Elastic modulus

About: Elastic modulus is a research topic. Over the lifetime, 33153 publications have been published within this topic receiving 810247 citations.

Anisotropy of Young's modulus of bone

Abstract: Bonfield and Grynpas1 have compared their experimental data for Young's modulus of elasticity versus the angle of orientation of the specimen to the long axis of bone with a theoretical curve predicted from a calculation for fibre reinforced materials proposed by Currey2. As a result of the poor agreement between the two curves they conclude “… an alternative model is required to account for the dependence of Young's modulus on orientation” (ref. 1). Such an alternative has been under development in my laboratory for the past 8 years (refs 3–7). It is a two-level hierarchical fibre-reinforced composite model which appears to provide a much more suitable description of the behaviour of bone as a fibre-reinforced composite material.

A Microscopic Model for the Reinforcement and the Nonlinear Behavior of Filled Elastomers and Thermoplastic Elastomers (Payne and Mullins Effects)

Abstract: We extend a model regarding the reinforcement of nanofilled elastomers and thermoplastic elastomers. The model is then solved by numerical simulations on mesoscale. This model is based on the presence of glassy layers around the fillers. Strong reinforcement is obtained when glassy layers between fillers overlap. It is particularly strong when the corresponding clusters—fillers + glassy layers—percolate, but it can also be significant even when these clusters do not percolate but are sufficiently large. Under applied strain, the high values of local stress in the glassy bridges reduce their lifetimes. The latter depend on the history, on the temperature, on the distance between fillers, and on the local stress in the material. We show how the dynamics of yield and rebirth of glassy bridges account for the nonlinear Payne and Mullins effects, which are a large drop of the elastic modulus at intermediate deformations and a progressive recovery of the initial modulus when the samples are subsequently put at ...

Effective elastic moduli of two-phase composites containing randomly dispersed spherical inhomogeneities

Abstract: Based on the general micromechanical framework proposed in a companion paper, effective elastic moduli of two-phase composites containing randomly dispersedspherical inhomogeneities are investigated in this paper. At variance with existing micromechanical pairwise interaction models (accurate up to the second-order in particle volume fraction ϕ), the proposed approximate, probabilistic pairwise particle interaction formulationcoupled with the general ensemble-volume averaged field equations leads to a novel, higher-order (in ϕ), and accurate method for the prediction of effective elastic moduli of two-phase composites containing randomly located spherical particles. The relevant ensemble integrals in the proposed formulation are absolutely convergent due to a “renormalization” procedure employed in a companion paper. In accordance with the analogy between the effective shear modulus of an incompressible elastic composite with randomly dispersed rigid spheres and the effective shear viscosity of a colloidal dispersion with randomly dispersed rigid spheres (at high shear rates), the proposed ensemble-micromechanical approach is extended to predict effective shear viscosities of colloidal dispersions at the high-shear limit. Comparisons with experimental data, classical variational bounds, improved three-point bounds, the second-order particle interaction model, and other micromechanical models are also presented. It is observed that significant improvement in predictive capability for two-phase composites with randomly dispersed spheres can be achieved by using the proposed method.

Crack blunting and the strength of soft elastic solids

Abstract: When a material is so soft that the cohesive strength (or adhesive strength, in the case of interfacial fracture) exceeds the elastic modulus of the material, we show that a crack will blunt instead of propagating. Large–deformation finite–element model (FEM) simulations of crack initiation, in which the debonding processes are quantified using a cohesive zone model, are used to support this hypothesis. An approximate analytic solution, which agrees well with the FEM simulation, gives additional insight into the blunting process. The consequence of this result on the strength of soft, rubbery materials is the main topic of this paper. We propose two mechanisms by which crack growth can occur in such blunted regions. We have also performed experiments on two different elastomers to demonstrate elastic blunting. In one system, we present some details on a void growth mechanism for ultimate failure, post–blunting. Finally, we demonstrate how crack blunting can shed light on some long–standing problems in the area of adhesion and fracture of elastomers.

Mechanical Properties of APbX3 (A=Cs or CH3NH3; X=I or Br) Perovskite Single Crystals

Abstract: The remarkable optoelectronic, and especially photovoltaic performance of hybrid-organic-inorganic perovskite (HOIP) materials drives efforts to connect materials properties to this performance. From nano-indentation experiments on solution-grown single crystals we obtain elastic modulus and nano-hardness values of APbX3 (A = Cs, CH3NH3 and X = I, Br). The Youngs moduli are about 14, 19.5 and 16 GPa, for CH3NH3PbI3, CH3NH3PbBr3 and CsPbBr3, respectively, lending credence to theoretically calculated values. We discuss possible relevance of our results to suggested self-healing, ion diffusion and ease of manufacturing. Using our results, together with literature data on elastic moduli, we classified HOIPs amongst relevant materials groups, based on their elasto-mechanical properties.