| Book Review: Spatially Reinforced Composites | |
The use of composites continues to grow because they have excellent
strength and stiffness properties compared to traditional
materials. These advantages, however, are primarily limited to
in-plane properties. When out-of-plane or through-thickness properties
are important, composites tend to perform poorly.
This problem is being addressed by the development of 3D
composites. Such composites can be made in many ways, each of which
has unique benefits. Predicting the properties of 3D composites is
a complex process, made more difficult by the wide variety of
geometries. In Spatially Reinforced Composites, the authors
present an overview of the different types of 3D composites and the
theories used to predict their strengths and stiffnesses.
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SRC begins with a description of different types of spatially reinforced composites. They are classified mainly by the number of reinforced directions and the method in which the fibers are interwoven. Although the descriptions are thorough, many of the schemes are difficult to picture from 2D illustrations only. The manufacturing methods used to achieve these schemes are mentioned briefly, with details left to the references.
The bulk of the book concentrates on the prediction of composite stiffness and strength based on the reinforcement geometry. In general, the approach is to reduce complex 3D geometry to a 2D laminate. A family of parallel planes containing reinforcing fibers is chosen to represent the laminate. An effective anisotropic matrix is then derived based on the out-of-plane fiber geometry and actual matrix. Detailed derivations are given, but it will still help to have a good background in theoretical elasticity.
The last two chapters cover two types of specialty materials: carbon-carbon composites and whiskerized fiber composites. I found the latter to be particularly interesting. The whiskerizing process attaches small, nanoscale whiskers to traditional fibers. The resulting composites show significant increases in transverse shear strength and interlaminar shear properties.
Although the authors are Russian, the English is quite good. Many of the references, though, are in Russian. Non-Russian readers may also be unfamiliar with many of the specific materials and test methods mentioned in the book.
Because SRC was published in 1992 (and most of the refernces are from the mid-1980s or earlier), the book probably does not reflect current work in these types of composites. Still, the basic theories should not change much, so this should make a good theoretical reference for spatially reinforced composites.
Details: Spatially Reinforced Composites, by
Yu. M. Tarnopol'skii, I. G. Zhigun and V. A. Polyakov, published by
Technomic Publishing Company, 1992, ISBN 87762-679-0.
1. Types of Structural Schemes; 2. Methods for Determination of
Mechanical Properties; 3. Spatially Reinforced Media; 4. Composites
Reinforced by the System of Two Threads; 5. Composites Reinforced by
the System of Three Threads; 6. Carbon-Carbon Composites;
7. Composites Reinforced by Whiskerized Fibers; List of Symbols;
References