts of the pore fluid. Depending on the

Transverse wrinkles commonly occur in a uniaxially tensile elastic membrane and can vanish upon excess stretching. The wrinkling direction is usually perpendicular to the stretching direction under isotropic elasticity. Here, we show that wrinkles are orientable by material anisotropy, such as in fiber-reinforced or fibrous films, and the wrinkling orientation can be tuned by varying the stiffness

This paper is devoted to mathematical modelling of thermal processes in the polyp-colon system during electrosurgical polypectomy. This medical surgery (colonoscopy) is used to remove abnormal growths from the colon (the large intestine) in order to reduce the risk of the colon cancer development.In the electrosurgical polypectomy procedure, a polypectomy snare is passed over the polyp and tightened

Based on the variational three-point correlation results for the conductivity (thermal, electrical,...) of the multi-coated sphere assemblages, limiting procedures have been developed to construct the explicit expressions of the macroscopic conductivity and the respective microscopic gradient and flux fields for spherically-symmetric inclusion composites with anisotropic coating in d dimensions (d=2

In this review, we discuss replacement (or substitution) relations that quantify changes in various physical properties of heterogeneous materials, produced by variation in the properties of one (or several) of the constituents while keeping the microstructure unmodified. The latter may be formed by interconnected pores, isolated inhomogeneities (cracks, pores, inclusions), or represent the combination

We investigate theoretically the effects of capillarity and gravity on interfacial Marangoni waves (M-waves). Previous studies which neglected these effects have shown the decay rate of M-waves to vary monotonically. In this work, we disprove it by deriving a new dispersion relation (accounting for these effects) for the M-waves, and show that their decay rate passes through a minimum, rather than

An AFM-based nanoindentation of a spherical particle absorbed on a corrugated surface of rigid substrate is considered in the framework of continuum mechanics. The corresponding problem of unilateral frictionless contact with multiple contact zones is formulated using isotropic infinitesimal elasticity. Both the AFM probe surface and the surfaces of rigid supports, which are exposed to contact with

Classical elasticity mechanics fails to explain size-dependent phenomenon, the strain gradient elasticity theories including the couple stress theory, the simplified strain gradient elasticity theory and the general strain gradient elasticity theory are used to describe size effects. In this paper, the relations among the couple stress theory, the simplified strain gradient elasticity theory and the

Seismic surface wave mitigation using metamaterials is a growing research field propelled by intrinsic theoretical value and possible application prospects. Up to date, the complexity of site conditions found in engineering practice, which can include layered stratigraphy and variable water table level, has been discarded in the development of analytical frameworks to favor the derivation of simple

In this paper, we model breathing at the level of a human alveolus by developing a novel mathematical framework that links pulmonary mechanics and gas exchange. Unlike previous models, the developed alveolar model comprises the alveolar gas mixture, capillaries perfused in the alveolar wall, pulmonary surfactant lining the alveolus and the pleural cavity. The inclusion of the multiple compartments

Profound investigation of the unsurpassed mechanical properties of suspended graphene motivates the link between classical continuum mechanics (where the notions of “mechanical strength”, “mechanical stiffness”, and “elastic energy” have actually been coined) and density functional theory (DFT) rooted in quantum mechanics. Namely, the latter quantifies the energetic ground states of systems consisting

Atherosclerosis is the most common cardiovascular disease (CVD) causing increased morbidity. Although atherosclerosis is a general disease involving several factors, it preferentially affects the wall of the vessel bifurcations. The use of advanced Computational Fluid Dynamics (CFD) techniques has the potential to shed more light in the further understanding of the causes of the disease and perhaps

We investigate a recently proposed model of second-sound at the nanoscale—One that goes beyond the usual Maxwell–Catteneo theory of hyperbolic heat transfer. The model in question is based on a dynamical non-equilibrium temperature, denoted herein by β, that takes into account the effects of relaxation and nonlocality, both of which play an important role in heat-transport phenomena at the nanoscale

The effective (homogenized) stiffnesses of the corrugated plate are calculated by solving the periodicity cell boundary-value problems (BVPs) of homogenization theory using a two-step dimension reduction procedure. The three-dimensional (3-D) periodicity cell BVPs first are reduced to two-dimensional (2-D) problems in the plate cross-sections. Then, provided that the plate is thin, the 2-D elasticity

Understanding immiscible-phase fluid displacement in non-homogeneous pore structures is crucial to enhance resource recovery in the secondary development of old petroleum reservoirs. Reducing residual oil resources requires quantifying the effects of pore characteristics on the development of preferential displacement paths in porous reservoirs, which can be used to predict the preferential path of

A realistic/comprehensive biomechanical model of right/left coronary arteries is developed using the in vivo geometric and haemodynamic properties obtained from optical coherence tomography (OCT), angiography, and electrocardiography (ECG). The developed biomechanical model is constructed with the help of an image processing technique and simulated via the finite element method (FEM) for determination

We provide a derivation of several classes of boundary conditions for fluids of Korteweg-type using a simple and transparent thermodynamic approach that automatically guarantees that the derived boundary conditions are compatible with the second law of thermodynamics. The starting assumption of our approach is to describe the boundary of the domain as the membrane separating two different continua

As a first endeavor, the dynamic analysis of functionally graded graphene nanoplatelets reinforced composite (FG-GNPRC) cylindrical nanoshell subjected to a moving harmonic load is investigated. The effective mechanical properties of the nanocomposite are found using the Halpin-Tsai model and a modified rule of mixture. The equations of motion for the structure resting on an elastic foundation are

The representative unit cell (RUC) model of elastic heterogeneous solid with imperfectly bonded ellipsoidal inhomogeneities is developed. The periodic displacement solution has been obtained by combining the superposition principle, Papkovich-Neuber representation of displacement in terms of scalar harmonic potentials and expansion of these potentials in terms of periodic ellipsoidal harmonics. By

A consistent variational theory of the higher–order nonlocal gradient elasticity is conceived to appropriately introduce the nonlocality to the higher-order strain gradient theory. The abstract variational approach, based on appropriate functional spaces of test fields, is applied to establish the higher–order nonlocal gradient mechanics of elastic beams in flexure. Two nonlocal and two gradient characteristic

The size-dependent buckling instability of shear deformable nanobeams rested on a two-parameter elastic foundation is studied through the stress-driven nonlocal theory of elasticity and the kinematic assumptions of the Timoshenko beam theory. The small-scale size effects are taken into account by nonlocal constitutive relationships, which define the strains at each point as integral convolutions in

Long bones are composite materials possessing nonhomogeneous and anisotropic properties. They repair themselves (self-repairing) and adapt to changing mechanical demands by altering their shape and mechanical properties (self-adapting). Such exceptional features make long bones intriguing materials to comprehend properly. This also expands our knowledge of engineering materials and motivates researchers

A semi-analytical approach is proposed to determine the effective magneto-electro-elastic moduli of a fiber-reinforced composite. We especially focus on predicting the effective properties of three-phase periodic composite reinforced with unidirectional, infinitely long and concentric cylindrical fibers with square transversal distribution. The semi-analytical method is developed combining asymptotic

This work aims at proposing a general framework based on an intrinsic tensor formalism to relate Hill polarization tensors of elastic problems associated by a linear transformation without detailing the resolution of the problems. Such an approach somehow casts a new light on the calculation of some Hill tensors already known in the literature by means of other methods or other presentations. In particular

Frictional sliding occurs in many engineering and natural systems across the scales. Often observed stick slip (jerking) movement is commonly believed to be a consequence of friction rate dependence (static friction is higher than the kinetic one). Using a simple model of a frictionally sliding block connected to a spring we show that even for constant friction the intrinsic velocity oscillations produce

In this paper, a thermodynamically consistent interface stress is derived for the solid-gas interface of nanovoids within the concept of the phase field approach and using the laws of thermodynamics. The Cahn-Hilliard (CH) equation describes the evolution of nanovoid concentration which varies between 0 for perfect solid to 1 for gas. Considering the gradient term of the nanovoid concentration in the

The balance equations for micromorphic materials with mass flux and mass production are determined based on the phenomenon of self-diffusion. In this study, the self-diffusive flux is the flux of mass of a single micromorphic species within itself which is captured by defining the relative macro-element spatial velocity vector and the relative micro-gyration tensor. By use of a binary micromorphic

In this article, the dynamic behavior of functionally graded (FG) microbeams with different porosity distributions and acted by a moving harmonic load is studied. A bi-dimensional FG microbeam with its material properties changing gradually along both the length and thickness directions in a power-law distribution form is presented. Besides, the porosities are distributed evenly and unevenly in the