Book Review: Fiber Reinforced Composites

Take a look at any engineer's bookshelf, and you will see several college textbooks. Although the purpose of most textbooks is to teach engineering concepts, most of them also make good general references.

Fiber Reinforced Composites is more of a pure textbook. As I was reading through it, I was constantly reminded of a graduate level seminar. The material covered was very interesting, but the topics tended to jump around quite a bit.

Although heavy on theory, Dr. Ashbee is always careful to point out the physical implications of a formula. For example, the very first paragraph of the book defines specific modulus, then shows that its square root is equal to the speed of sound in the material. Ultimate strength is then defined as

where UTS is ultimate tensile strength, r is mass density, and g is gravitational acceleration. Using this definition, specific strength has units of length, and is equal to the longest length of fiber that can be suspended under its own weight.

This is a simple example, but it shows how the author is always careful to relate engineering mechanics to materials science. There is also plenty of graduate-level material in this book.

Consider the chapter on environmental degradation. Most authors would stick to expansion coefficients. Dr. Ashbee, though, gets right into the physics of water absorption and shows how osmotic pressure causes crack growth. To get through the chapter, you will need to work through gas laws and other thermodynamics equations, stress distributions in finite-length fibers, chemical reactions with graphite fibers, and fracture mechanics.

Joining of composites, either to other composites or to metals, always presents some challenges. The chapter on joining has good coverage of galvanic corrosion, stress distributions in adhesive bonds, joint geometry, and testing of joints.

Because this is meant to be a textbook, it contains an ample number of sample problems. Each chapter has a few worked problems, plus several problem statements at the end. Most problems require interdisciplinary knowledge, and some are designed to require library research.

Perhaps one of my favorite features were the laboratory problems that end each chapter. These ranged from conducting specimen tests to demonstrating physical principles. The lab assignment at the end of Chapter Two shows how to make a French knitting machine from four push pins and a thread spool, which then is used to make braided tubes from carbon and Kevlar fibers. The tubes are then stretched onto glass rods, impregnated with resin, cured, and tested in torsion.

My only real complaint about the book is the lack of chapter end notes or a bibliography. References are given as footnotes. If a reference is cited a second time, the footnote number refers to the original note. There were several times when I found myself flipping through the book, skimming the numbers at the bottom of the pages in order to find a note referred to near the back of the book.

Fiber Reinforced Composites is available for purchase from the publisher.

Details: Fundamental Principles of Fiber Reinforced Composites, by Ken Ashbee, published by Technomic Publishing Company, 1993, ISBN 0-87762-923-4.
1. Specific Strength and Specific Modulus; 2. Materials and Processing; 3. Anisotropy of Stress; 4. Anisotropy of Elasticity; 5. Elasticity of Orthotropic Laminates; 6. Anisotropy of Thermal Expansion; 7. Stresses in a Plate Arising from the Presence of a Hole; 8. Fracture and Fracture Mechanics; 9. Anisotropy of Strength; 10. Environmental Degradation; 11. Joining and Repair; 12. Non-Destructive Evaluation