Do materials prepared from identical compositions of constituting ingredients always exhibit similar mechanical properties? The answer is negative for most structural materials, as has been demonstrated by extensive studies on various factors such as the effects of processing and microstructures. However, the same question has seldom been addressed in the case of polymeric gels. In this work, by using

Micro- and nano-sized blisters can form spontaneously when two-dimensional (2D) crystals are transferred onto substrates because liquid molecules that are initially adsorbed on 2D material and substrate surfaces can be squeezed and trapped by interfacial forces. In this work, we use a combination of experiments, continuum theories, and coarse-grained molecular dynamics (CGMD) simulations to investigate

Due to the unique properties of biopolymer gels, they are extensively used in the food industry and biomedical applications such as drug delivery. Different from rubber-like materials, the constituting chains in many biopolymer gels randomly interlock with neighbouring chains by means of physical rather than covalent cross-linking. Such polymer networks are characterized by two principal regions: the

We derive a one-dimensional (1d) model for the analysis of bulging or necking in an inflated hyperelastic tube of finite wall thickness from the three-dimensional (3d) finite elasticity theory by applying the dimension reduction methodology proposed by Audoly and Hutchinson (2016). The 1d model makes it much easier to characterize fully nonlinear axisymmetric deformations of a thick-walled tube using

SiC composites at elevated temperatures are prone to oxidation, prompting the use of environmental barrier coatings to limit or prevent the ingress of oxidants. Cracks in such coatings can provide fast diffusion pathways that can lead to accelerated local oxide growth. The localized oxide confined at the tip of such features generates significant stress due to the large molar volume change associated

Abstract not available

Actin-based motility is a complex process in which the actin-polymerization is the primary force-generating motor machinery. It can produce protrusive forces through actin filaments polymerization and cross-link during lamellipodia protrusion in migrating cells and it is responsible for the intracellular motion of certain pathogens in infected host cells. We propose a multi-physics model for actin-based

To develop better diagnosis and treatment techniques of cardiovascular disease such as aneurysm, further understandings of the biomechanical mechanisms and failure behaviors of blood vessels is urgent. Importantly, blood pressure, residual stress, loads from surrounding tissues, and fluid-structure interactions greatly influence the spatiotemporal evolution of deformation and damage of blood vessels

We investigate pattern transformations of periodic hydrogel systems that are triggered by swelling-induced structural instabilities. The types of microstructures considered in the present work include single-phase and two-phase voided hydrogel structures as well as reinforced hydrogel thin films. While the observed transformations of the single-phase structures show good agreement with experimental

Liquid crystal elastomers (LCEs) are a class of active polymers of increasing interest, because of their excellent actuation performances. To quantify the actuation performances and understand the thermomechanical behavior, many theoretical models were developed, mainly based on the free energy framework with uniaxial order tensor, which, however, cannot well capture the biaxial liquid crystal alignment

Mechanical deformations induced by expansion within an elastic material which is spirally-wound in layers with a thin inextensible reinforcing material are considered. The motivation is to understand behaviour of spirally-wound batteries where both the active material and the metal current collectors expand due to changes in lithiation and/or temperature. This paper considers a spiral made from a single

This work focuses on computing the homogenized elastic properties of rocks from 3D micro-computed-tomography (micro-CT) scanned images. The accurate computation of homogenized properties of rocks, archetypal random media, requires both resolution of intricate underlying microstructure and large field of view, resulting in huge micro-CT images. Homogenization entails solving the local elasticity problem

Stretchable devices composed of layered hyperelastic materials are under rapid development to interact with human body, and merge the gap between human and machines. These devices are required to sustain large deformation without mechanical failure over a long time, which remains a challenge. Compared to the fast movement in functions design, the failure mechanism of layered hyperelastic structures

Copper nanowires have received extensive attention for their potential applications in optics, electricity and catalysis, while oxidation erosion has become the biggest obstacle to their widespread application. Here, we present a chemo-mechanical coupling model to investigate the interlayer cracking behaviors of nanowires during oxidation. In contrast to existing chemo-mechanical models, the present

This contribution presents a generalized mechanical interface model for nonlinear kinematics. The interface’s response is non-coherent, i.e. allows for a jump in the deformations and for cohesive failure, and also includes interfacial (in)elasticity, which means that an additional membrane stiffness is introduced in the interface. This can result in a jump in the tractions across the interface and

We formulate a thermodynamically-consistent electro-chemo-mechanical gradient theory which couples electrochemical reactions with mechanical deformation and damage in solids. The framework models both species transport across the solid host due to diffusion/migration mechanisms and concurrent electrochemical reaction at damaged zones within the solid host, where ionic species are reduced to form a

Shaping two-dimensional (2D) crystals with well-defined edges along specific directions remains technically challenging due to the intrinsic lattice discreteness and anisotropy in their fracture toughness. The patterns of crystal cleavage are determined by the fracture resistance and loading conditions, and usually display kinking features. We show that the fracture of single-crystalline 2D films (MoS2

This paper presented integrated electromigration (EM) studies through experiment, theory, and simulation. First, extensive EM tests were performed using Blech and standard wafer-level electromigration acceleration test (SWEAT)-like structures, which were fabricated on four-inch wafers. Second, a molecular dynamics (MD) simulation-based diffusion-induced strain was incorporated into the existing coupled

This paper presented a comprehensive experimental and simulation study for thermomigration (TM) accompanying electromigration (EM) at elevated current densities. Both Blech and standard wafer-level electromigration acceleration test (SWEAT)-like test structures, with aluminum (Al) as a carrier, were used for testing and analysis. In Part I of our study (Cui et al., 2023a), the experimental and numerical

In this paper, we have developed and demonstrated a novel high-velocity impact experiment to study dynamic fragmentation of additively-manufactured metals. The experiment consists of a light-gas gun that fires a conical nosed cylindrical projectile, that impacts axially on a thin-walled cylindrical tube fabricated by 3D printing. The diameter of the cylindrical part of the projectile is approximately

Recently, higher-order topological insulators (HOTIs) as a novel frontier of topological phases of matter have been induced in mechanical systems, opening new routes to manipulate the propagation of elastic waves. Here, second-order mechanical topological insulators (SMTIs) implemented by mechanical metamaterials are systematically investigated in the rectangular lattice, the kagome lattice, the square

Some high-throughput experiments aim to test many samples simultaneously under nominally the same conditions. However, whether a particular high-throughput experiment does so must be certified. We previously described a high-throughput experiment to study the statistics of rupture stretch of materials. In such an experiment, a large set of samples were tested simultaneously. We noticed a systematic

High-performance carbon nanotube (CNT) fibers inevitably encounter complicated thermal environments while used in aerospace structures and intelligent actuators. Catastrophic damage is unavoidably induced due to the loss of their mechanical properties. Herein, a modified Hopkinson bar and an in-situ SEM tensile equipment were introduced to study the high-temperature time-dependent mechanical behaviors

Data-driven and deep learning approaches have demonstrated to have the potential of replacing classical constitutive models for complex materials, displaying path-dependency and possessing multiple inherent scales. Yet, the necessity of structuring constitutive models with an incremental formulation has given rise to data-driven approaches where physical quantities, e.g. deformation, blend with artificial

To design increasingly tough, resilient, and fatigue-resistant elastomers and hydrogels, the relationship between controllable network parameters at the molecular level (bond type, non-uniform chain length, entanglement density, etc.) to macroscopic quantities that govern damage and failure must be established. Many of the most successful constitutive models for elastomers have been rooted in statistical

Fluid-saturated porous elastic materials, made up of connected networks of solid ligaments and characteristically having open pores, are commonly found in geological, biological and engineering materials. Surface effects can affect significantly the mechanical performance of such porous materials at macro scale, especially when the solid ligaments and the pores have micro or nano scale sizes. In the

Tissue porosity pressure mechanics play a vital role in the physiological workings and anatomical structures of soft tissue. Further understanding relationships between the pressurized state of the tissue and its function by noninvasive measurements may lead to new diagnostic methods for identifying early stages of disease pathology. The purpose of this study was to investigate the ability of Magnetic

Point defect distribution in the vicinity of discontinuities plays important role in the transport properties of nonstoichiometric ionic solids. Here, considering dopants and oxygen vacancies as the major point defects in doped ceria, we develop a Monte Carlo model to examine how the stress field of edge dislocations affect point defect distribution in their surroundings. Point defects are considered

Multiscale experiments in heterogeneous materials and the knowledge of their physics under shock compression are limited. This study examines the multiscale shock response of particulate composites comprised of soda-lime glass particles in a PMMA matrix using full-field high speed digital image correlation (DIC) for the first time. Normal plate impact experiments, and complementary numerical simulations

Intergranular fatigue crack nucleation has been reported to occur commonly at high angle grain boundaries (HAGBs) but seldom at low angle GBs (LAGBs) during persistent slip band (PSB)-GB interactions. However, the mechanistic understanding of the role of GB misorientation angles in affecting the GB fatigue cracking remains limited due to the lack of quantitative descriptions. Here a theoretical framework

The gap test is a new type of fracture test developed in 2020, in which the end supports of a notched beam are installed with gaps that close only after the elasto-plastic pads next to notch introduce a desired constant crack-parallel compression σxx (also called the T-stress). The test uses the size effect method to identify how such a compression alters the material fracture energy, Gf, and the characteristic

Origami-based multistable metamaterials have been recognized as a promising platform for diverse applications due to their exceptional mechanical properties. However, the current state of the art in designing origami metamaterials is mostly ad-hoc and narrowly focused on a particular mechanical property. In other words, there is a lack of basic research on deriving generic and systematic methodologies

Soft actuators typically require time-varying or spatially modulated control to be operationally effective. The scope of the present paper is to show, theoretically and experimentally, that a natural way to overcome this limitation is to exploit mechanical instabilities. We report experiments on active filaments of polyelectrolyte (PE) gels subject to a steady and uniform electric field. A large enough

Building on an analogy to ductile fracture mechanics, we investigate the energetic cost of debris particle creation during adhesive wear . Macroscopically, Reye proposed in 1860 that there is a linear relation between frictional work and wear volume at the macroscopic scale. Earlier work suggested a linear relation between tangential work and wear debris volume also exists at the scale of a single

Biological membranes and vesicles play a vital role in critical physiological processes like endocytosis, cell division, and cell motility. Over decades, statistical and continuum mechanics studies have provided phenomenal insights into the mechanics of these membranes and their biophysical implications. However, most studies, until recently, have focused entirely on passive (or “dead”) membranes that

Many common engineering alloys are strengthened by precipitates with plate-like geometries. The mechanics of precipitation strengthening, while well resolved with spherical precipitates, are less well understood for plate-like geometries. In this work, we employ discrete dislocation dynamics simulations to study precipitation strengthening by θ′ precipitates in AlCu. We show that Orowan looping with

Poor ductility heavily limits the industrial application of magnesium (Mg) alloys, and pyramidal dislocations are an important deformation mode for ductility enhancement. In this work, discrete dislocation dynamics (DDD) simulations were performed to study the mechanical behavior and dislocation evolution of Mg single-crystals compressed along c-axis. Especially, basal-transition and cross-slip algorithms

We develop a comprehensive geometrically-exact theory for an end-loaded elastic rod constrained to deform on a cylindrical surface. By viewing the rod-cylinder system as a special case of an elastic braid, we are able to obtain all forces and moments imparted by the deforming rod to the cylinder as well as all contact reactions. This framework allows us to give a complete treatment of static friction

In this paper, we extend the discrete-to-continuum procedure we developed in Español et al. (2018) to derive a continuum variational model for a hexagonal twisted bilayer material in which one layer is fixed. We use a discrete energy containing elastic terms and a weak interaction term that could utilize either a Lennard-Jones potential or a Kolmogorov–Crespi potential. To validate our modeling, we

We present a new phase-field formulation for the formation and propagation of a compaction band in high-porosity rocks. Novel features of the proposed formulation include (a) the effects of inertia on the rate of development of compaction bands, and (b) degradation mechanisms in tension, compression, and shear appropriate for dynamic strain localization problems where disturbances propagate in time

Pre-existing flaws in highly stretchable elastomers trigger fracture under large deformations. For multifunctional materials, fracture mechanics may be influenced by additional physical phenomena. This work studies the implications of hard magnetics on the fracture behaviour of ultra-soft magnetorheological elastomers (MREs). We experimentally demonstrate that MREs with remanent magnetisation have

Abstract not available

The ability to precisely directing and controlling longitudinal (P) and transverse (S) waves in 2D solids along an arbitrary trajectory has attracted significant research interest and is crucial for practical applications such as imaging, cloaking, and wave focusing. Here, we report, design and examine an inhomogeneous lattice-based polar medium for ideal elastic waveguide, whose microstructures are

It is now a well-established fact that even simple topology variations can drastically change the fracture response of structures. With the objective of gaining quantitative insight into this phenomenon, this paper puts forth a density-based topology optimization framework for the fracture response of structures subjected to quasistatic mechanical loads. One of the two key features of the proposed

A mechanistic understanding of morphogenesis in biology, the fabrication of advanced meta surfaces with specific functionalities and structures with enhanced energy dissipation often have in common that the combined effects of energy dissipation due to viscoelasticity and a loss of stability govern both their mechanical response and their final forms. In this paper we show that the interplay between

We assess if a characteristic length for a non-linear interfacial slip instability follows from theoretical descriptions of sliding friction. We examine friction laws and their coupling with the elasticity of bodies in contact and show that such a length does not always exist. We consider a range of descriptions for frictional strength and show that the area needed to support a slip instability is

Crystalline nanowires exhibiting a wide range of size-dependent fracture and failure modes have been extensively studied, yet the fracture behaviors of amorphous materials and their size dependence remain elusive. Here extensive atomistic simulations are performed to reveal the deformation and fracture behaviors in a broad class of amorphous nanowires with varying sizes, including CuZr, CuZrAl, FeP

We make use of a micromechanical energy estimate proposed in the companion paper (Peigney, 2023) to study strain Lüders-like localization in polycrystalline NiTi specimen under tension. Under the assumption that only the most favorably oriented martensitic variant is active in each grain, it is shown that the homogeneous equilibrium problem can be solved analytically for fiber textures (as commonly

When an underground heat exchanger is subjected to a surface load on the ground and temperature change inside, the stress transfer between the thermal tank and the earth may cause the deformation and destruction of the tank. The bi-material thermoelastic fundamental solution of two-jointed dissimilar half-spaces is applied to elastic and thermal analysis of spherical heat storage tanks, where the continuity

This work presents a numerical investigation into the dynamic crack penetration vs. deflection at a material interface, for materials exhibiting strain rate dependent damage evolution. The rate dependence of damage manifests as an increased strength and fracture energy (or toughness) at higher strain rates. For this purpose, a strain rate dependent continuum damage mechanics (CDM) based model is considered

For a thin layer of elastomer sandwiched between two rigid blocks, when the blocks are pulled, numerous cavities grow in the elastomer like cracks. Why does the elastomer grow numerous small cracks instead of a single large crack? Here we answer this question by analyzing an idealized model, in which the elastomer is an incompressible neoHookean material and contains a penny-shaped crack. To simulate

Understanding the deformation behavior of biopolymer hydrogels would aid in the design of artificial hydrogels and nanoparticle-based drug delivery systems, which have been extensively used in the fields of biomedicine. Here, we develop a mechanistically motivated constitutive model to elucidate the structural evolution of biopolymer hydrogels. A free energy function includingconfigurational entropy

Interfacial mechanics between elastoplastic fiber and elastic substrate/matrix is of critical importance for a range of applications such as metal nanowires on polymer substrate for flexible and stretchable electronics and metal fibers in ceramic matrix for multifunctional composites. Here analytical models of an elastoplastic fiber (e.g., nanowire) on the as-prepared or chemically treated elastic

It is shown that a compound elastic structure, which displays a dynamic instability, may be designed as the union (or ‘fusion’) of two structures which are stable when separately analysed. The compound elastic structure has two degrees of freedom and is made up of a rigid rod connected with two springs to a smooth support, which evidences a jump in the curvature at the equilibrium configuration. Instability

The mechanical behavior of freestanding metal thin films (gold, aluminum, and nickel-molybdenum-tungsten alloy) is characterized using micro-tensile testing and membrane deflection experiment (MDE). Micro-tensile and membrane samples are simultaneously fabricated on a single wafer to avoid microstructural differences. A constant strain rate MDE methodology is developed to directly compare each test

Numerous topology optimization formulations have been proposed in order to enhance structural resistance to material failure. A clear line can often be drawn between those methods which attempt to constrain local failure criteria and those that explicitly model the failure physics during the optimization process. In this work the former method is extended in a manner inspired by the mathematical form