Composite Materials — An Overview

Abstract

The essence of composite materials technology, particularly in the field of fibre composites, is the ability to put strong, stiff reinforcing elements (fibres) in a matrix in the right place, in the right orientation, with the right volume fraction. Implicit in this approach is the concept that in making the composite material one is also making the final product. This means that there must be very close collaboration between those who design composite materials at the micro scale and those who design and manufacture the final engineering component. The importance of this concept is illustrated by reference to the structure of wood. The primary structure consists of fibre tracheids which are hollow tubes. These are bonded together and are oriented in the axial and radial growth directions. The walls of the tracheids are themselves composite materials and consist of many layers of well-oriented cellulose fibrils held together with lignin. The orientation of the fibre tracheids and cellulose fibrils is related to the load bearing requirements of the tree.