In this study, the electrokinetic energy conversion efficiency is investigated theoretically in high pressure-driven flow with the pressure-viscosity effect. Calculations of the electrokinetic flow in a straight nanochannel are based on the Poisson-Boltzmann equation and modified fluid momentum equation. Once the viscosity of fluid is dependent on the pressure, the strongly non-linear governing equation

We use the theory developed by [43] to simulate in Abaqus the printing of a drug-eluting bioresorbable stent (BRS), which is used to treat a stenosed renal artery, by fused deposition modeling (FDM). The stent is assumed to be printed using a semi-crystalline polylactic acid (PLA). We control the process parameters to architect the microstructure of the stent such that the stent has an amorphous glassy

Aortic dissection is a major aortic catastrophe with a high morbidity and mortality risk, and thoracic endovascular repair (TEVAR) has recently been established as the preferred treatment option for promoting false lumen (FL) remodeling and improving hemodynamics in the true lumen. Complete thrombosis of the FL has been thought to be a prerequisite for healing of the aorta postdissection, whereas flow

We consider the anti-plane shear waves in a domain consisting of an infinite layer with a thin coating lying on an elastic half-space. The elastic properties of the coating, layer, and half-space are assumed to be different. On the free upper surface we assume the compatibility condition within the Gurtin–Murdoch surface elasticity, whereas at the plane interface we consider perfect contact. For this

Abstract not available

For a relatively new class of constitutive equation for incompressible elastic bodies, wherein the Hencky strain tensor is a function of the Cauchy stress tensor, incremental equations are obtained, where it is assumed the presence of an initial time-independent stress that causes large deformations, to which a small time-dependent stress tensor is added. That stress tensor is assumed to cause a small

A rigorous, comprehensive, and thermodynamically consistent theory has been developed for the fused deposition modelling (FDM) of semi-crystalline polymers. It is sufficiently general in that it can accommodate multiple phase transition mechanisms (crystallization, glass transition, and melting) during the heating and cooling cycles of the process encountered during FDM. The theory predicts the residual

Examples are presented when propagation of the boundaries of the zones of frictional sliding or elastic shear propagate with the speed of the longitudinal wave (or p-wave) and thus can be confused with the instances of intersonic fracture propagation. In these examples the mechanism of intersonic sliding/shear zone propagation is the longitudinal elastic deformation of the material surrounding the

In a previous paper, the last author proposed with Buliga a symplectic version of Brezis–Ekeland–Nayroles principle based on the concepts of Hamiltonian inclusions and symplectic polar functions. It was illustrated by application to the standard plasticity in small deformations. The objective of this work is to generalize the previous formalism to dissipative media in finite strains. This aim is reached

The elastic fields, surface constants and effective elastic moduli of nanoparticles are studied by means of classical molecular dynamics and continuum mechanics. Two analytical models of isotropic nanoparticles are considered. The first model is a sphere coated with a thin surface layer, which simulates the effect of the free surface energy in the nanoparticle. In the second model, the surface effect

A long-standing area of research for computational shock physics has been the treatment of mixed materials. A mixed material volume is defined as a control volume space where two or more materials coexist as immiscible materials having separate densities and energies that have non-equilibrium stress and thermal states. In traditional computational shock physics framework, a mixture of materials can

This work analyses the stochastic response of fibre and matrix scale stresses of Variable Angle Tow (VAT) laminates affected by multiscale uncertainty defects. The aim is to evaluate the influence of the innermost constituents on the overall structural response via an accurate mechanical characterization of both macro- and microscales. The Carrera Unified Formulation (CUF) is employed to obtain two-dimensional

Recently, hard-magnetic microparticles were embedded into soft matrix to manufacture a new type of magnetoactive soft materials, i.e. hard-magnetic soft (HMS) materials. Due to the promising applications of HMS materials in the areas of soft robotics, flexible electronics, biomedicine, etc., there is a burgeoning trend in investigating the mechanical responses of HMS structures. Special attention has

This paper applies a semi-analytical polynomial method (SAPM) to solve the mechanical governing equations of nonlinear static and dynamic deformations, free and forced vibrations, and buckling analyses of nano-sized spherical functionally graded structures. Due to the nano-sized structure, the constitutive equations of motion are obtained based on the nonlocal elasticity theory. The governing equations

Abstract not available

A new approach to the mechanical response of micro-mechanic problems is presented using the modified couple stress theory. This model captured micro-turns due to micro-particles' rotations which could be essential for microstructural materials and/or at small scales. In a micro media based on the small rotations, sub-particles can also turn except the whole domain rotation. However, this framework

This work develops a model and rapid simulation strategy for the electrically-driven dissociation (unlocking) of subsurface gas hydrates. There are two schools of thought, as to how electrical fields can dissociate gas hydrates: Case 1: gas hydrates are dissociated (unlocked) by an appropriate intensity and frequency of the electric field, Case 2: gas hydrates are dissociated by an appropriate level

In this paper, the cohesive fracture is revisited as an energy minimization problem. The energy functional is rigorously derived based on a pair of integral transformations and a novel directional energy decomposition method. The resulting description of the regularized crack is perfectly suitable for cohesive fracture. A well-defined crack direction is associated with each material point. The resulting

The problem of reconstruction and quantitative characterization of the microstructure of random composites, as a fundamental problem of material sciences, has been a subject of a considerable amount of literature. Thus far, previous studies used for the reconstruction either statistical microstructure descriptors or the overall property of real material. This paper makes a major contribution to research

The stress gradient, strain gradient, and classical elasticity theory are integrated within a consistent variational framework to conceive the mixture unified gradient theory of elasticity. The significant advantage of the established stationary variational principle lies in incorporating all the governing equations, viz. the boundary-value problem of the associated dynamic equilibrium along with the

In this work, a unified high-order nanobeam model considering various high-order shear deformation beam theories is established to investigate the vibration response of nanobeam on the basis of two-phase local/nonlocal strain and stress gradient theory, as well as surface elasticity theory. The unified model also includes the Euler-Bernoulli beam model and Timoshenko beam model. Herein, the elastic

The paper is devoted to simulation of the effective elastic properties of rock materials containing two substantially different types of defects simultaneously: random sets of ellipsoidal pores (cavities) and elliptical cracks. For solution of the homogenization problem and calculation of the effective elastic properties of such materials, the self-consistent effective field method is used. For composites

We present a continuum theory for analyzing the interaction between the thermoelectric and mechanical fields in piezoelectric semiconductors. The balance laws and dissipation inequality are formulated in the reference configuration. Thermodynamically consistent constitutive equations are derived, including the drift-diffusion current, Fourier's law for thermal flux, Seebeck effect, and Peltier effect

Elastic wave propagation in porous media containing a movable fluid is frequently accompanied by electromagnetic field generation. Such field can be produced, for instance, by piezoelectric effect or have electrokinetic origin. In the present work, we consider the case of electrolyte-filled pores; thus, the generated electromagnetic field is associated with the electrokinetic effects. In this case

The main target of this paper is to evaluate the geometrically nonlinear and size-dependent response of shallow sandwich curved micro-panels (SCMPs). In this regard, the governing equations are developed by using modified couple stress theory (MCST) based on the first-order shear deformation theory (FSDT). The proposed sandwich micro panels are assumed to be made of three layers so that the middle

Flexoelectricity – the effect where inhomogeneous polarization causes deformation – substitutes symmetry-forbidden piezoelectricity in nano-scale centrosymmetric materials. Its mathematical treatment in terms of continuum mechanics represents a challenge: correct models are subjects of debates during the past decades. In the present article we formulate a model with reasonable approximations for converse

This paper focuses on the modeling of the effect of different porosity on the overall elastic properties of saturated cortical bone and ultrasound wave propagation in such bone. We first utilize micromechanical model of Zhou, Cui and Sevostianov (2020) to model anisotropic effective elastic stiffness of saturated cortical bone and evaluate the effect of partial porosities. It is shown that the moduli

Abstract not available

A general and unified theory is formulated to investigate static and time-harmonic field solutions induced by dislocation loops and dislocation arrays in three-dimensional multilayered structures. Each homogeneous plate consists of an orthotropic magneto-electro-elastic material including nonlocal effects. While the nonlocal constitutive relations with multi-phase coupling are treated by means of the

Elastic metamaterial, an engineered artificial material, has received much attention in physics and engineering communities due to its functional properties unavailable in natural materials. However, most elastic metamaterials, especially for their two-dimensional structures, belong to the Hermitian category, making them difficult to adapt to real lossy structures and explore their loss modulation

The study of elastic wave propagation in poroelastic media is of considerable scientific interest because of some effects that do not appear in monophasic elastic or viscoelastic media. In the case of interconnected pores containing a moving fluid in a poroelastic medium, there exist two types of longitudinal waves. In heterogeneous porous media, the energy of elastic oscillations is redistributed

This paper describes a newly proposed viscoelastic–viscoplastic constitutive model that is used to characterize the effective mechanical behaviors of fiber-reinforced composites based on micromechanical modeling. A homogenization approach is developed in which the effective stress of the fiber-reinforced composite is decomposed into an elastoplastic component and a viscous component. For the elastoplastic

In many actual technological problems the system response is dictated by multi-physics events, which occur at different space–time-scales. Energy storage systems or active polymers are two illustrative real-life applications: they involve diffusion of chemically active species concurrent to mechanical deformations that take place in the same spatial domain. An abundant literature exists nowadays for

Abstract not available

A plethora of current applicative problems of Nano-Engineering involve nanostructures interacting with elastic media which exhibit significant size effects. Internal elasticity of the nanostructure and external elasticity of the surrounding foundation can be conveniently modelled by two nonlocal continua, provided that the relevant structure-soil problem results to be well-posed. This issue is still

The objective of this study is to understand the formation of vortices and other flow characteristics associated with the three-dimensional motions of an incompressible Navier–Stokes fluid in tubes containing a sinusoidal extension. The study has some bearing on two conjectures that da Vinci made concerning the flow of blood through the aortic root. We investigate how the flow attributes change with

Two different families of planar exact solutions for second grade fluid flows are derived in this paper. Exact solutions for Newtonian fluid flows are derived as particular case when normal stress moduli vanish. The novelty of the solutions is that they are obtained by assuming the stream functions as a finite sum of functions with different arguments. An important property of the derived solutions

The stress-driven nonlocal continuum theory is a well-established integral elasticity formulation. Modelling the elastic strain via a convolution integral between stress and an averaging kernel, the theory leads to an integro-differential structural problem for arbitrary 3D nonlocal solids. Integral elasticity solutions are mainly available for 1D solids by adopting a bi-exponential kernel and reverting

The distribution of the temperature and heat flux fields around a couple of unequal nonconductive tangent spherical inhomogeneities (or pores) embedded in an infinite medium under a steady-state and remotely applied heat flux is addressed in the present work. Owing to the 3D geometrical layout of the inhomogeneity, use is made of the tangent sphere coordinate system. A corrective temperature field

Longitudinal elastic stress wave propagation through a 180° bend junction connecting two square bars is analyzed using analytical and numerical approaches and validated against experiments. The aim is to identify conditions under which the one-dimensional stress propagation principles can be applied to this geometry despite complete reversal of the stress wave path and study the mechanism of wave propagation

Abstract not available

We revisit the sharp-interface continuum thermodynamics of two-phase multicomponent fluid systems with interfacial mass. Since the published work is not fully consistent, we provide a rigorous derivation of the local balance equations and the entropy production rates, including all relevant steps and mathematical tools. Special emphasis is put on an axiomatic form of the entropy principle which, at

Classical viscous fingering patterns in flow displacement can be modulated by incorporating polymers into either of the two fluids. The polymeric solutions are viscoelastic fluids exhibiting both shear-thinning as well as elastic behavior. The present numerical study examines the dynamics of viscous fingering in miscible flow displacement with either displacing or displaced fluid being treated as polymeric

Phase field theory for fracture is developed at large strains with an emphasis on a correct introduction of surface stresses at nanoscale. This is achieved by multiplying the cohesion and gradient energies by the local ratio of the crack surface areas in the deformed and undeformed configurations and with the gradient energy in terms of the gradient of the order parameter in the reference configuration

It is a long-standing challenge to predict the thermo-mechanically coupled behaviors of initially stressed soft elastomers since most of the existing theories ignore the influences of thermoelastic deformation histories. The constitutive equations may be completely different even for the same initial stresses, if the latter is originated from isothermal and adiabatic deformations, respectively. In

The paper presents a novel approach for analysis of thermoelasticity problems for solids with deformable thread-like (wired, textile) inhomogeneities. It is proposed to model a thread-like inclusion with a spatial curve, with appropriate influence functions set on it. The mathematical models of heat conduction and thermoelasticity of thread-like inclusions are obtained, which account for thermal, elastic

This work is promoted to analyze the time-dependent behavior of composite panels. Furthermore, different curves and boundary conditions are also covered. The material properties for the composite panel are assumed to be vary continuously within z-direction. The effective material properties are estimated via Voigt’s micro-mechanical model by a modified-power law rule for arbitrary power index. The

In this paper we develop a three-dimensional constitutive model to describe the linear viscoelastic behavior of fluid-saturated porous solids. The proposed model is based on a representation of the solid free energy by equilibrium and non-equilibrium parts. Constitutive equations corresponding to a compressible solid matrix/phase and an incompressible solid matrix/phase are derived separately. For

The 3D dynamic equations in elasticity for a thin transversely inhomogeneous plate are subject to asymptotic analysis over the low-frequency range. The leading and first order approximations are derived. The former is given by a biharmonic equation on the mid-plane generalizing the classical Kirchhoff equation for plate bending. A simple explicit formula for the effective bending stiffness is presented

A nonlocal stress-driven model for geometrically nonlinear behavior of a shallow arch under radial pressure is presented. The analytical nonlinear equilibrium equation and also buckling equations by variational principles and virtual work are found. As it has been proven before, the strain-driven models encountered some contradictions with local equilibrium conditions, while stress-driven formulation

This paper presents the novel triply periodic minimal surface (TPMS) based photostrictive composite as an alternative to naturally occurring photostrictive materials. The non-thermal, light-induced mechanical strain i.e., photostriction involves the simultaneous action of photovoltaic effect and converse piezoelectric effect. All the effective elastic, dielectric, piezoelectric, and pyroelectric properties

The plane problem of multiple collinear cracks between two piezoelectric semi-infinite spaces is considered. The cracks can have arbitrary lengths and distances between each other and they are assumed to be electrically conductive. The materials are polarized in the orthogonal to the interface direction. In-plane combined tension-shear loading and the electric field parallel to the crack faces are

Abstract not available

The article focuses on non-uniqueness, bifurcation and stability conditions in elasto-viscoplastic boundary value problems when inertia terms are neglected. Analytical and numerical studies are presented to investigate the capability of an elasto-viscoplastic model to regularize the behavior in the occurrence of strain localization with respect to number of strain bands formed and mesh dependency.

Surgical replacement of the diseased aortic valve consists in the implantation of a prosthetic heart valve (PHV), either biological or mechanical (BHV and MHV, respectively). Risks of complication have been linked to high levels of turbulence and consequent energy dissipation induced by the PHV. As helicity is an emergent feature in cardiovascular flows, deemed to impact blood flow organization, stability

Recent experiments demonstrated that the macroscopic thermal expansion (TE) response of bulk shape memory alloys (SMAs) can be tailored via martensite variant texturing by taking advantage of the significant intrinsic TE anisotropy of the martensite lattice. Here, a description of the TE response of SMAs is proposed, which relies on the volume fraction of oriented (detwinned) martensite and the orientation

Two high order imperfect interface models of elastic spherical interphase are developed using the Bövik-Benveniste methodology. In one model, the effect of the layer is accounted for via jumps in the field variables across the traces of its boundaries, while in the other—via corresponding jumps across the trace of its mid-surface. The derived higher order jump conditions are incorporated into the unit

It is known that damage or inelastic softening can cause an ill-posed problem leading to localization and mesh-dependence in finite element simulations. In this paper, a nonlocal hardening variable, κ̄, is introduced in a finite deformation Eulerian formulation of inelasticity with a rate-independent smooth elastic–inelastic transition. This nonlocal variable is defined over an Eulerian region of nonlocality