Modified Stress Tensors for Anisotropic Behavior of Granular Materials

Effect of Stress Triaxiality on Yielding of Anisotropic Materials under Plane Stress Condition

The triaxiality of the stress state is known to greatly influence the amount of plastic strain which a material may undergo before ductile failure occurs. It is defined as the ratio of hydrostatic pressure, or mean stress, to the von Mises equivalent stress. This paper discusses the effects of stress triaxiality on yielding behavior of anisotropic materials. Hill-von Mises’s criteria for anisot...

Stress Fluctuations for Continuously Sheared Granular Materials.

Experiments on continuously sheared granular materials (glass spheres) with diameters 1.0 # d # 5 mm show large fluctuations in the normal stress, sstd. Experiments are carried out in an annular Couette geometry for rotation rates 0.003 , Ù u , 1 radys. Power spectra from sstd, Psvd, show rate invariance in the fluctuations: Ù uPsvd is a function only of vy Ù u, independent of Ù u. Ù uPsvd depe...

Multi-Mechanism Anisotropic Constitutive Model for Granular Materials

A microscopic framework for developing phenomenological constitutive models was recently developed for granular materials. The plastic strains are computed from relative sliding and rolling of particles, and the resulting microscopic theory is called the sliding-rolling theory. Within this framework, a phenomenological constitutive model was then developed to describe the anisotropic stress-str...

A Theoretical Study of Wall Ironing for Anisotropic Workharden Materials

On the Three Stress Tensors for Linearly Elastic Constrained Materials

In this paper we obtain the constitutive equation for the second Piola-Kirchhoff stress tensor according to the linearized finite theory of elasticity for hyperelastic constrained materials. We show that in such a theory the three stress tensors (Cauchy stress tensor, first and second Piola-Kirchhoff stress tensor) differ by terms that are first order in the strain, while in classical linear th...