Preface

Functionally graded materials (FGMs) are composite materials, microscopically inhomoge‐ neous, in which the mechanical properties vary smoothly and continuously from one sur‐ face to the other. This is achieved by gradually varying the volume fraction of the constituent materials. An FGM is a two-component composite characterized by a composi‐ tional gradient from one component to the other. The properties of both components can be fully utilized. For example, the toughness of a metal can be mated with the refractoriness of a ceramic, without any compromise in the toughness of the metal side or the refractoriness of the ceramic side. FGMs were initially designed as thermal barrier materials for aerospace structures and fusion reactors and now they are also considered as potential structural mate‐ rials for future high-speed spacecraft and now are being increasingly considered in various applications to maximize strengths and integrities of many engineering structures.

This book is a result of contributions of experts from international scientific community working in different aspects of FGMs and structures and reports on the state of the art re‐ search and development findings on this topic through original and innovative research studies. Through its six chapters, the reader will have access to works related to processing, sintering properties and applications of functionally graded ceramics and new processing routes for FGMs while it introduces some specific applications, such as functionally graded annular fins and the high-performance self-lubricating ceramic composites with laminated graded structure. Besides, it presents an experimental crack propagation analysis of alumi‐ num matrix FGMs and a unified accurate solution for three-dimensional vibration analysis of functionally graded plates and cylindrical shells with general boundary conditions.

The book contains up-to-date publications of leading experts, and the edition is intended to furnish valuable recent information to the professionals involved in functionally graded ma‐ terials and structure analysis and applications. The text is addressed not only to researchers but also to professional engineers, students and other experts in a variety of disciplines, both academic and industrial, seeking to gain a better understanding of what has been done in the field recently, and what kind of open problems are in this area.

I hope that readers will find the book useful and inspiring by examining the recent develop‐ ments in FGMs and structures.

Lastly, I would like to thank all the authors for their excellent contributions in different areas covered by this book, and the InTech team, especially the process manager Ms. Iva Lipović, for their support and patience during the whole process of creating this book.

> **Dr. Farzad Ebrahimi** Department of Mechanical Engineering, Imam Khomeini International University, Qazvin, Iran
