Plant cells utilize photosynthesis to produce glucose that is delivered to selected locations to form stiff polysaccharides (e.g., chitin, chitosan, and cellulose), which strengthen the plant structures. Such a photosynthesis-assisted strengthening behavior in plants has rarely been imitated in synthetic material systems. We here propose a synthetic polymer system embedded with extracted plant chloroplasts

Joining soft to hard materials is a challenging problem in modern engineering applications. In order to alleviate stress concentrations at the interface between materials with such a mismatch in mechanical properties, the use of functionally graded interphases is becoming more widespread in the design of the new generation of engineered composite materials. However, current macroscale models that aim

While it is commonly observed that the shape dynamics of mammalian cells can undergo large random fluctuations, theoretical models aiming at capturing cell mechanics often focus on the deterministic part of the motion. In this paper, we present a framework that couples an active gel model of the cell mechanical scaffold with the complex cell metabolic system stochastically delivering the chemical energy

Over the past decade, kirigami—the Japanese art of paper cutting—has been playing an increasing role in the emerging field of mechanical metamaterials and a myriad of other mechanical applications. Nonetheless, a deep understanding of the mathematics and mechanics of kirigami structures is yet to be achieved in order to unlock their full potential to pioneer more advanced applications in the field

Strengthening by needle-shaped β′′ precipitates is critical in Al–Mg–Si alloys. Here, the strengthening is studied computationally at the peak-aged condition where precipitate shearing and Orowan looping are usually considered to have equal strengths. Pseudo-random precipitate microstructures are constructed based on experimental precipitate dimensions and volume fractions at peak aging. A Discrete

We study elastic snap-through induced by a control parameter that evolves dynamically. In particular, we study an elastic arch subject to an end-shortening that evolves linearly with time, i.e. at a constant rate. For large end-shortening the arch is bistable but, below a critical end-shortening, the arch becomes monostable. We study when and how the arch transitions between states and show that the

Recent theoretical and computational progress has led to unprecedented understanding of symmetry-breaking instabilities in 2D dynamic fracture. At the heart of this progress resides the identification of two intrinsic, near crack tip length scales — a nonlinear elastic length scale ℓ and a dissipation length scale ξ — that do not exist in Linear Elastic Fracture Mechanics (LEFM), the classical theory

For materials under cyclic thermal loadings, temperature and strain rate-dependent creep deformation can occur due to the thermal expansion mismatch near material interfaces, leading to deterioration of fatigue life. Simulation of the nonlinear mechanical deformation processes of materials subjected to thermal cycling with high-fidelity numerical models often consume high computational costs due to

Usage, manipulation, transport, delivery, and mixing of granular or particulate media, comprised of spherical or polyhedral particles, is commonly encountered in industrial sectors of construction (cement and rock fragments), pharmaceutics (tablets), and transportation (ballast). Elucidating particulate media’s behavior in concert with particle attrition (i.e., particle wear and subsequent particle

In this study, we investigate in-depth the critical role of the tablet waveform in the fracture mechanics of staggered composites using the "fishnet" homogenization algorithm. A multi-scale fracture analysis protocol has been established for the Mode I crack in staggered composites containing various types of wavy tablets – from anti-trapezoidal to triangular ones. Our analysis finds that the staggered

Constitutive models are of fundamental importance to many biomedical problems such as the rupture prediction of aortic aneurysms. Existing structure-based constitutive models such as the widely used Gasser-Ogden-Holzapfel (GOH) model usually need to specify the number of fiber family which may be difficult to identify for many kinds of tissues. In this study, we developed a novel hyperelastic model

We propose a one-dimensional, nonconvex elastic constitutive model with higher gradients that can predict spontaneous fracture at a critical load via a bifurcation analysis. It overcomes the problem of discontinuous deformations without additional field variables, such as damage or phase-field variables, and without a priori specified surface energy. Our main tool is the inverse deformation, which

Symmetry-breaking instabilities in high- pressure phase transformation produce the counterintuitive phenomenon of “volume collapse” producing only shear radiation, with little, or no, volumetric component, even under conditions of full isotropy, and explain the mystery of the long-standing observations in deep-focus earthquakes (400-700 km). Due to instability, at a critical “nucleation pressure”,

The cyclic plasticity behaviour and failure mechanism of the cathode material in lithium-ion batteries urgently need to be understood due to the cyclic lithium-ion diffusion-induced stress during charging-discharging process. Many researches have focused on the shakedown and ratcheting responses of lithium-ion battery anode. However, the systematic investigation on the plasticity behaviour of lithium-ion

Infrastructure materials, such as rocks and concrete, exhibit an array of intricate and interrelated dynamic mechanical behaviors that act across a broad range of size scales. Modeling these dynamic behaviors is important for understanding safe design, application, and maintenance practices. One particular and fascinating nonlinear dynamic mechanic response - slow dynamics - is characterized by a self-recovering

We formulate a path-independent J-integral for the elastodynamic problem expressed in the frequency domain. We show that the path-independence of the integral can be exploited in order to derive ansatz-free identities and rigorous inequalities in certain problems arising in geotechnical engineering. By way of illustration, we specifically consider the problem of assessing seismic pressures on retaining

The paper is concerned with the vibration characteristics of the Coronavirus family. There are some 25–100 receptors, commonly called spikes protruding from the envelope shell of the virus. Spikes, resembling the shape of a hot air balloon, may have a total mass similar to the mass of the lipid bi-layer shell. The lipid proteins of the virus are treated as homogeneous elastic material and the problem

We systematically design composite structures using multi-material topology optimization to achieve tunable elastic responses under finite deformations. We formulate an inverse problem where the errors between the actual (numerical) and the prescribed force–displacement curves are minimized. The framework harnesses multiple hyperelastic materials with distinct constitutive relations, which enlarge

Hard magnetorheological elastomers (h-MREs) are essentially two phase composites comprising permanently magnetizable metallic inclusions suspended in a soft elastomeric matrix. This work provides a thermodynamically consistent, microstructurally-guided modeling framework for isotropic, incompressible h-MREs. Energy dissipates in such hard-magnetic composites primarily via ferromagnetic hysteresis in

Soft dielectric elastomers with high relative permittivity, very low modulus and high electric breakdown strength have emerged as promising materials for various applications as sensors, actuators and in energy harvesting and soft robotics. We study the intricate deformation behaviour of a soft dielectric elastomer tube of finite length and closed ends, that carries a dead load, is internally pressurised

High-temperature oxidation in polymers is a complex phenomenon, driven by the coupled diffusion–reaction process, causing changes in the amorphous network structure and resulting in property degradation. Prolonged oxidation in polymers results in the formation of a coarse, oxide layer on the outer surface and induces spontaneous cracking inside the material. In this paper, we present a chemical reaction-driven

The adhesion of fibrillar dry adhesives, mimicking nature's principles of contact splitting, is commonly characterized by using axisymmetric probes having either a flat punch or spherical geometry. When using spherical probes, the adhesive pull-off force measured depends strongly on the compressive preload applied when making contact and on the geometry of the probe. Together, these effects complicate

Despite being commonly credited with initiating the field of cavitation in elastomers, the famed poker-chip experiments of Gent and Lindley (1959) have yet to be fully explained. One likely reason for their elusiveness is that it had long been presumed that cavitation in elastomers was a phenomenon that could be explained solely on the basis of the elasticity of the elastomer at hand. Of late, full-field

We demonstrate experimentally and theoretically the broadband sub-diffraction and ultra-high energy density focusing of elastic wave inside planar gradient-index (GRIN) plate lenses based on thickness variation. The full width at half maximum is ~0.40 times the minimum wavelength inside the lens λ0 or ~1/11 times the incident wavelength in the background plate λB. We analytically elucidate the underlying

Shear wave elastography (SWE) enables the probing of the mechanical properties of soft tissues in vivo and has been demonstrated to be a promising technique for the diagnosis of diseases such as staging liver fibrosis, evaluating artery stiffening, and detecting cancers. In this study, a porohyperviscoelastic model is presented to address the shear wave elastography of soft tissues with emphasis on

Lap shear and peel are common tests for soft materials. Their results, however, are rarely compared. Here we compare lap shear and peel as tests for measuring toughness. We prepare specimens for both tests by using stiff layers to sandwich a layer of a polyacrylamide hydrogel. We introduce a cut in the hydrogel by scissors, pull one stiff layer at constant velocity, and record the force. In lap shear

The thermo-mechanical response of micro-architectured tungsten coatings is characterized in the temperature range of 293 to 673 K using both in situ micro-compression experiments inside a scanning electron microscope (SEM) as well as image-based crystal plasticity finite element method (CPFEM) simulations. The experiments were conducted on micropillar-like specimens that were focus ion beam milled

The axisymmetric three-body, double-unilateral contact problem for an elastic sphere is treated by analytical techniques. It is assumed that the elastic sphere is put on the surface of an elastic layer of finite thickness and, afterwards, is indented at the upper pole of the sphere with a rigid spherical punch. Friction is neglected at both contact interfaces. A first-order asymptotic solution for

Steady progress in the miniaturization of structures and devices has reached a scale where thermal fluctuations become relevant and it is thus important to understand how such fluctuations affect their mechanical stability. Here, we investigate the buckling of thermalized square sheets under either compression or shear. We demonstrate that thermal fluctuations increase the critical buckling load compared

The continuum dislocation dynamics framework for mesoscale plasticity is intended to capture the dislocation density evolution and the deformation of crystals when subjected to mechanical loading. It does so by solving a set of transport equations for dislocations concurrently with crystal mechanics equations, with the latter being cast in the form of an eigenstrain problem. Incorporating dislocation

Nature's materials are generally hybrid composites with superior mechanical properties achieved through delicate architectural designs. Inspired by the precipitation hardening mechanisms observed in biological materials as well as engineering alloys, we develop here dual-phase mechanical metamaterial composites by employing architected lattice materials as the constituent matrix and reinforcement phases

The Jarzynski relation, as an equality form of the second law of thermodynamics, represents an exact thermodynamic statement that is valid arbitrarily far away from equilibrium. This remarkable relation directly links the equilibrium free energy difference between two states and the probability distribution of the work done along a process that drives the system from one state to the other. Here, we

The rupture of the interface joining two materials under frictional contact controls their macroscopic sliding. Interface rupture dynamics depend markedly on the mechanical properties of the bulk materials that bound the frictional interface. When the materials are similar, recent experimental and theoretical work has shown that shear cracks described by Linear Elastic Fracture Mechanics (LEFM) quantitatively

Measurement of in-plane elasticity of thin sheets often leverages out-of-plane poking or bulging, also known as indentation or bulge tests. For linear elastic sheets, a load-cubic deflection relation has been frequently assumed so that the stiffness of the sheet could be readily extracted. However, we find that recent results of indentation and bulge tests on 2D materials do not support the assumption

We investigate non-Hermitian degeneracies, also known as exceptional points, in continuous elastic media, and their potential application to the detection of mass and stiffness perturbations. Degenerate states are induced by enforcing parity-time symmetry through tailored balanced gain and loss, introduced in the form of complex stiffnesses and may be implemented through piezoelectric transducers.

The elongation of a tank-treading red blood cell (RBC) under shear flow was numerically simulated to understand its mechanical characteristics. The boundary element method was used to couple the viscoelastic deformation of the cell membrane and viscous flow of the surrounding fluids. Accordingly, it was found that elongation deformation and inclination angle, which depend on the cell membrane's viscoelasticity

Future developments of lighter, more compact and powerful motors – driven by environmental and sustainability considerations in the transportation industry – involve higher stresses, currents and electromagnetic fields. Strong couplings between mechanical, thermal and electromagnetic effects will consequently arise and a consistent multiphysics modeling approach is required for the motors’ design.

The quasi-brittle nature of rocks challenges the basic assumptions of linear hydraulic fracture mechanics (LHFM): namely, linear elastic fracture mechanics and smooth parallel plates lubrication fluid flow inside the propagating fracture. We relax these hypotheses and investigate in details the growth of a plane-strain hydraulic fracture in an impermeable medium accounting for a rough cohesive zone

This article focuses on the time-domain propagation of elastic waves through a 1D periodic medium that contains non-linear imperfect interfaces, i.e. interfaces exhibiting a discontinuity in displacement and stress governed by a non-linear constitutive relation. The array considered is generated by a, possibly heterogeneous, cell repeated periodically and bonded by interfaces that are associated with

In this work, we present a model parameter calibration procedure for a physics-based crystal plasticity model. The calibration process utilizes a powerful statistics-based Bayesian calibration method. Calibration of the crystal plasticity parameters makes use of experimentally-measured data, i.e. compressive stress–strain response, from 〈100〉 and 〈123〉 single crystal copper dynamically loaded via Kolsky

Plane strain finite element analyses are used to model the experiments of Mu et al. (2014, 2016) for a thin metal layer confined between elastic solids. The thin metal layer undergoes elastic-plastic deformations, here modelled by strain gradient plasticity, while the rest of the solid deforms only elastically. Plane strain is assumed and finite strains are accounted for. The microscopic boundary condition

Numerical modelling on the compressive response of self-healing polymer foams embedded with novel, bilayered alginate capsules was developed based on the coupled pore fluid diffusion and stress simulations. Micromechanical models were developed to link the damage variable to permeability as well as the saturation to the capillary pressure within damaged polymer foams. These micromechanical models were

This paper presents a robust methodology aimed at assessing the fracture toughness of materials undergoing quasi-static or dynamic loads leading to crack propagation. The proposed implementation relies on the J-Integral concept and it identically operates with data fields obtained by Finite Element modeling or fields experimentally obtained by Digital Image Correlation technique. The capability of

The aim of this paper is to offer a fresh perspective on the classic concept of critical state (CS) in granular materials by suggesting that CS can be defined through the use of a single proportional strain test. In classic conventional testing, CS manifests itself under constant lateral stress and controlled strain in one given direction whenever continuous shearing is applied without change being

The multi-stability of composite shells often exhibits complex mechanical behaviors, accompanied by large deformation, strong nonlinearity and multiple equilibrium branches. We present a numerical framework for stability analysis of laminated composite shells, which is capable of efficiently computing nonlinear equilibrium paths and critical points, and effectively assessing the stability of the structure’s

Lattice truss structures fabricated by additive manufacturing (AM) technique are highly desired in the aerospace science and technology field for their ultra-light and multi-functional properties. However, AM constraints are seldom considered in the mechanical design of lattice units, resulting in noteworthy discrepancies between the actual mechanical performance and designed property of lattice structures

This paper develops an uncertainty quantified, parametrically homogenized constitutive model (UQ-PHCM) for microstructure-sensitive modeling and simulation at the structural scale. The PHCMs are thermodynamically consistent, macroscopic constitutive models, whose parameters are explicit functions of Representative Aggregated Microstructural Parameters or (RAMPs) that represent statistical distributions

Dislocation dynamics simulations were used to calculate the energy barrier of cross-slip via Friedel–Escaig mechanism in face centered-cubic copper. The energy barrier in the unstressed case was found to be 1.9 eV, as reported by Ramírez et al. (2012). The energy barrier was reduced by applying an external stress. The most effective way of reducing it, was by applying a compressive stress on the glide

Adhesive peeling of a thin elastic film from a substrate is a classic problem in mechanics. However, many of the investigations on this topic to date have focused on peeling from substrates with flat surfaces. In this paper, we study the problem of peeling an elastic thin film from a rigid substrate that has periodic surface undulations. We allow for contact between the detached part of the film with

This study focuses on investigating the effects of the localized stresses that develop during formation of zirconium hydrides on the redistribution of hydrogen atoms in the zirconium matrix. A coupled mass diffusion and crystal plasticity finite element approach is used. The effects of the transformation strain associated with the formation of hydrides within various combinations of soft-hard grains

Ionic polymer metal composites (IPMCs) consist of an electroactive polymeric membrane plated with metal electrodes. They hold promise as actuators and sensors for soft robotics and biomedical applications. Their capabilities ensue from the motion, within the membrane, of a fluid phase consisting of ions dispersed in a solvent. Toward a thorough understanding of IPMC multiphysics, we propose a large

Polyether ether ketone (PEEK) is a semi-crystalline thermoplastic polymer with excellent thermo-mechanical properties, bio-compatibility, corrosion resistance, and 3D printability. Due to these merits, it has wide applications in aeronautics and biomedical devices. However, PEEK's excellent thermo-mechanical properties come from its complicated crystalline domains, making it hard to predict and to

Size effects in metal plasticity are widely accepted, and different theoretical approaches to handle the phenomenon are developing in the literature. The present work considers the Fleck and Willis (2009b) framework, and creates a new gradient enhanced rate-independent crystal plasticity FE-implementation. The study considers both energetic and dissipative gradient hardening and strengthening, and

We propose a method for deriving equivalent one-dimensional models for slender non-linear structures. The approach is designed to be broadly applicable, and can handle in principle finite strains, finite rotations, arbitrary cross-sections shapes, inhomogeneous elastic properties across the cross-section, arbitrary elastic constitutive laws (possibly with low symmetry) and arbitrary distributions of

The interplay between interfacial shear stress and adhesion has been an active but controversial subject of adhesive contact mechanics, which is currently plagued by diverse, sometimes contradicting, predictions. Recently, McMeeking et al. showed that a reversible interface slip parameter plays an essential role in determining how interfacial shear stress affects adhesion for a Johnson-Kendall-Roberts

We study the frictional behavior of both elastic and viscoelastic thin coatings bonded to a seemingly rigid substrate and sliding against a rough profile in the presence of Coulomb friction at the interface. The aim is to explore the effect of the coupling between the normal and tangential displacement fields arising from the finiteness of the material thickness and to quantify the contribution this