An account is given of the development of the idea of a yield stress for solids, soft solids and structured liquids from the beginning of this century to the present time. Originally, it was accepted that the yield stress of a solid was essentially the point at which, when the applied stress was increased, the deforming solid first began to show liquid-like behaviour, i.e. continual deformation...

A general phenomenological reaction-diffusion model for flow-induced phase transitions in complex fluids is presented. The model consists of an equation of motion for a nonconserved composition variable, coupled to a Newtonian stress relations for the reactant and product species. Multivalued reaction terms allow for different homogeneous phases to coexist with each other, resulting in banded c...

We investigate the use of two distinct and complementary approaches to measuring the viscometric properties of low viscosity complex fluids at high shear rates up to 80,000 s−1. Firstly we adapt commercial controlled-stress and controlled-rate rheometers to access elevated shear rates by using parallel plate fixtures with very small gap settings (down to 30 μm). The resulting apparent viscositi...

When the shear stress measured in Large Amplitude Oscillatory Shear (LAOS) deformation is represented as a two-dimensional Lissajous-Bowditch curve, the corresponding trajectory can appear to self-intersect and form secondary loops. This self-intersection is a general consequence of a strongly nonlinear material response to the imposed oscillatory forcing and can be observed for various materia...

Batra [1] used a linear relationship between the second Piola-Kirchhoff stress tensor S and the Green-St. Venant strain tensor E to study finite simple shearing and finite simple extension deformations of an elastic body. In each case he found that the tangent modulus (i.e. the slope of the shear stress vs. the shear strain curve or the slope of the axial stress vs. the axial stretch curve) is ...

The flow of valley glaciers is examined in the light of recent laboratory experiments on the behaviour of ice under load. Simple expressions are given for the velocity distributions in some cases of laminar flow, and the modification of a pure laminar flow theory necessary to explain the formation of transverse crevasses and thrust planes is considered. The paper ends with some remarks about th...

Using high-speed confocal microscopy, we measure the particle positions in a colloidal suspension under large-amplitude oscillatory shear. Using the particle positions, we quantify the in situ anisotropy of the pair-correlation function, a measure of the Brownian stress. From these data we find two distinct types of responses as the system crosses over from equilibrium to far-from-equilibrium s...

The model of the lung as an elastic continuum undergoing small distortions from a uniformly inflated state has been used to describe many lung deformation problems. Lung stress-strain material properties needed for this model are described by two elastic moduli: the bulk modulus, which describes a uniform inflation, and the shear modulus, which describes an isovolume deformation. In this study ...

The mechanical characteristics of rock salt have an important influence on the safety of the salt cavity. The acoustic emission (AE) technique was used to analyze the generation of microcracks in rock salt under uniaxial compression condition. By monitoring acoustic emission in whole process of stress strain curve under uniaxial compression test, the damage characteristic of rock salt is obtain...