The finite element (FE) method was used to calculate the axial and radial stress distributions as a function of axial distance, z, from the centre, and radius, r, in an elastic fibre surrounded by a plastic matrix. Plastic deformation of the matrix was considered to exert a uniform interfacial stress, τ , along half the length of the fibre. Axisymmetric models were created for uniform cylindric...

by Nathaniel T. Hollingsworth Annulus fibrosus damage has been shown to come from combinations of bending, lifting, and twisting. Although the these motions can induce annulus fibrosus damage, the stress-strain state of the annulus during these motions is not known. The objective of this project was to develop more complete constitutive models and to investigate annulus fibrosus damage mechanic...

Two novel mathematical models based on polynomial function (PF) and boundary condition method (BCM) are presented for determination of shear stress in interface in steady state creep in short fiber composites under axial loading. Important novelty of this research is determination of shear stress in interface without using of shear lag and imaginary fiber technique (IFT) theories. In these appr...

Delamination is considered for thin elastic 'lms that are bonded to cylindrical substrates and subject to an equi-biaxial compressive pre-stress. Results for both positive and negative curvatures are obtained. The 'lm buckles or de2ects (depending on the sign of the curvature) away from the substrate inducing mixed mode stress intensities at the edge of the delamination. The energy release rate...

A local constitutive model for anisotropic granular materials is introduced and applied to isobaric (homogeneous) axial-symmetric deformation. The simplified model (in the coordinate system of the bi-axial box) involves only scalar values for hydrostatic and shear stresses, for the volumetric and shear strains as well as for the new ingredient, the anisotropy modulus. The non-linear constitutiv...

In this article, thermo-elastic-behavior of a thick-walled cylinder made from a polystyrene nanocomposite reinforced with functionally graded (FG) single-walled carbon nanotubes (SWCNTs) was carried out in radial direction while subjected to a steady state thermal field. The SWCNTs were assumed aligned, straight with infinite length and a uniform layout. Two types of variations in the volume fr...

background: the cervical spine is the most vulnerable part of the vertebral column and the rotational movements are the most dangerous movements which may cause damages to cervical spine. a good treatment option for the cervical disc disease is the replacement of a damaged disc with an artificial disc that has shown satisfactory clinical results. methods: the c4 to c6 vertebrae of a normal subj...

following recent works of several authors like huilgol, bhattacharya etd. and javadpour et al., this paper is to contribute further to the literature of axial flow in a rotational coaxial rheometer. we consider axial flow of herschel bulkley mode1 between two concentric cylinders with the inner one rotating, while the outer cylinder is held stationary. an attempt has been made to direct the ana...

In order to achieve integrated condition in the girth welding of high pressure natural gas transmission pipelines, the weld zones and its surrounding area should have good mechanical properties. Residual stresses are an important defect especially in the girth welding of the pipeline. In this study, two API X70 steel pipes (with spiral seam weld) of 56 inches outside diameter and 0.780 inch wal...

The existence of multi-axial states of stress cannot be avoided in elevated temperature components. It is essential to understand the associated ailure mechanisms and to predict the lifetime in practice. Although metal creep has been studied for about 100 years, many problems are still nsolved, in particular for those involving multi-axial stresses. In this work, a state-of-the-art review of cr...