Introductory Chapter: Advances in Structural Health Monitoring

*Maguid H.M. Hassan*

## **1. Introduction**

Structural health monitoring has emerged as a viable tool for damage detection and preventive maintenance procedures. There is a wide range of proposed applications that were documented in the literature over the past two decades. Recently, the notion of sustainable design has emerged as an important attribute of all engineering designs. Sustainable design is defined as one that would result in systems that are smart, optimum, and reliable.

In this book, the concept of sustainable design is the backbone of the design of a structural health monitoring system. Within the backdrop of the presented definition, this book attempts to present structural health monitoring as a tool that would result in a sustainable engineering system. There are several aspects that are now being introduced to the conventional notion of structural health monitoring which are expected to contribute to such objective. Smart systems, smart materials, wireless sensor networks, conservation of historic cultural heritage, and autonomous systems are some of these aspects.

The book explores the design of smart structural health monitoring systems, using smart technologies and/or materials. It presents the issue of conservation of heritage structures using structural health monitoring tools. It explores the optimum employment of sensor networks that would render the most optimum structural health monitoring system. This book attempts to present such advanced concepts and/or technologies as the new direction of structural health monitoring.

This chapter briefly presents several advanced observations and/or applications that are considered to augment structural health monitoring techniques currently in practice.

### **2. Sustainable design**

Sustainable design is now considered an essential requirement for all engineering systems. Sustainability is introduced as a general feature that reflects a set of objectives that should be achieved within the designed system. A sustainable system is expected to be optimum, smart, reliable, and recyclable. Initially, sustainability was always related to recyclable materials that are used in constructing engineering systems. With the evolution of smart materials, the introduction of smart systems, and the innovation associated with the internet of things, sustainability should now extend to include a much wider set of objectives, as outlined above.

Structural health monitoring, which is designed to provide a mechanism for damage detection and preventive maintenance strategies, contributes to most of this set of objectives in order to attain sustainable engineering systems. Integrating structural health monitoring within engineering systems results in a smart, reliable, and optimum system, smart in the sense that the system can detect damaged components, independently, and can propose recommendations to safeguard against any potential failures; reliable in the sense that such early detection of damage and the resulting recommendations of preventive maintenance activities would directly improve the reliability of engineering systems; and finally, optimum in the sense that such integrated smart systems would result in designs that ultimately would require less materials, less maintenance, and less failure occurrences.

## **3. Smart structural health monitoring**

Structural health monitoring has gained an increased interest and research activity over the past two decades. By definition structural health monitoring comprises four main tasks, namely, damage identification, damage localization, damage severity evaluation, and structural system life expectancy prognosis. All current research activities are concentrating on the first two tasks, i.e., damage identification and localization. The continuous developments and evolutions in the applications of smart materials and technologies lend themselves to ample applications in the development of smart structural health monitoring systems.

Smart structural health monitoring systems are the ones that employ smart materials in designing their sensor networks and/or smart technologies in designing their diagnostic and inference systems. In light of the broad definition of sustainable design, presented earlier, such a smart health monitoring system, when integrated with any given structural system, would result in a sustainable engineering system.
