Two simple and fully analytical models are presented for a SMA bar or wire of circular cross section subjected to fully-reversed cyclic torsional loading, by taking into consideration the reorientation of the martensitic variants occurring during unloading and reverse loading. The process is assumed to take place at constant temperature between the start temperatures of the martensitic and austenitic

This work is concerned with the influence of non-smooth yield functions on material instabilities. The loss of ellipticity condition is examined in the case of a family of non-smooth yield functions in principal stress space. A procedure for the numerical detection of loss of ellipticity in multisurface plasticity is proposed. An explicit expression of the subdifferential of the non-smooth yield function

The thermal cyclic behavior of self-healing thermal barrier coatings (SH-TBC) is analyzed numerically to develop a lifetime prediction model. Representative microstructures are studied adopting a unit cell based multiscale modeling approach along with a simplified evolution model for the thermally-grown oxide layer (TGO) to study the evolution of damage and healing in a self-healing TBC system. The

A structural geometric nonlinear analysis using the finite element method (FEM) depends on the consideration of five aspects: the interpolation (shape) functions, the bending theory, the kinematic description, the strain–displacement relations, and the nonlinear solution scheme. As the FEM provides a numerical solution, the structure discretization has a great influence on the analysis response. However

Several medical papers have reported delamination of the coating from the stent-substrate following intravascular deployment leading to adverse outcomes for patients. However, the mechanisms of delamination of such polymer coatings from the surface of a stent due to large deformations during device deployment have not been studied. In this paper, a novel and in-depth investigation of the mechanisms

The reliable parameter identification method of the constitutive behavior under large strain conditions is essential for accurate simulation in the hot stamping and warm-cutting process. In this paper, the linear stress-strain curve identification (LSSCI) method is extended to identify the viscoplastic behavior of boron steel at large strain based on the full-field measurements in the Gleeble system

An improved mathematical model for the first lithiation of crystalline silicon is presented in the finite deformation framework. The crystalline-amorphous silicon interface kinetics is modelled through an addition reaction while the lithiation in the growing amorphous zone is captured through a reaction-diffusion model, incorporating a reversible alloying-dealloying reaction (ADR). The entire lithium

The representative directions method is a continuum mechanical based practical approach to transfer 1D material models to 3D. The selection of the directional energy and the corresponding directional stress is generally based on the standard uniaxial tension (UT) solution of hyperelastic models. However, this approach results in a somewhat different model than hyperelastic models in the context of

In order to investigate the behavior of elastoplastic composites exhibiting both isotropic and nonlinear kinematic hardening, we extend the Double Incremental Variational (DIV) formulation of Lucchetta et al. (2019), based on both the incremental variational principles introduced by Lahellec and Suquet (2007) and the formulation proposed by Agoras et al. (2016). However, the Armstrong-Frederick model

This paper studies the effective moduli of multiferroic fibrous composites with strain gradient and electromagnetic field gradient effects subjected to generalized anti-plane shear deformation. Using the energy variational formulation and the generalized self-consistent method, we can determine the effective moduli of the heterogeneous material. The derived solutions are then applied to a BaTiO3–CoFe2O4

Fiber reinforced materials consisting of aligned fibers within a matrix are effective for applications in nature and engineering in which strength and stiffness are required in a dominant direction. The fibers are typically coated. Optimization of these materials is typically based upon choosing elastic properties of phases to reduce static stresses. However, materials with well-matched moduli can

Generalized continuum mechanical theories such as second gradient elasticity can consider size and localization effects, which motivates their use for multiscale modeling of periodic lattice structures and metamaterials. For this purpose, a numerical homogenization method for computing the effective second gradient constitutive models of cubic lattice metamaterials in the infinitesimal deformation

Acoustic black holes (ABHs) achieved by thinning structural thickness following a power-law profile have shown fantastic applications in vibration and noise suppression, energy harvesting, and wave manipulation. For the latter, many passband properties exemplified by self-collimation, focusing, and bi-refraction, have been reported on metamaterial plates with embedded circular ABHs in periodic arrangement

This paper is devoted to the standard theory of gradient plasticity and visco-plasticity, cf. Gudmundson (2004), Fleck and Willis (2009) and the quoted references. Wihin the framework of the generalized standard materials and the generalized principle of virtual work, our attention is focussed on the mathematical basis of the theory in order to underline the basic assumptions, general results and principal

This paper presents a general method to estimate the first and second moments of the stress and deformation fields in linearized elastic and viscous composites and polycrystals. The methodology can be seamlessly extended by means of the ‘linear comparison’ variational homogenization methods (Ponte Castañeda, 1991, 2016) to extract the corresponding field statistics in composites and polycrystals with

A discrete Lagrangian approach is the basis for modelling the macroscale elastic response of a solid material, which can be homogeneous as well as a periodic composite. The basic topology is a square “heuristic molecule” that is an assemblage of four rigid bodies with a definite shape bonded by elastic springs. This is the minimum unit cell, UC, that contains all the macroscopic mechanical properties

Currently, the analytical analysis cannot describe the deformation and draping behavior in the hemisphere preforming for the plain woven fabric, especially considering the fabric deformation outside the hemisphere and the effect of the configuration parameters. Thus, an analytical analysis was established to characterize the sliding and shearing in the typical hemisphere preforming for the plain woven

In engineering stretchable electronics, an intermediate layer between a thin stiff film and a substrate can enhance the adhesion of the film and modulate its buckling shape. Capturing buckling behaviour of the tri-layer film/intermediate layer/substrate structure is essential for designing stretchable electronics. In this paper, considering the shear stress between the film and intermediate layer and

In the last decade, electrochemical strain microscopy (ESM) has emerged as a powerful tool to study electrochemical processes at the nanoscale, yet its quantitative analysis is quite challenging, involving complex electrochemo-mechanical coupling under highly concentrated electromechanical fields. In this work, we develop a theoretical framework of thermodynamics and kinetics for mobile ions in el

Based on the variational principle, we derive the balance equation for momentum, Maxwell equation, and the equation of director fields for nonlinear electro-opto-mechanical coupling in dielectric liquid crystal elastomers (LCEs). Further, we establish a simple constitutive model to study the electric-field-induced director reorientation with the deformation of monodomain nematic LCEs, which is called

Transfer printing is an emerging technique for deterministic assembly and integration of multiscale and classes of materials on desired substrates with great potential in developing advanced electronic systems. Theoretical mechanics models are developed for an active elastomeric adhesive with the focus on the unusual capabilities of non-contact pick-up and printing. The active adhesive features cavities

Postbuckling of inextensible rings made from chiral filaments with intrinsic twist is studied. We show that the critical amount of intrinsic twist at which chiral elastic rings buckle might be greater than that at which buckling would occur with no chirality, dependent on degree of chirality and twist-to-bend ratio. Moreover, increasing the twisting rigidity relative to the bending rigidity of the

A cluster interaction model has been proposed to account for the spatial distribution and morphology of particles when estimating the effective properties of elastic and thermoelastic composites (Molinari & El Mouden, 1996). In the present paper this approach is extended to elastic-viscoplastic composites. To this end the tangent linearization of the non-linear viscoplastic law and the concept of additive

This work extends the recently developed surface poromechanics theory to explain the unusual contraction behaviour of some microporous materials at the early stage of adsorption. In micropores, the overlap of adsorbed layers near opposing solid walls can give rise to forces that are formerly disregarded in the analysis of macro/meso porous materials. The effect of these interactions is studied at the

This article provides the mathematical solutions to the elastodynamic fields of a semi-infinite interface lying along two dissimilar media subjected to sudden loading. The article offers the solution to the cases when: (1) the interface slips, i.e., it cannot transfer shear stress from one material to the other, which represents a Hertzian contact; (2) the interface is welded, i.e., all stress components

We investigate the propagation and arrest of a radial hydraulic fracture upon the end of the injection. Depending on the regime of propagation at the time of shut-in of the injection, excess elastic energy may be stored in the surrounding medium. Once the injection has stopped, the hydraulic fracture will arrest when the energy release rate falls under the material fracture energy. Fluid leaking-off

In this study, we follow the work of Tvergaard and Needleman (1995, 1997) and Needleman and Tvergaard (1998) and present the numerical implementation and initial applications of a non-local Gurson-Tvergaard-Needleman (GTN) model for explicit finite element (FE) analysis. The delocalization relates to the damage mechanism and is incorporated in terms of an integral condition on the rate of change of

The occurrence of buckling during cooling of an injection-molded fiber-reinforced plastic (FRP) object is a complex phenomenon which can result in unacceptably large deformations. The present work focuses on the thermal buckling of injection-molded thin disks, as they are representative for the local behavior in parts of a more complex object. An analytical approach based on the Föppl-von Kármán theory

A computational model for analysis of interface damage is introduced. It provides results for initiation and growth of cracks along a damaged interface in a multi-domain structure which is considered to be exposed to a periodically repeating load. First, the simulation of damage processes takes into account various possible relations between interface stresses and domain deformation leading to separation

Image processing techniques like X-ray microtomography are nowadays extensively applied to reveal micro mechanisms behind macroscopic response of various media and also to reconstruct material microstructure for refined modelling and simulation of diverse properties. For the latter, robust numerical methods making direct use of material and microstructural information at voxels (material grids) and

The present work sheds light on the stresses generated in a spherical particle subjected to phase transformations during ion-insertion. In order to account for the physical process that occur during electrochemical cycling, the models used are those of small deformation and account for the effects of phase transformation, chemo-mechanical coupling and concentration-dependent material properties. The

Stimulus responsive elastomers are advanced engineered materials that perform desired functionalities when triggered by external stimuli. Liquid crystal elastomers (LCEs) are one important example that exhibit reversible actuation when cycled above and below their nematic-to-isotropic transition temperature. Here, we propose a micromechanical-based model that is centered on the evolution of the chain

In its original formulation by Forest & Sab (Math. Mech. Solids, 2017), stress gradient elastodynamics incorporate two inner-lengths to account for size effects in continuum theory. Here, an extended one-dimensional stress gradient model is developed by means of Lagrangian formalism, incorporating an additional inner-length and a fourth-order space derivative in the wave equation. Dispersive properties

The fracture behavior in stiff-thin-film-on-soft-substrate structures (STFSS) differs significantly from that in bulk materials, and has thus become a hot spot in solid mechanics and materials. Traditional research on the fracture mechanics in STFSS mostly focuses on the mechanical behavior under uniaxial stress state. However, in actual applications, STFSS is subjected to biaxial loading. In response

The fracture behavior of adhesively bonded joints is of interest in a variety of industrial, natural and biological applications. This effort re-examines literature data with an emphasis on thin bonds and their relation to delamination resistance. Brittle, ductile and particulate epoxy adhesives were considered with the bond thickness t varying from 1 to 1000 μm. The results shed new light on some

This study deals with the impact of cylindrical eigenstrains on the traveling wave solutions of a neo-Hookean cylindrical rod. For this purpose, we consider an isotropic, incompressible neo-Hookean rod with the symmetrical distribution of radial, circumferential and longitudinal eigenstrains. To establish the momentum balance equations, we construct a Riemannian manifold as the reference configuration

We investigate localised bulging or necking in an incompressible, hyperelastic cylindrical tube under axial stretching and surface tension. Three cases are considered in which the tube is subjected to different constraints. In case 1 the inner and outer surfaces are traction-free and under surface tension, whilst in cases 2 and 3 the inner and outer surfaces (respectively) are fixed to prevent radial

Paper is a complex material consisting of a network of cellulose _bres at the micro-level. During manufacturing, the network is dried under restraint conditions due to tension in the paper web in machine direction. This gives rise to internal strains that are stored in the produced sheet. Upon exposure to a moisture cycle, these strains may be released. This results in permanent shrinkage that may

Bolted joints are often used for the connection of safety-critical parts in the aeronautical industry. However, drilling holes also means introducing stress concentrations and precise assessment tools are essential to design both safe and lightweight optimal structures. These tools can be based on analytical means providing efficient computation. That is why the present work is dedicated to determine

Cable domes are cable-strut structural systems widely used as large span roofs of arenas, stadiums, and open spaces for their lightweight forms and aesthetic impact. We first recall the matrix theory for the static and kinematic analysis of pin-jointed cable-strut structural assemblies. This theory is used to identify potential states of self-equilibrated prestress for a given structure, and to evaluate

A micromorphic formulation of the phase-field model of martensitic transformation is developed within the incremental energy minimization framework. In contrast to the conventional phase-field formulation, the order parameters are viewed as local variables and the corresponding evolution equations are solved at the material-point level, i.e. at the Gauss points in the finite-element setting. From a

In this work, we have explored growth-induced mechanical instability in an isotropic circular hyperelastic plate. Consistent two-dimensional governing equations for a plate under a general finite strain are derived using a variational approach. The derived plate equations are solved using the compound matrix method for two cases of axisymmetric growth conditions { purely radial, and combined radial

Cracks have a major influence on the service life of brittle porous materials like concrete. Especially, the hydraulic properties within the cracked area are significantly changed compared to the uncracked material. Former research often focused exclusively on the prediction of the initiation and growth of cracks or on the moisture transport, while the coupling between the moisture transport and the

Existing theoretical methods for solving the stress intensity factors (SIFs) of a cracked V-notch plane are products of highly sophisticated mathematical analyses and are therefore, challenging for engineers to study, derive, and reproduce. Based on our extension of the dimensional analysis, or the 'geometry parameter method', we investigated a V-notched edge of a semi-infinite plate with a crack at

Subsequent yield surfaces of ductile solids, pre-strained in shear and/or tension, exhibit various characteristic features that depend on the proof strain used to detect yield. These features include kinematic hardening when the proof strain denoting yield is low, isotropic hardening when it is high, formation of a ‘nose’ in the loading direction and flattening of the rear part of the yield surface

Chip peeling-off, mainly accomplished through the cooperation of needle-ejecting and vacuum-absorbing, plays a critical role in chip transferring process. However, there are few studies involving the quantification of process parameters, such as optimal needle position, needle force or displacement, to access to a reliable chip peeling. In this paper, optimization criteria for a high success rate of

In the automotive industry, crack prediction is an important step of the design: its accuracy is crucial to avoid additional development costs and delays. However, its simulation is not always reliable yet which could be explained by the use of too simple fracture criteria. A possible solution could be the improvement of the fracture behavior prediction through the use of coupled damage models. Unlike

The current study investigates the non-coaxial plastic flow in granular media where the principal directions of incremental plastic strain differ from those of the current stress (and of the current fabric tensor). The stress probing technique is used with Discrete Element Method simulations to capture the plastic response of a 2D granular assembly to loading increments along different directions in

Ferroelectric polymers have attracted increasing attention due to their distinguished dielectric and piezoelectric properties. Dielectric breakdown is one of the main failure behaviors for ferroelectric polymers. Understanding dielectric breakdown of ferroelectric polymers under mechanical and electrical loadings is crucial to their applications in energy storage and conversion devices with high-energy-density

The present work addresses two key issues relating to the study of rate effects in adhesively bonded joints. Firstly, the accurate determination of the crack tip strain rate and secondly the accurate determination of cohesive zone length. The rate-dependent fracture behaviour of adhesive joints bonded with either a toughened epoxy or a ductile polyurethane adhesive was investigated under mode I loading

A multi-scale method based on a combination of the boundary element method (BEM) and peridynamics (PD) was developed to model crack propagation problems in two-dimensional (2D) elastic bodies. The special feature of this method is that it can take full advantage of both the BEM and PD to achieve a higher level of computational efficiency. Based on the scale of the structure and the crack location,

High density polyethylene (HDPE) is increasingly used in infrastructure applications with a design service lifetime of several decades. In many cases, the HDPE member is exposed to a corrosive environment, such as in pipes carrying potable water, where the dissolved bleach selectively attacks the loosely packed amorphous phase of the polymer. The failure mechanism of HDPE transitions from a ductile

A two-order asymptotic solution for sharp V-notch tip mechanics field in elasto-viscoplastic solids with power-law form under mode I loading is developed. The stress exponents and angular distributions for various notch angles and viscoplastic exponents for the second terms are reported. The stress exponent of the first order is singular and is non-singular except for low creep exponent with small

It is known that a local deformation mode affects the fracture behavior. First, a parameter that represents the deformation mode is defined for a fracture criterion that can consider the deformation mode in ordinary state-based peridynamics. This parameter is analogous to stress triaxiality in conventional continuum mechanics. The calculated values of the parameter agree well with the theoretical values