Motivated by recent experimental investigations of the mechanical behavior nanoporous metal we explore an efficient and robust method for generating 3D representative volume elements (RVEs) with strikingly similar behavior. Our approach adopts Cahn's a Gaussian random field taking superposition standing sinusoidal waves fixed wavelength but in direction phase. In its theory part, our study describes closed-form expressions how solid fraction affects binarization level, mean structure size,...

Most metamaterials with negative Poisson's ratio and/or thermal expansion coefficient possess relatively low stiffness. In this work, a novel hybrid-honeycomb structure enhanced stiffness is proposed. It consists of two merged hexagonal honeycombs. Analytical and computational homogenization methods are used to evaluate the effective thermoelastic properties. expressions Young's modulus, ratio, given. We show that properties widely tunable by tailoring microstructural geometry constituent...

We investigate the influence of various critical structural aspects such as pore density, distribution, size and number on deformation behavior nanoporous Cu64 Zr36 glass. By using molecular dynamics finite element simulations an effective strategy to control strain localization in heterostructures is provided. Depending distribution heterostructure, upon tensile loading glass showed a clear transition from catastrophic fracture localized one dominant shear band, ultimately homogeneous...

We explore the elastic and plastic Poisson's ratios, νE νP, of nanoporous gold, using digital image correlation during compression experiments including load/unload segments. The two coefficients differ significantly, with independent ligament size, L, a trend for νP∝L at not too large L. Disorder in network ligaments may explain why is smaller than predicted by lattice-based models. Finite element simulations, based on Deshpande–Fleck constitutive law, validate data analysis. law captures...

Thin-walled metamaterials based on triply periodic surfaces are relatively simple, light-weight structures that, as shown in the following, possess extraordinary material properties. As opposed to their filled counterparts, these can be tuned elastically isotropic and isotropically auxetic - latter is property of extending all directions under tensile loading one direction. Considering level topologically equivalent minimal types Primitive, Diamond, Gyroid I-WP, we focus stiffness, symmetry,...

Metamaterials are man-made, usually periodically microstructured materials with at least one uncommon property, e.g., auxeticity. Often, their properties due to specific microstructural layouts in addition constituent materials. In this work, we explore the influence of on effective elasticity a two-phase composite consisting infilled re-entrant honeycomb microstructure. We show that non-auxetic becomes auxetic if Young's modulus contrast between two phases exceeds certain critical value....

A class of three-dimensional lattice structures cubic symmetry is designed by spatially assembling and merging a number two-dimensional re-entrant honeycomb structures. We demonstrate that the effective thermoelastic properties these are widely tunable tailoring microstructural geometry and/or constituent materials. Particularly, they possess negative Poisson's ratios. If inclined non-inclined walls dissimilar thermal expansion coefficients, can further attain isotropic or positive...

This paper treats the computational modeling of size dependence in microstructure models metals. Different gradient crystal plasticity strategies are analyzed and compared. For numerical implementation, a dual-mixed finite element formulation which is suitable for parallelization suggested. The ends with representative example polycrystals.

This paper introduces an efficient method to automatically generate and mesh a periodic three-dimensional microstructure for matrix-inclusion composites. Such models are of major importance in the field computational micromechanics homogenization purposes utilizing unit cell models. The main focus this contribution is on creation cubic representative volume elements (RVEs) featuring geometry topology suitable application boundary conditions framework finite element simulations. Our...

The Small Punch (SP) test serves the screening of mechanical material properties and their degradation in a virtually non-invasive way. It requires robust frameworks for derivation microstructure–mechanical property correlation. tensile yield stress σy is commonly associated with an elastic-plastic transition force Fe via = αFe/h2 h denoting SP disc thickness dimensionless coefficient α considered constant. Here it shown that cannot be taken as Instead new self-consistent data reduction...

Low modulus biomaterials are in focus as potential candidates for biomedical implants ensuring a fast healing of hard tissues. The close match between elastic properties an implant material and bone critical to eliminate stress-shielding effect. In this study, we synthesized low interpenetrating-phase composite Ti Mg by liquid metal dealloying. Its Young's value is the range that found human which allows applications material. Unexpectedly, (17.6 GPa) several times lower than each individual...

The modelling and computation of the coupled thermal mechanical response human skin at finite deformations is considered. model extends current models to account for thermally- mechanically-induced deformations. Details solution highly nonlinear system governing equations using element method are presented. A representative numerical example illustrates importance considering problem a rigid, hot indenter in contact with skin.

Predicting the influence of surface on effective elastic properties nanoscale structures and nanomaterials remains a challenge, which we here address both levels, continuum atomic. Density Functional Theory (DFT) computation at atomic level yields first reliable excess parameters for (111) (001) surfaces gold. At level, derive closed-form expressions behavior that can be combined with DFT-derived to obtain axial, torsion, bending stiffness circular nanowires elasticity. The two approaches...

We study effective elastic properties of 3D bicontinuous random composites (such as, e.g., nanoporous gold filled with polymer) considering linear and infinitesimal elasticity using asymptotic homogenization along the finite element method. For generation microstructures, a leveled-wave model based on works Cahn (1965) Soyarslan et al. (2018) is used. The influences volume size, phase contrast, relative fraction phases applied boundary conditions computed apparent moduli are investigated....

We design auxetic 3D interlocking brick-and-mortar composites inspired by nacre - a natural strong and resilient high-performance material. The influences of geometrical parameters base material properties on their effective elastic are systematically investigated finite element simulations computational homogenization. numerical results indicate that the exhibit tunable negative Poisson's ratios properly tailoring underlying microstructures. It is revealed behavior therein attributed to...