Rami Eliasi

Modeling of functionally graded materials in dynamic analyses

Abstract In this investigation, functionally graded material is modeled in several different ways. Five models are presented, two of which simulate fiber phases and three simulate particle phases. For fibers, there is a model in which the detailed micro-structure is simulated and one in which the material is represented by layers such that the volume fraction of the fibers in each layer changes. For the particles, a model with layers is employed and two models with continuously changing material parameters are presented. Four different dynamic input loads are applied to the detailed micro-structure to examine its effect. The finite element method is employed to determine the effective stress. Then one of the dynamic loads which simulates a step function is applied to all models. It is observed that there are no significant differences in the effective stresses at particular points within the time domain. The amplitude of the wave for each model is quite similar. The phase of the wave shifts as time increases. Thus, in the space domain, differences are observed in the effective stress at a particular time. As may be expected, the stresses are rather high within the fibers in the detailed micro-structural model. It is concluded that a continuously changing material model is a good candidate for carrying out dynamic analyses of functionally graded material.

A methodology for measuring interface fracture properties of composite materials

AbstractA methodology is presented for measuring interface fracture properties of composite materials. A bimaterial Brazilian disk specimen with a crack along the interface is employed. The specimen is analyzed by means of the finite element method and a conservative integral to determine stress intensity factors as a function of loading angle and crack length. A weight function is employed to determine the effect of residual curing stresses on the stress intensity factors. These are combined to determine the critical interface energy release rate

Finite Element Analysis of CoSi2 Nanocrystals on Si(001)

\mathcal{G}

Effect of Residual Stresses on Delamination Cracks in Fiber Reinforced Composites

ic as a function of stress intensity phase angle Ψ for tests carried out on a glass/epoxy material pair.

Fatigue life analysis of a cannon barrel

The aim of this investigation is to measure the interface fracture toughness of a woven composite. For this purpose, double cantilever beam (DCB) specimens are tested to measure the load as the delamination grows. The specimen is composed of 15 layers of a carbon–epoxy, balanced weave with alternate layers containing fibers in the

Toughness of a ±450 Interface

0^{\circ }\!/90^{\circ }