Biologically-derived and chemically-treated collagenous tissues such as glutaraldehyde-treated bovine pericardium (GLBP) are widely used in many medical applications. The long-term cyclic loading-induced tissue fatigue damage has been identified as one of the primary factors limiting the durability of such medical devices and an in-depth understanding of the fatigue behaviors of biological tissues

Understanding the feature-rich buckling-dominated behavior of thin elastic ribbons is ripe with opportunities for fundamental studies exploring the nexus between geometry and mechanics, and for conceiving of engineering applications that exploit geometric nonlinearity as a functioning principle. Predictive mechanical models play an instrumental role to this end. As a direct consequence of their physical

Besides being ubiquitous in engineering applications such as Polyethylene terephthalate, materials with tension-compression asymmetry can also be found in lots of biological systems, e.g., muscle and brain tissue. However, the effect of tension-compression asymmetry at finite strains has not been well studied, especially lack of theoretical model and analytical solutions. In this work, based on a bi-modulus

The method of mechanical (or robotic) palpation tomography assumes the use of a rigid indenter for in vivo detecting the presence of tissue lesions by the quasi-static contact probe inspection of the surface of the human body. The interpretation of the indentation data requires the inverse solution to contact problems for inhomogeneous substrates. A particular interest has been drawn to quantitative

At low strain, geometrically necessary dislocations (GND) confined in the close vicinity of grain boundaries can be approximated as a dislocation wall structure called a GND facet. Analytical solutions derived from Field Dislocations Mechanics (FDM) theory allow calculating the stress components associated with the GND facets but are unable to account for the stress field variation induced by finite

Water injection laboratory experiments in weak, poorly consolidated sandstones show evidence that the peak injection pressure is much larger than the one predicted by the Haimson-Fairhurst breakdown criterion. A model based on poroelasticity, fracture mechanics, and lubrication theory is constructed to simulate the laboratory experiments. It aims at computing the propagation of a bi-wing hydraulic

Several experiments have demonstrated the existence of an electro-mechanical effect in many biological tissues and hydrogels, and its actual influence on growth, migration, and pattern formation. Here, to model these interactions and capture some growth phenomena found in Nature, we extend volume growth theory to account for an electro-elasticity coupling. Based on the multiplicative decomposition

This work is concerned with the purely dissipative version of a well-established model of rate-independent strain-gradient plasticity. In the conventional theory of plasticity the approach to determining plastic flow is local, and based on the stress distribution in the body. For the dissipative problem of strain-gradient plasticity such an approach is not valid as the yield function depends on microstresses

Macroscopic wear experiments in mid 1950s suggested an empirical wear relation: wear volume is linearly proportional to load and sliding distance. Recent asperity-level wear experiments and simulations reported a breakdown of this law at the nanoscale, posing the fundamental question: Is the macroscopic wear relation recoverable at the asperity level? Here we show that discrepant observations of wear

We consider a two-dimensional cellular vertex model, modeling the mechanics of epithelial tissues. The energy of a planar configuration penalizes deviations in each cell from a reference perimeter P0 and a reference area A0. We study the variational limit of this model as the cell size tends to zero, obtaining a continuum variational model. For P02/A0 below a critical threshold, which corresponds to

The hydraulic circular and elliptical bulge tests have been widely used in extracting mechanical properties of sheet materials. Theoretical analysis of bulge tests usually requires the kinematic relationships between the apex strains, radii of curvatures and dome heights to be established. Most of the available analytical solutions are derived on a case-by-case basis and are often limited to circular

Mylar balloons are popular in funfairs or birthday parties. Their conception is very simple: two pieces of flat thin sheets are cut and sealed together along their edges to form a flat envelope. Inflation tends to deform this envelope in order to maximize its inner volume. However, although thin sheets are easy to bend and hardly resist compressive loads, they barely stretch, which imposes non-trivial

Bridging effects in heterogeneous composite materials are traditionally treated as tractions lumped at the crack surface. This conventional equivalence, however, may fail to reveal the fundamental mechanisms of composite toughening. Hereby, a damage-plastic multiphase model is proposed and developed which is capable of capturing the engaging bridging mechanisms of fiber reinforced cementitious composites

We consider the effect of an array of plates or beams over a semi-infinite elastic ground on the propagation of elastic waves hitting the interface. The plates/beams are slender bodies with flexural resonances at low frequencies able to perturb significantly the propagation of waves in the ground. An effective model is obtained using asymptotic analysis and homogenization techniques, which can be expressed

This paper investigates the problem of a radial (or a penny-shaped) hydraulic fracture propagating in a permeable reservoir. In particular, we consider the fluid exchange between the crack and ambient porous media as a pressure-dependent process. In most of the existing models, the fluid exchange process is represented as one-dimensional pressure-independent leak-off described by Carter’s law. We modify

Spatially-varying stress fields can be obtained from atomistic simulations as weighted averages over a phase function that depends on the positions and momenta of the atoms and the interatomic forces between them. However atomistic stress fields exhibit significant nonphysical noise on atomic length scales even under uniform loading conditions. This makes it difficult to obtain accurate stress estimates

The homogenized medium of the gyro lattice with the mechanical quantum Hall effect, here denoted as the gyroscopic elastic medium, is governed by a new set of elastodynamic equations with the chiral density. This paper presents a generic theory based on the Stroh formalism to disclose the non-reciprocal Rayleigh waves supported by the gyroscopic medium. The Stroh formulation is investigated in the

We present a framework which unifies classical phenomenological J2 and crystal plasticity theories with quantitative dislocation mechanics. The theory allows the computation of stress fields of arbitrary dislocation distributions and, coupled with minimally modified classical (J2 and crystal plasticity) models for the plastic strain rate of statistical dislocations, results in a versatile model of

This paper proposes an efficient contact model for a viscoelastic layered half-space where coating and substrate have different creep functions (i.e. different viscoelastic behaviours). The problem is formulated in three dimensions for an imposed pressure and shear field. The influence coefficients are calculated with the Papkovich-Neuber potentials and computation performed using Discrete Convolution

Head-to-head comparisons are made between calculations and experimental data on shock-driven pore collapse in the transparent material, poly(methyl methacrylate) (PMMA). Simulations are performed using SCIMITAR3D, an Eulerian sharp-interface multi-material code, while plate impact experiments are visualized using ultra-high speed x-ray imaging. The experiments and simulations are conducted over a wide

The existence of a nucleation instability is demonstrated at the vanishing of the path-independent M integral in linear anisotropic elasticity so that a region that is arbitrarily small can grow at constant potential energy. It yields a quadratic equation for the critical pressure to balance the Eshelby dissipation and nucleate an inclusion undergoing both change in density and change in bulk modulus

We study jump instability phenomena due to external disturbances to an axially loaded beam resting on a nonlinear foundation that provides both lateral and axial resistance. The lateral resistance is of destiffening-restiffening type known to lead to complex localisation phenomena governed by a Maxwell critical load that marks a phase transition to a periodic buckling pattern. For the benefit of having

Although the solution of hyperbolic partial differential equations in elastic-plastic media is of major importance in solid mechanics, the mathematical complexity of such problems increases with the space dimensionality. As a result, the development of analytical solutions is in general not possible. Whereas the wave structure resulting from given external loads is known and well understood for one-dimensional

We investigate the possibility of achieving high fracture toughness and high strength by the design of lightweight (density below water) metallic micro-architectured materials. The micro-architectured materials were manufactured by drilling a hexagonal array of holes in plates of an aluminum alloy, and the fracture toughness was evaluated via three-point bend tests of single-edge notch specimens. The

Vector solitary waves are nonlinear waves of coupled polarizations that propagate with constant velocity and shape. In mechanics, they hold the potential to control locomotion, mitigate shocks and transfer information, among other functionalities. Recently, such elastic waves were numerically observed in compressible rubber-like laminates. Here, we conduct numerical experiments to characterize the

One of the contentious issues associated with the high-cycle fatigue of Nitinol, a nominally equiatomic alloy of nickel and titanium, is the claim that increasing the applied mean strain can increase, or at least have no negative impact, on the fatigue lifetime, in conflict with reported behavior for the vast majority of other metallic materials. To investigate this in further detail, cyclic fatigue

Microtransfer printing is a manufacturing technique that relies on controlled selective delamination between two interfaces to transfer thin solid films and chips. Stamps in these processes are often designed to leverage strategies that modify the interfacial stress distribution at the stamp interface to achieve a specific adhesion response, however the effect of a modified stress distribution at the

An experimental and analytical investigation is conducted to study the underwater interaction of implosion pressure pulses with large plates. Two plates with stiffnesses significantly apart are investigated experimentally in a large-diameter pressure vessel for their Fluid-Structure Interaction (FSI) phenomena during proximal implosions of low stiffness metallic shells. High-speed photography, in conjunction

Adhesion of soft materials is commonly characterized by strength and toughness. Their applicability, however, is often questionable even for widely used test methods. Here we study lap shear using a combination of experiment, theory, and computation. Lap shear has long been used to measure adhesion strength of soft materials, but our experiments show that the measured adhesion strength is constant

Soft viscoelastic polymers and gels are commonly used a wide range of applications owing to their softness and the ability to accommodate large deformations. Their applicability is however often limited by their tendency to fracture in ways that are cannot be predicted by conventional elastic fracture mechanics. Our understanding of fracture in this class of solid has particularly been hindered by

We examine the problem of an elastic film bonded to an elastic substrate and subjected to compressive stress (induced by growth of the film or lateral compression of the whole system). Following the linear analysis previously carried out to determine the critical growth/compression ratio required to induce wrinkling in the film, we carry out a weakly-nonlinear analysis to derive an amplitude equation

A novel, concurrent multiscale approach to meso/macroscale plasticity is demonstrated. It utilizes a carefully designed coupling of a partial differential equation (pde) based theory of dislocation mediated crystal plasticity with time-averaged inputs from microscopic Dislocation Dynamics (DD), adapting a state-of-the-art mathematical coarse-graining scheme. The stress-strain response of mesoscopic

The asymptotic fields at the tip of a crack in a fiber-reinforced neo-Hookean sheet are derived. The investigation is carried out for the case of a strain energy function for a fiber-reinforced hyperelastic material motivated by composite mechanics (Guo et al., 2006, 2007ab), where the fibers are also neo-Hookean. The resulting asymptotic deformation and stress fields depend qualitatively and quantitatively

A broadband elastic wave absorption by a sub-wavelength and lightweight structure is of considerable significance in vibration suppression, especially for low frequencies in plate-like structure. However, it has always been a great challenge. In this research, we systematically study the flexural wave diffraction in a thin plate. Based on the diffraction mechanism, we propose the concept of sub-wavelength

Hydrogels experience complex environment stimuli (evaporation, temperature, electric fields, external loads, and constraints) when used in stretchable electronic devices, soft robots, and many other applications. In addition, it always needs time for hydrogels to respond when these stimuli change. Therefore, the transient responses of hydrogels to multi-stimuli should be studied carefully. Existing

The dynamic rheology of a complex granular material system strongly depends on the imposed stress state. However, drawing a clear physics based picture of dynamic granular flow is challenging due to the heterogeneous nature of granular materials, as well as the overwhelming difficulties in carrying out dynamic experiments. Here, pressure-shear plate impact (PSPI) is utilized to load a granular boron

A number of recent medical procedures such as histotripsy rely on inertially-dominated oscillating gas cavities (i.e. bubbles) inside soft tissue. As a first approximation, soft tissue can be modeled by linear or nonlinear elasticity models and the equations describing bubble dynamics in such media have been derived in previous works. However, these models assume that the bubble remains perfectly spherical

In most voided metallic materials, the failure process is often driven by the competition between the phenomena of void coalescence and plastic strain localization. This paper proposes a new numerical approach that allows an accurate description of such a competition. Within this strategy, the ductile solid is assumed to be made of an arrangement of periodic voided unit cells. Each unit cell, assumed

It is useful to describe the deformation characteristics of long biological macromolecules, such as deoxyribonucleic acid (DNA), by means of terms such as “bending”, “stretching”, or “twisting”. These terms are borrowed from classical beam theory, a traditional and widely known subfield of continuum mechanics, whereas the standard numerical modeling procedure for macromolecules, which is molecular

The physics behind the interaction of inclusions on lipid membranes is relevant to the self-assembly of proteins that mediate exo- and endo-cytosis in cells. These interactions can be quantified in terms of free energy changes that can be calculated using Gaussian integrals since the potential energy of a lipid membrane with inclusions can be expressed as a quadratic form in terms of a stiffness matrix

Smart materials and smart structural systems are of paramount importance in the development of modern technological applications such as in bioengineering (tissue engineering, drug delivery, microscale surgery, …), packaging, data storage, molecular machines, smart sensors and actuators, etc. Smart polymers, often termed as responsive polymers, show physical or chemical changes in response to environmental

Photopolymerized hydrogels are critical to soft devices, mechanobiology, regenerative medicine, and next generation drug delivery. However, the optimization of processing protocols for all of these applications of photopolymerized hydrogels has been at least semi-empirical due to the lack of a comprehensive predictive framework. Herein, we developed the first comprehensive predictive framework for

Recently, ferromagnetic soft continuum robots – a type of slender, thread-like robots that can be steered magnetically – have demonstrated the capability to navigate through the brain's narrow and winding vasculature, offering a range of captivating applications such as robotic endovascular neurosurgery. Composed of soft polymers with embedded hard-magnetic particles as distributed actuation sources

Ferroelectric materials are widely used in our daily life and many advanced industrial products. The understanding of their fracture behavior has been in the focus of research for decades, since the success of their application requires reliability and durability. For ferroelectric fracture behavior, different fracture criteria have been proposed and the influence of various mechanical-electric loading

Many plastics show necking and drawing behavior in tension, sometimes called “cold drawing”. In contrast, elastomers stretch homogeneously in tension. We examine the tensile behavior of rubber–plastic laminate composites using 3D finite element simulations and an analytical model. A rate-independent constitutive behavior was adopted in which the modulus at small-strain, strain hardening at large strain

The mathematical description of elastoplasticity is a highly complex problem due to the possible change from elastic to elasto-plastic behavior (and vice-versa) as a function of the loading path. Advanced physics-based plasticity models usually feature numerous internal variables (often of tensorial nature) along with a set of evolution equations and complementary conditions. In the present work, an

The prediction of compressive properties of foams at large strains and in a wide range of strain rates is still an open issue. In this work we propose a visco-hyperelastic formulation, suitable for large finite strain applications, for the prediction of the compressive response of foams that takes into account the viscoelasticity of the polymer, nonlinear damping, nonlinear behaviour of the cellular

Flexoelectricity refers to phenomena that polarization is coupled with strain gradient and stress is coupled with electric gradient. It occurs in all dielectrics, and becomes significant under a sharp conductive tip in piezoresponse force microscopy (PFM), under which large gradients in electromechanical field naturally arise. Here we analyze direct and converse flexoelectric effects under such a scanning

This paper presents a poromechanical model for drying of unsaturated porous media valid for a large range of relative humidity. Using the proper laws of thermodynamics, this model is derived and permits to account for different effects that contribute to the effective stress development: the average pore pressure effect, the energy of the interfaces effect, the surface adsorption effect and the Shuttleworth

We present a simplified computational framework based on the cohesive finite element method (CFEM) for predicting the macroscale fracture measures such as KIC and JIC of ductile metals as functions of microstructural attributes. Currently, no systematic approach exists to explicitly quantify the effects of grain and grain boundary behavior on the fracture measures of polycrystalline materials. Our

Clustering of ligand-binding receptors of different types on thickened isles of the cell membrane, namely lipid rafts, is an experimentally observed phenomenon. Although its influence on cell’s response is deeply investigated, the role of the coupling between mechanical processes and multiphysics involving the active receptors and the surrounding lipid membrane during ligand-binding has not yet been

We develop a numerical investigation on the dynamic loading mitigation performance of Bouligand inspired bionic structures subjected to striker impacts and explosion induced blast overpressure loadings. A novel computational modelling approach based on Timoshenko beam theory as well as nonlinear Hertz contact theory has been employed to predict the nonlinear dynamic response of the bio-inspired helicoidal

Architectured biological composites with sutural tessellations possess excellent static and dynamic mechanical properties. In this study, a dynamic analysis of the damping performance of composites with sutural interfaces is carried out based on the viscoelastic tension-shear model. Analytical formulae that connect the damping properties (i.e., the loss modulus, storage modulus, and loss factor) of

Cellular adhesion via the formation of molecular bond clusters is a fundamental biological phenomenon. Cell adhesion forces can be measured by various advanced techniques with adjustable probe stiffness. To quantitatively understand how the stiffness of a loading device may influence the measurement of these forces, we consider an idealized theoretical model of a cluster of molecular bonds that are

Twenty years in since their introduction, it is now plain that the regularized formulations dubbed as phase-field of the variational theory of brittle fracture of Francfort and Marigo (1998) provide a powerful macroscopic theory to describe and predict the propagation of cracks in linear elastic brittle materials under arbitrary quasistatic loading conditions. Over the past ten years, the ability of

The formation and subsequent growth of cracks in brittle solids caused by indentation loading is investigated using a phase field modeling of fracture. While this methodology, at first glance, appears to be a promising tool for handling problems like the present one including crack initiation from an initially defect-free surface, its actual application reveals a number of critical issues. The paper