Extraction of the material stress-strain curve from a dynamic tensile or shear experiment is not straightforward. Indeed, stress and strain are not homogeneously distributed in the specimen, and consequently no one-one relation exists between the measured elongation and strain on one hand, and the measured force and stress on the other hand. This work aims at improving the accuracy of the stres...

A displacement-based finite element for the analysis of laminated composite beams is formulated using strain gradient notation. The definition of the beam’s longitudinal displacement possesses only the independent term (axial displacement) and a term which is linear in the thickness coordinate z. Thus, the finite element is first-order shear deformable. As strain gradient notation is physically...

The non-linear mechanical behaviour of porcine brain tissue in large shear deformations is determined. An improved method for rotational shear experiments is used, producing an approximately homogeneous strain field and leading to an enhanced accuracy. Results from oscillatory shear experiments with a strain amplitude of 0.01 and frequencies ranging from 0.04 to 16 Hz are given. The immediate l...

A correlation imaging velocimetry technique is applied to recover displacement fields in a granular material subjected to extended shear. A thick (10 cm) annular sand sample (grain size: 1 mm) is confined at constant pressure (sigma=0.5 MPa) against a rough moving wall displacing at very low speed (delta=83 microm s(-1)). Localization of the strain rapidly forms a shear band (seven particles wi...

Presented here is a new total-Lagrangian displacement-based finite-element formulation for plates and shells undergoing large displacements and rotations. The theory fully accounts for geometric nonlinearities, general initial curvatures, and extensionality by using Jaumann stress and strain measures, an exact coordinate transformation, and orthogonal virtual rotations. Moreover, transverse she...

With the aim of simulating the behavior of saturated sand with initial static shear (i.e., sloped ground) undergoing undrained cyclic loading, which leads to liquefaction and large cyclic shear strain development, an elastoplastic constitutive model which can describe both monotonic and cyclic torsional shear behaviors of saturated sand under drained and/or undrained conditions is presented. It...

Plastic shear significantly reduces the phase transformation (PT) pressure when compared to hydrostatic conditions. Here, a paradoxical result was obtained: PT of graphitelike hexagonal boron nitride (hBN) to superhard wurtzitic boron nitride under pressure and shear started at about the same pressure ( approximately 10 GPa) as under hydrostatic conditions. In situ x-ray diffraction measurement...

The mechanical properties of brain under various loadings have been reported in the literature over the past 50 years. Step-and-hold tests have often been employed to characterize viscoelastic and nonlinear behavior of brain under high-rate shear deformation; however, the identification of brain material parameters is typically performed by neglecting the initial strain ramp and/or by assuming ...

The potential for structural failure of consolidated clay materials, which is of great importance in many applications, typically are assessed by measuring the localized strain bands that develop under anisotropic load stress. Most methods are precluded from providing a full understanding of the strain anisotropy because they only give two-dimensional information about the stressed clay blocks....

Consolidated-drained triaxial compression tests were conducted to compare the stress-strain and volume change response of sands and clayey sands reinforced with discrete randomly distributed poly-propylene fibers. The influence of various test parameters such as fiber content (0.0%, 0.5% and 1.0% by weight), clay content (0%, 10% and 20% by weight), relative density (50% and 90%) and confining ...