Chapter 1 - Introduction

Abstract

This chapter presents an overview of how the concept of structural health monitoring (SHM) could be applied to aerospace composites. Composite materials are known to have an increasing acceptance into aerospace construction over an evolutionary period that spans more than four decades. At present, the new airframes are predominantly composites, such as Boeing 787 Dreamliner and Airbus A350 XWB in which composites have 80% participation by volume (i.e., 50% participation by weight). Because the damage and failure modes of composite structures are significantly more complicated and diverse than those of metallic airframes, this widespread penetration of composite materials into commercial and military aircraft construction opens new needs for studying in-service performance, nondestructive evaluation (NDE), and SHM. Hence, the rest of the book is dedicated to understanding these intricate phenomena and identifying sensors and methods by which they can be monitored in service through the NDE and SHM processes. A review of the content of subsequent chapters is as follows. Chapter 2 is dedicated to discussing the fundamental aspects of composite materials. Chapter 3 provides the basic model for the analysis of a composite structure obtained through the lamination of several composite layers. Chapter 4 studies the stress and displacement in aerospace composites under quasi-static conditions. Chapter 5 deals with the vibration of composite structures. Chapter 6 examines ultrasonic waves in boundless anisotropic composites. Chapter 7 analyzes the existence of ultrasonic guided waves in aerospace composites. Chapter 8 covers the excitation of ultrasonic guided waves in aerospace composites. Chapter 9 discusses analytical methods for modeling guided waves in aerospace composites. Chapter 10 covers the application of stress, vibration, and wave analysis to the SHM and NDE of aerospace composites.