Preface to the Second Edition

It has been over ten years since the first edition appeared. In the meantime, utilization of composites has increased in almost every market. Boeing ’s 787 main technological advance is based on widespread incorporation of composites, accounting for about 50% of the aircraft. Its use allows the plane to be lighter and consequently more fuel efficient. It also allows higher moisture content in the cabin, thus increasing passenger comfort. Cost and production time still hamper composite’s utilization in the automotive sector, but like in all other industries, there is a relentless transformation from using classical to composite materials in more and more applications.

This second edition incorporates the advances in knowledge and design methods that have taken place over the last ten years, yet it maintains the distinguishing features of the first edition. Like the first edition, it remains a textbook for senior level undergraduate courses in the engineering disciplines. As such, the discussion is based on math and mechanics of materials background that is common by the senior year, avoiding tensor analysis and other mathematical constructs typical of graduate school.

Experience from instructors all over the world has confirmed that Chapters 1 to 7 can be taught in one semester undergraduate course, assigning Chapters 2 and 3 for independent reading. Those seven chapters remain in the same order in this second edition. Since they have been expanded to accommodate new information, a number of sections have been marked with a (*) to indicate topics that could be skipped on an introductory course, at the instructor ’s discretion.

All ten chapters from the first edition have been revised, updated, and expanded. Three additional chapters have been added. From the material in Chapters 8 to 13, the instructor can pick topics for special projects or tailor a follow-up graduate course. One such course, structural composites design, is now taught at several universities in the USA as an advanced-undergraduate/introductory-graduate course. Two new topics, design for reliability and fracture mechanics, are now introduced in Chapter 1 and applied throughout the book. The composite property tables in Chapter 1 have been expanded in order to support an expanded set of examples throughout the book.

Chapter 2 is thoroughly revised and updated, including new information on modern fibers, carbon nano-tubes, and fiber forms such as textiles. A new section on fabric-reinforcement serves as introduction for the new Chapter 9 on Fabric Reinforced Composites. More material properties for fibers and matrices are given in the tables at the end of Chapter 2, to support the revised and expanded set of examples throughout the book.

Chapter 3, 5, and 6 sustained the least changes. Chapter 3 was revised and updated with a new section on Vacuum Assisted Resin Transfer Molding (VARTM). Chapter 5 and 6 were revised to accommodate the new notation for transformed (rotated) quantities such as Q, which was necessary to accommodate the notation for un-damaged (virgin) quantities, such as Q. The change is necessary to facilitate the discussion about damage in Chapters 7 and 8.

Major advances in prediction of unidirectional-lamina properties were incorporated in Chapter 4, which, as a result, it is heavily updated and expanded. For example, prediction of fracture toughness in modes I and II of the unidirectional lamina are now included, and they serve as background for the discussion about in-situ strength values in Chapter 7. The more complex sections have been re-written in an attempt to help the student and the instructor make faster progress through complex material. In each section, a short summary describes the main concepts and introduces practical formulas for design. This is followed by (*)-labeled sections for further reading, provided the time allows for it. The sections on prediction of longitudinal compression strength, transverse tensile strength, transverse compression strength, and in-plane shear have been re-written in this way. This layout allows for in depth coverage that can be assigned for independent study of be left for later study. In this way, new topics are added, such as Mohr-Coulomb theory, as well as mode I and mode II fracture toughness of composites.

Over the last ten years, the most advance has occurred on the understanding of material failure. Consequently, Chapter 7 has been thoroughly revised to include the most advanced prediction and design methodologies. As in the first edition, Chapter 7 remains focused on design and can be the ending chapter for an undergraduate course, perhaps followed by a capstone design project. However, it now transitions smoothly into Chapter 8, thus providing the transition point to a graduate course on structural composites design.

Chapters 8 to 13 cover applied composites design topics without resorting to finite element analysis, which is left for other textbooks used for more advanced graduate courses [1]. Chapters 8 to 13 are designed for a new course aimed simultaneously at advanced-undergraduate and introductory-graduate level but selected topics can be used to tailor the introductory course for particular audiences, such as civil engineering, materials engineering, and so on.

Chapter 8 includes the methodology used to perform damage mechanics analysis of laminated composites accounting for the main damage modes: longitudinal tension, longitudinal compression, transverse tension, in-plane shear, and transverse compression. The methodology allows for the prediction of damage initiation, evolution, stiffness reduction, stress redistribution among laminae, and ultimate laminate failure.

Chapter 9 includes an in-depth description of fabric-reinforced composites, including textile and non-textile composites. The methodology for analysis of textile reinforced composites includes the prediction of damage initiation, evolution, stiffness reduction, and laminate failure.
Chapters 10, 11, and 12 are revised versions of similarly titled chapters in the first edition. The chapters have been revised to include design for reliability and to correct a few typos on the first edition.

Finally, Chapter 13 is a new chapter dealing with external strengthening of reinforced-concrete beams, columns, and structural members subjected to both axial and bending loads. External strengthening has emerged as the most promising and popular application of composite materials (called FRP) in the civil engineering sector. Therefore, this chapter offers an opportunity to tailor a course on composites for civil engineering students or to inform students from other disciplines about this new market.

In preparing this second edition, all examples have been revised. The number of examples has grown from 50 in the first edition to 75 in this one. Also, the exercises at the end of chapters have been revised. The number of exercises has grown from 115 in the first edition to 155 in this one. I trust that many students, practicing engineers, and instructors will find this edition to be even more useful than the first one.

Ever J. Barbero, 2010

Preface to the First Edition