this paper presents a macro model to predict unreinforced masonry structures in plane behavior. the model is based on the concept of multilaminate theory. in the past, the method has been used to model behavior of soil, disregarding the cohesion and the tensile strength. regarding its mathematical base, and the possibility of applying in other cases, this method is used to predict the ultimate ...

Experiments were carried out in which the dependence of the fractional softening on temperature, time and strain rate was determined in a 304H stainless steel. Three prestrain ranges were identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the DRX critical strain: strongly strain dependent softening by SRX alone with softening kinetics control...

experiments were carried out in which the dependence of the fractional softening on temperature, time and strain rate was determined in a 304h stainless steel. three prestrain ranges were identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the drx critical strain: strongly strain dependent softening by srx alone with softening kinetics control...

Recent Bauschinger-type tests conducted on a twinning-induced plasticity (TWIP) steel highlights the important contribution of internal stresses to work hardening [1]. Along this line we present Bauschinger experiments in a Fe-22Mn wt.%-0.6C wt.% TWIP steel. The mechanical behaviour upon load reversal shows transient and permanent softening effects. Determination of the internal stress from the...

We use Bai’s conservation equation for cracks, and Rice and Tracey’s equation for the growth of a spherical void in an infinite medium to derive an evolution equation for damage in an anisotropic material. It is then used to delineate the instability strain in a thin anisotropic sheet deformed in a plane stress state of deformation, and obeying Hill’s yield criterion. Assuming that strainand st...

Shear instabilities in the form of shear bands are often observed during high speed, plastic deformations of metals. According to one theory, their formation is attributed to eeective strain-softening response, which results, at high strain rates, as the net outcome of the innuence of thermal softening on the, normally, strain-hardening response of metals. In order to test the core instability ...

The present paper is concerned with the development of a micromechanical model of the hardening, rate-sensitivity and thermal softening of b.c.c. crystals. In formulating the model we specifically consider the following unit processes: double-kink formation and thermally activated motion of kinks; the close-range interactions between primary and forest dislocations, leading to the formation of ...

This study is focused on anomalous strain-rate-dependent behaviour of bacterial cellulose (BC) hydrogel that can be strain-rate insensitive, hardening, softening, or strain-rate insensitive in various ranges of strain rate. BC hydrogel consists of randomly distributed nanofibres and a large content of free water; thanks to its ideal biocompatibility, it is suitable for biomedical applications. ...