2283 words - 10 pages

1. INTRODUCTION

Many innovations in aerospace and transportation industries depend on high-performance structural materials. Metal-matrix composites (MMCs) have received considerable attention due to their superior physical, mechanical and thermomechanical properties as compared to those of most conventional materials. MMCs offer a high specific strength, stiffness and wear resistance, that is much higher than that of monolithic materials. They are also capable to survive higher temperature environments. High performance metal matrix composites such as 6061 Al/SiC are now used in, or being considered for use in, variety of applications within the aerospace and automotive industries [1]. ...view middle of the document...

The bonding between the matrix and fiber controls the load transfer efficiency between the fibers and matrix thus, it plays an important role in the behavior of the MMCs [2]. Assuming the bonding to be perfect, it was postulated that the mechanical properties of composite depends more on the properties of fiber as compared to the properties of matrix. The interface region, or interphase, in addition to enabling this load transfer from matrix to fiber, helps in accommodating the strain mismatch between the fiber and matrix and act as a crack blunting layer to minimize crack propagation. In metal matrix composites (MMCs), which have strong fibers and a ductile matrix, strong interfacial bonding is generally desired although, in some cases such as in fatigue crack growth, frictional sliding and fiber pullout are important. The most important of all the composite properties are usually the mechanical properties, since whatever the reason for the choice of a particular composite for some application it must have certain characteristics of shape, rigidity and strength [3]. The mechanical properties of long fibre composites, such as stiffness, can be predicted using several prediction schemes such as the “Rule of Mixtures” and the Halpin-Tsai equations [2]. Several theoretical models have been proposed for the prediction of composite properties from those of the constituent fiber and matrix. Chon and Sun [4] studied the stress transfer between a single fibre and the surrounding matrix by shear-lag theory. In a single fibre model, the properties of fibre/matrix interfaces and the friction on the interfaces after the debonding of fibre and matrix were analyzed using shear-lag theory by Zhou [5].

The aim of this paper is to develop micromechanical model, using commercial finite element package for predicting interfacial stress distribution under tensile loading at different volume fraction of SiC fiber ranging from 10% to 50% in 6061 Aluminum alloy Metal Matrix Composites (AlMMCs).

2. Numerical Methods

The effective properties of composites can be approximately obtained by numerically solving the governing equations over representative volume element (RVE) associated with appropriate boundary conditions [6]. Numerous numerical methods have been employed for solving the microfields, such as early finite difference methods, boundary element methods, and finite element methods (FEM) [7]. The finite element method is a commonly used numerical scheme for determining both global response and the local fields.

3. Modelling of the Composite

Prediction of the mechanical properties of a unidirectional fiber-reinforced composite has been an active research area for the past two decades. Finite element modeling techniques offer a powerful means of performing complex structural analysis. Three-dimensional finite element unit cell models (UCM) have been extensively used in modeling for continuous fiber reinforced metal matrix composites. UCM offer an...

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