In small-scale mechanical tests, such as micropillar compression tests, plastic deformation is often localized in narrow slip traces. These slip traces result from a few dislocation sources with relatively low nucleation stresses that are present in the material. In order to accurately simulate such small-scale experiments, the stochastics of the underlying dislocation network must be taken into account

Starting from the exact solution of the heterogeneous linear viscoelastic Eshelby ellipsoidal inclusion problem obtained in the time domain for an ellipsoidal inclusion embedded in an isotropic matrix (Berbenni et al., 2015), a direct time-incremental homogenization Mori-Tanaka scheme for two-phase non linear elasto-viscoplastic materials is proposed. The extension to non-linear behavior is based on

The aim of the article is mathematical modeling of behavior of hyper viscoelastic particulate reinforced composite materials. Three dimensional hyper viscoelastic constitutive equations, which include an inherent damage parameter and its functions, have been developed. The model was used to demonstrate physical phenomenon such as the so called dewetting effect. New strain rate, damage rate and stress

Corrugated structures are made up of panels with periodic profiles. These are used as a compliant mechanism and as core in sandwich plates for their direction dependent stiffness. Modeling and large deflection analysis of corrugated structure play an essential role in their design and application. This work proposes an iterative scheme for the large deflection analysis of double corrugated cantilever

Data on the room temperature behavior of titanium is limited. To assess the anisotropy of the plastic behavior of a commercially pure grade 2 hcp–titanium T40 for different strain paths, in this study both uniaxial tests in various orientations with respect to the rolling direction as well as bulging tests using different die apertures were conducted. Under uniaxial tension, the plastic anisotropy

Multinetwork (MN) is a common topological structure in polymerization related manufacturing and artificial high-performance polymers. Currently the experimental and theoretical researches of MNs are generally focused on the deformation and failure mechanism of self-dissimilar tough hydrogels or tough elastomers, in which the topological structures of each sub network are significantly different. In

Ductibor® 500-AS is a hot-stamping steel that has been designed to introduce local ductile regions within hot-stamped tailor-welded blanks (TWBs) used for energy-absorbing sections of automotive structures. This study investigates the flow and fracture behavior of a range of the microstructures of this alloy, corresponding to mostly ferritic (∼ 96% ferrite plus 4% martensite), intermediate ferritic

We develop in this paper a general asymptotic homogenization model pertaining to magnetoelectric shells and sandwich shells composed of an arbitrary distribution of reinforcements or actuators attached to the surface of a thin shell or sandwiched between two shells. The constituents of the reinforced shells are orthotropic and may exhibit piezoelectric and/or piezomagnetic behavior. A set of twenty

Dynamic failure behaviors of fully clamped and simply supported composite sandwich beams with stepwise gradient foam cores subject to low-velocity impact have been investigated experimentally. The sandwich beams with uniform foam core, positive-gradient foam core and negative-gradient foam core are designed and manufactured. The experimental results show that the mass distributions of cores have significant

This paper investigates the behaviour of an underwater toroidal shell storage container filled with compressible fluid under constraint volume condition. The fundamental form of the surface is used to define the geometry of a toroidal shell under an initial unstrained state (IUS), reference state (RS), and deformed state (DS). In the reference state, it is assumed that the toroidal shell storage container

Many composites and their constituents exhibit strength difference (SD) effects. To reduce the computational cost associated to twoscale simulations, the theory of nonuniform transformation field analysis (NTFA, originally proposed by Michel and Suquet, 2003) is extended to consider a general case of SD effects in elastoplasticity, containing several well-known plasticity models like von Mises or Drucker

The unique mechanical properties and transport features of grain boundaries (GBs) in polycrystalline materials have been widely investigated. However, studies which focus on the unique chemo-mechanics phenomena resulting from GBs’ are exceedingly sparse. In this work, a thermodynamically consistent framework has been developed to explore the multi-physics coupling between mechanics and species diffusion

The present paper proposes a new Strain Energy Function (SEF) for incompressible transversely isotropic hyperelastic materials, i.e. materials with a single fiber family. This SEF combines polyconvex invariants forming an integrity basis [1] in a polynomial and exponential form. Compared to a previous attempt for building a SEF based on the same invariants [2], we have reduced the number of material

This paper describes the development of a dual-actuator loading device that was then used to apply asymmetric, transverse end-displacements to laminated beam specimens (silicon/epoxy/silicon) over a range of separation rates. Measurements of the reaction forces, as well as load-point displacements and rotations, were used to determine the normal and tangential components of the crack tip displacements

In this work, a simple and efficient finite element–boundary integral equation coupling method is adopted for studying the buckling of beams and coatings resting on a three-dimensional elastic half-space. For this purpose, a mixed variational formulation based on the Green function of the substrate is adopted by assuming as independent fields beam displacements and contact pressures. Euler-Bernoulli

The extracellular matrix (ECM), forming the cell microenvironment, is a random fiber network whose heterogeneous microstructure serves a vital role in cellular functions such as migration, proliferation, and differentiation. Although prior computational studies used a network of randomly crosslinked fibers for investigating the ECM mechanical response due to the cell contraction, we hereby investigate

Macroscopic austenite-martensite transition zones in thin superelastic NiTi wires subjected to stretching, twisting and their combination were reconstructed via diffraction/scattering computed tomography. The method allows to visualize spatial distributions of both phases from a series of X-ray diffraction scans. A cone-shaped, radially symmetric transformation front was observed in stretched wire

Although continuum frameworks have been developed in the past for studying how material defects behave in solid solutions, recent studies have demonstrated that the self-stress field of the solutes which enter the chemical potential in the prevalent continuum models must be excluded, and instead the image stresses included, in a correct treatment. Here, working within the framework of Gibbs canonical

To develop a plastic constitutive equation for general plastic deformation analysis, it is useful to confirm that the constitutive equation is viable for analyzing mechanical ratcheting in which a small strain accumulates along with cyclic loading. Many constitutive models and analyses on mechanical ratcheting have been proposed. However, most models do not consider distortion and rotation of the subsequent

This paper proposes a new 3D continuous-discontinuous heat conduction model to consider the thermal resistance effect of cracks and dynamic crack propagation during heat transfer. Combining this heat conduction model and the finite-discrete element method (FDEM), we construct a coupled thermomechanical model for solving thermal cracking problems in brittle materials. The mechanical fracture calculation

The bending fracture of an ultra-thin plate containing a thickness-through crack with consideration of surface elasticity is studied in this paper. Based on the Kirchhoff plate theory incorporating surface elasticity, a governing equation is derived for static bending of nanoplates with surface elasticity. The fracture problem of an infinite isotropic elastic nanoplate with a thickness-through crack

3D concrete printing technology has been well developed and applied in various engineering fields. Anisotropy is one of the most important properties for the 3D printed cementitious material. Like fiber reinforced composite matters, if the material property is symmetric in only one plane, then the material is called as monoclinic with 13 independent elastic moduli in its constitutive law. In this study

This work presents a novel approach to efficiently model anodic dissolution in electrochemical machining. Earlier modeling approaches employ a strict space discretization of the anodic surface that is associated with a remeshing procedure at every time step. Besides that, the presented model is formulated by means of effective material parameters. Thereby, it allows to use a constant mesh for the entire

The purpose of this article is to model defect nucleation. The defect is considered as a small volume which evolves as a damaged zone. The damage is described by a transition zone which can be sharp or continuous. In the first case, discontinuities occur and the initiation of defect is based on bifurcation of an equilibrium state. When the transition is continuous, the initiation of the defect is continuous

Three-dimensional lattice structures have the advantages of light-weight and strong design ability, and have good prospects in the application for energy absorption. However, there are seldom design methods of three-dimensional lattice structures for energy absorption, especially a three-dimensional lattice structure design method for energy absorption based on energy absorption diagrams has not yet

Molecular photo-switches as, e.g., azobenzene molecules allow, when embedded into a polymeric matrix, for photo-active polymer compounds responding mechanically when exposed to light of certain wavelength. Photo-mechanics, i.e. light-matter interaction in photo-active polymers holds great promise for, e.g., remote and contact-free activation of photo-driven actuators. In a series of earlier contributions

Origami structures have attracted considerable attention from engineering and science fields, and a variety of numerical methods have been proposed for analysis of this kind of structure. Most of the origami-related numerical studies focus on the static or quasi-static analysis of the folding process. However, the dynamic unfolding of origami triggered by the energy stored in the creases could provide

This contribution presents a phenomenological viscoelastic-viscoplastic constitutive model informed by coarse-grained (CG) molecular dynamics (MD) simulations of pure glassy polystyrene (PS). In contrast to experiments, where viscoplasticity is caused by various effects simultaneously, these effects can be decomposed in MD simulations by adjusting the MD system. In the MD simulations considered here

This paper investigates the effect of the outer adherend geometry on the strength of an adhesively bonded joint. The investigation was carried out by optimizing the joint geometry using two different numerical optimization methods. In genetic algorithm (GA) optimization with high fidelity explicit finite element analysis (FEA) and topology optimization (TOP). Both procedures were utilized on a simplified

Interfacial debonding in layered structures is recognized as a critical failure mode of such structural forms. The way uncertainty of input parameters affects the debonding mechanism is still an open question. In this paper, a methodology for the stochastic analysis of debonding in layered structures is developed. The layered structure is modeled using the cohesive interface approach while parameter

The paper extends the formal structure of the fabric based analysis of cohesion-less granular materials to cemented granular materials such as concrete. The stress-fabric and strain-fabric relationships are derived, and both are seen to be sensitive to particle angularity and maximum particle size. The contributions of the isotropic and anisotropic parts of the micro structural stress and strain are

Next generation lithium-ion batteries (LIBs) cathodes are composed of polycrystalline microstructures where spatial heterogeneity such as grain size is often comparable to the geometric dimension of the cathodes. Incorporating the influence of the aforementioned heterogeneity in a chemo-mechanical continuum description is necessary to address the diffusion induced stress field during electrochemical

This work represents the first step towards the application of machine learning techniques in the prediction of statistical design allowables of composite laminates. Building on data generated analytically, four machine algorithms (XGBoost, Random Forests, Gaussian Processes and Artificial Neural Networks) are used to predict the notched strength of composite laminates and their statistical distribution

We employ a canonical variational framework for the predictive characterization of structural instabilities that develop during the diffusion-driven transient swelling of hydrogels under geometrical constraints. The variational formulation of finite elasticity coupled with Fickian diffusion has a two-field minimization structure, wherein the deformation map and the fluid-volume flux are obtained as

Motivated by a strong coupling between bulk and surface physics, we present two approaches to derive continuum surface models from the three-dimensional, adjacent bulk deformation: projection and relaxation. In contrast to conventional ad-hoc models, properties like the surface stress are consistently derived from a hyperelastic thermodynamic potential. While the projection approach captures classical

The electric-induced Joule heat plays a dominant role for the fracture and failure in electronic devices, particularly in those with bi-material interfaces, yet the effect of Joule heat on temperature elevation and thermal stress for a bi-material interface crack remains incompletely understood. To this end, we develop a coupled electro-thermo-mechanical model for the bi-material interface crack using

Linear stability of magnetic rings consisting of permanently magnetized particles p of the same magnetization is studied. Employing Lagrange’s approach and multipole moments, we determine the stability criterion in closed form. We then apply this criterion to characterize the stability for two scenarios in which the ring is i) compressed by dipolar loading due to a central point dipole and ii) compressed

This paper presents a fracture analysis of ultra-thin coating/substrate structures with interface cracks. For this purpose, an advanced boundary element method (BEM) is adopted. To correctly describe the oscillatory displacement and stress fields near the interfacial crack-tip, a new set of novel special crack-tip elements are implemented. The complex interfacial stress intensity factors (SIFs) can

A novel constitutive framework suitable for material interfaces undergoing large deformations is presented. In contrast to previous works, it accounts for spatially non-constant displacement jumps in the Helmholtz energy by employing their gradient along the interface. This first-order generalization encompasses classic cohesive zone models and surface elasticity theory as special cases. Based on a

The derivation of some class of generalized mechanical models relies on a specific stress expansion without any a priori assumption on the corresponding kinematics. In such situations, their extension to a dynamic setting is not easy, especially when deriving the corresponding generalized inertias since the kinematics is unknown. This paper shows how consistent generalized inertias can be obtained

The onset of frictional motion is mediated by the dynamic propagation of a rupture front, analogous to a shear crack. The rupture front nucleates quasi-statically in a localized region of the frictional interface and slowly increases in size. When it reaches a critical nucleation length it becomes unstable, propagates dynamically and eventually breaks the entire interface, leading to macroscopic sliding

In gradient enhanced crystal plasticity formulations, additional conditions are required on grain boundaries which impact slip system activity in their neighborhood. In the case when gradient effects are caught through a dislocation density tensor, these conditions are prescribed on the flow of this tensor through the boundary or on the dual microforce. Gurtin (2008) proposed to derive the grain boundary

In this paper, an anisotropic failure model proposed by Ganjiani [Ganjiani, M., 2020. A damage model for predicting ductile fracture with considering the dependency on stress triaxiality and Lode angle. European Journal of Mechanics-A/Solids, 104048] is extended to predict the failure phenomena in the materials. The damage model is sensitive to the stress triaxiality and Lode angle parameters. For

In this paper, the mechanical behavior of incompressible transversely isotropic materials is modeled based on the strain energy density function proposed based on a novel framework. As far as physics is concerned, it seems plausible to assume that the strain energy density depends on the deformation. The right Cauchy–Green tensor is a fundamental tool for the deformation description of the solid elements

Friction is much needed for the equilibrium of masonry arches as it transfers load between the voussoirs. In this paper, applying an analytical formulation of the problem, the angle of friction as a geometric constraint on the stereotomy (bricklaying pattern) is investigated to find the possible range of minimum thickness values of circular and elliptical masonry arches under static loads based on

In linear elasticity, the exact first order analytical expressions for each of the effective moduli of n-phase laminate composites are accessible from solving the stress-strain relations under the conditions of uniform stresses and uniform strains normally and transversally to the layers respectively. Several authors have extended successfully this here called “consistency phase boundary conditions”

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 thermodynamically consistent formulation to model anisotropic damage for quasi-brittle materials is proposed. The model is based on proper expressions for the specific Gibbs free energy and the complementary form of the dissipation potential. Damaging of the material is described by a symmetric positive definite second order damage tensor. Especially, the failure surface is formulated in such a way

This study aims to investigate the effects of two testing parameters on the results of the nano-indentation experiment in the heterogeneous particle reinforced composites: (1) the particle distribution pattern, and (2) the methods for calculating the residual projected contact area of the sample under the indenter. For this purpose, several nano-indentation experiments were performed by using Berkovich

This paper is concerned with a theoretical and experimental study of the deployment of inflated curved slender beams. A theoretical model for a beam with effects from restoring force and moment on deployment angle is proposed. Assuming slow deployment, a quasi-static viewpoint is utilized to simplify the model which the buckling cross-section is considered. The relation between deployment angle and

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