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

A non-classical quasi three-dimensional shell theory is proposed to analyze the static phenomenon of doubly-curved nanoshells whose made of functionally graded (FG) anisotropic material. The mechanical properties vary exponentially via the z-axis. Compared to other shell theories, the proposed model needs only seven unknown variables to determine fourfold coupled (axial-shear-bending-stretching) static

We propose a simple analytical model to evaluate changes in the overall elastic properties of metal matrix composites during the manufacturing process. The problem is solved in several steps. First, the moving boundary problem on formation and growth of the transient layer between the matrix and inhomogeneities is solved analytically in quasi-stationary approximation. This solution is used to estimate

The main purpose of the paper is to present an extended analysis of the coupled system of linear equations describing wave propagation in fluid-saturated porous materials used for the determination of their fundamental characteristics. The present paper is the first part, mainly devoted to the analysis of the system of equations describing transverse wave propagation. The analysis of equations for

Tough pH-sensitive hydrogels with noncovalent bonds have been developed in recent years as a promising structural material. They are involved in many engineering devices and natural phenomena due to their attractive properties. In this paper, we develop an electro-chemo-mechanical theory for swelling and mechanical behavior of tough pH-sensitive hydrogels. Due to its large deformation and time-dependent

The underlying mechanisms of surface phenomena are very complex and still not entirely clear. The aim of this work attempts to reveal the important contribution of the nonlocal integral theory of elasticity to surface elasticity, which is of fundamental scientific interest. By considering a uniform and isotropic half-space medium subjected to an arbitrary uniform strain, it is shown that the bulk is

The main objective of this work is to estimate the compliance contribution tensor of the concave pore inhomogeneity surrounded by a transversely isotropic matrix. In this light, we make use of a recently developed adapted boundary conditions based Finite Elements Method to incorporate the matrix anisotropy and the correction of the bias induced by the bounded character of the mesh domain, which allows

An Eulerian form of thermodynamically consistent generalized thermoelastic model capable of accounting for thermal signals is proposed. The heat flux is assumed to consist of both energetic and dissipative components. The constitutive relations for the stress, entropy and the heat fluxes are derived in the spatial coordinate system. Later on, a domain of dependence inequality for the proposed hyperbolic

We consider an incompressible viscous fluid flowing through a cylindrical pipe with rough wall. Motivated by the applications, we assume the periodicity of the roughness in the longitudinal direction and that the flow is governed by the prescribed pressure drop between pipe’s ends. The goal of the paper is to investigate the effects of the corrugated boundary on the fluid flow by taking into account

Implicit constitutive relations are proposed for electro-elastic and thermo-electro-elastic solids, which cannot be classified as Cauchy or Green elastic bodies, i.e., where in general it is not assumed that the stresses and one of the electric variables are given as functions (or the derivative of an energy function) in terms of the strains, and the independent electric variable. Some subclasses of

Gibbs-Duhem equation is a fundamental relation of the thermodynamics of fluids that originates from the extensive behavior of fluids. Fluids adsorption in micro-porous media can break the extensivity with respect to volume, so that Gibbs-Duhem equation does not hold in general for adsorbed fluid. As a consequence, a total of 6 moduli are needed to fully describe the thermo-mechanics of an adsorbed

We examine the stability of a soft dielectric plate deformed by the coupled effects of a mechanical pre-stress applied on its lateral faces and an electric field applied through its thickness under charge control. The electric field is created by spraying charges on the major faces of the plate: although in practice this mode of actuation is harder to achieve than a voltage-driven deformation, here

The issue of applicability of the Morphologically Representative Pattern (MRP) approach to elastic-plastic composites is addressed. The extension to the regime of non-linear material behaviour is performed by employing the concept of incremental linearization of the material response in two basic variants: tangent and secant. The obtained predictions are evaluated through comparison with the outcomes

The Boussinesq problem, namely the indentation of a flat-ended cylindrical punch into a viscoelastic half-space is studied. We assume a linear viscoelastic model wherein the linearized strain is expressed as a function of the stress. However, this expression is not invertible, which makes the problem very interesting. Based on the Papkovich–Neuber representation in potential theory and using the Fourier–Bessel

The mechanical response of filled rubber depends on load history, strain rate and state, temperature and even direction of previous loading. Although there is a plurality of both physical and phenomenological models, only few are able to reproduce this rich spectrum of effects. Moreover, many of them suffer from physical or mathematical inconsistencies. We present a model, which is based on physical

Addressed in this article, as the first attempt, is the forced coupled nonlinear mechanics of functionally graded (FG) nanobeams subject to dynamic loads via developing a high-dimensional model. A geometric nonlinear Euler-Bernoulli theory is used to define the displacement distribution. To incorporate small-size influences a nonlocal strain gradient theory (NSGT) scheme, possessing two independent

In this paper, we consider the problem of the scattering of in-plane waves at an interface between a homogeneous medium and a metamaterial. The relevant eigenmodes in the two regions are calculated by solving a recently described non self-adjoint eigenvalue problem particularly suited to scattering studies. The method efficiently produces all propagating and evanescent modes consistent with the application

In this paper a problem of a hydraulic fracture driven by a non-Newtonian shear-thinning fluid is analysed. For the PKN fracture geometry three different rheological models of fluid are considered: (i) the Carreau fluid, (ii) the truncated power-law fluid, (iii) the power-law fluid. For each of these models a number of simulations are performed. The results are post-processed and compared with each

Conformability is a property of materials that allows them to conform to the contours of a curved or rough surface. The lack of conformability of a thin plastic film lying on a non-flat substrate is commonly manifested in formation of blisters, wrinkles and other forms of delamination. The delamination is driven by elastic energy of thin film associated with the film deformation required by film application

The solution to the generalized conduction Eshelby problem of a confocal N-layer spheroid with low or highly conducting interfaces between isotropic layers is provided thanks to a decomposition in series of harmonics. A generic workflow is detailed for practical numerical implementation including a fine analysis to assess the influence of the level of truncation of the infinite series. The case of

Permittivity is a widespread property used to estimate the water content in concrete. To improve the reverse conversion from permittivity measurements to moisture content, we suggest the building of an electromagnetic model of concrete. In this paper, such a model is developed for the case of cement pastes. It relies on electromagnetic homogenization schemes which require an information about the permittivity

The problem of an elastic shaft fitted into an under-sized hole in an elastically identical body, the latter in the form of a half-space, has been studied when the assembly is subject to increasing and then subsequently reducing torque. The solution has been found as the superposition of a unilateral solution for an adhered contact pair and a set of ring dislocations along the contact interface to

The yielding, plastic flow and fracture of age hardenable aluminium alloys depend on the quench rate to room temperature after the solution heat-treatment at elevated temperature and before the artificial ageing. We investigate three AlMgSi alloys with different grain structure and crystallographic texture experimentally to determine the effects of quench rate (either water-quenching or air-cooling)

The so-called smart structures are frequently inspired by the art of origami, and they are in many cases considered to be manufactured of smart materials such as shape memory materials. We propose a mathematical model for such origami-like structures made of light activated shape memory polymers, and we develop a reference code for computer simulations of such structures. The proposed mathematical

The linear stability of shear-imposed liquid film flow past an inclined plane is examined when a soft, deformable solid layer is attached to the inclined plane. A liquid film flowing past a rigid inclined plane exhibits a long-wave gas–liquid (GL) interfacial instability which is modified by the presence of an imposed shear stress at gas–liquid interface. This GL interfacial mode does not become unstable

It is widely accepted that the lattice transformation strain and plastic shearing of a martensite embryo preset its final lattice orientation. However, the phenomenological theory of martensite crystallography (PTMC) solves an inverse problem where accommodative slip or twinning systems leading to certain structures are sought among a lot of admitted candidates. This approach explaining the known result

Lattice materials are characterised by their equivalent elastic moduli for analysing mechanical properties of the microstructures. The values of the elastic moduli under static forcing condition are primarily dependent on the geometric properties of the constituent unit cell and the mechanical properties of the intrinsic material. Under a static forcing condition, the equivalent elastic moduli (such

This paper aims to determine the in plane effective elastic properties of two-dimensional (2D) materials containing nanovoids of arbitrary shape. To achieve this objective, the complex variable and the associated conformal mapping techniques are used to solve the heterogeneity problem of a single nanovoid with arbitrary shape embedded in an infinite matrix. In this particular problem, to capture the