Page 11 - Fiber Fracture

viii PREFACE

CONTENTS OUTLOOK

The contributions are grouped into seven blocks:
Three introductory chapters are the subject of the first section; K.K. Chawla presents
an overview of fiber failure. M. Elices and J. Llorca review available models of fiber
fracture and J.WX Hearle surveys the diverse forms of fiber fracture exhibited in SEM
studies.
The second block is devoted to ceramic fibers, relevant to high temperature metal
and ceramic composites. A.R. Bunsell deals with Sic fibers. Several generations of these
fibers have been produced and the changes in the fracture morphologies between the
generations reveal the modifications have been made to improve their behaviour at high
temperature. M.H. Berger reviews fracture processes in oxide ceramic fibers, stressing
the role of microstructure and contaminants in creep failure at high temperatures.
The main objective of A. Sayir and S.C. Farmer chapter is to examine the fracture
characteristics of a new family of single crystal eutectic oxide fibers manufactured
by directional solidification which offer greater potential for very high temperature
applications owing to their eutectic structure and oxidation resistance.
Glass fibers deserve their own block. They are a major component of the glass
industry, which in the last two decades has seen an explosive growth due to the use
of silica glass fibers as optical waveguides. Such applications require high tensile
strengths over long periods of time, as much as 20 years. P.K. Guptu reviews our present
understanding of the strength of bare glass fibers.
The combination of stiffness, strength, density and cost makes carbon fibers the
best choice for advanced composite materials, and they are dominant in aerospace,
automobile, sports goods and other applications. Their fracture properties, together with
critical steps in their manufacture, are reviewed by J.G. Lavin.
The fifth block is devoted to metallic fibers and thin wires, relevant in the tyre
industry, in electrical and electronic applications as well as in civil engineering. H.U.
Kunzi deals with the influence of fabrication processes and microstructure on the
strength and fracture of metallic filaments, and K. Yoshidu analyzes the influence of
internal defects during the drawing of these metallic wires.
Polymeric fibers are the subject of the sixth section. Polymeric fibers are, perhaps,
commercially the most important of all on account of the magnitude of the textile
industry. They may be classified in two broad categories: natural and synthetic.
High-modulus and high-tenacity synthetic polymer fibers are reviewed by J. WS.
Hearle, stressing the relation between type of loading and fracture mode. I! Termonia
summarizes Monte-Carlo lattice models for the study of the factors controlling the
mechanical strength and mode of failure of flexible polymer fibers. Natural polymeric
fibers are dealt with by C. Wney. Their hierarchical structures are recognised as
providing enhanced toughness compared to just a fine structure. Factors relevant to fiber
assembly and therefore to fracture processes are considered. This block ends with a
chapter devoted to fracture of common textile fibers, by J.W.S. Hearle. The aim of this
chapter is to outline the microstructural changes that occur throughout deformation and
lead to ultimate failure, and to remark that defects are not as strong as controlling feature
of breakage in these extensible textile fibers, as in many other materials.