Stiff Materials — Fibrous Composites

Abstract

In chapter 4 all the materials considered are more or less pliant, consisting of stiff fibres in a pliant matrix. Under such circumstances the fibres act to introduce anisotropy (as in sea anemone mesogloea, locust extensible i.s.m., artery) to take loads due to internal pressures (maggots, cartilage, plant cells) or to take loads along their length (tendons). These materials are unable to resist bending or compressive loads since the fibres bend or pull past each other. In order to make a material which can resist such loads it is necessary to increase the shear stiffness of the matrix. This will not only stiffen the matrix but also allow the transmission of stresses from one fibre to the next. Alternatively a new phase — ceramic material, usually calcium carbonate or phosphate — is introduced.