Structural Health Monitoring (SHM) in Aerospace Structures

Fuh-Gwo Yuan

• Publisher: Woodhead Publishing
• Year: 2016
• ISBN:
  9780081001585
• Topic: Technology & Engineering
• Subtopic: Aeronautic & Astronautic Engineering
• Index: Technology & Engineering

Structural Health Monitoring (SHM) in Aerospace Structures provides readers with the spectacular progress that has taken place over the last twenty years with respect to the area of Structural Health Monitoring (SHM). The widespread adoption of SHM could both significantly improve safety and reduce maintenance and repair expenses that are estimated to be about a quarter of an aircraft fleet's operating costs.

The SHM field encompasses transdisciplinary areas, including smart materials, sensors and actuators, damage diagnosis and prognosis, signal and image processing algorithms, wireless intelligent sensing, data fusion, and energy harvesting. This book focuses on how SHM techniques are applied to aircraft structures with particular emphasis on composite materials, and is divided into four main parts.

Part One provides an overview of SHM technologies for damage detection, diagnosis, and prognosis in aerospace structures. Part Two moves on to analyze smart materials for SHM in aerospace structures, such as piezoelectric materials, optical fibers, and flexoelectricity. In addition, this also includes two vibration-based energy harvesting techniques for powering wireless sensors based on piezoelectric electromechanical coupling and diamagnetic levitation. Part Three explores innovative SHM technologies for damage diagnosis in aerospace structures. Chapters within this section include sparse array imaging techniques and phase array techniques for damage detection. The final section of the volume details innovative SHM technologies for damage prognosis in aerospace structures.

This book serves as a key reference for researchers working within this industry, academic, and government research agencies developing new systems for the SHM of aerospace structures and materials scientists.

• Provides key information on the potential of SHM in reducing maintenance and repair costs
• Analyzes current SHM technologies and sensing systems, highlighting the innovation in each area
• Encompasses chapters on smart materials such as electroactive polymers and optical fibers

Part One

SHM technologies for damage detection, diagnosis and prognosis in aerospace structures: application and efficient use

Outline

1. Integrated vehicle health management in aerospace structures

2. A novel approach for implementing structural health monitoring systems for aerospace structures

1

Integrated vehicle health management in aerospace structures

R.W. Ross NASA Langley Research Center, Hampton, VA, United States

Abstract

To meet the expected increase in demand for air and space transportation over the next several decades, new technologies will be needed to sustain the safe and efficient operation of these vehicles. Structural health monitoring and inspection methods allow early detection of damage or degradation to critical components, enabling corrective action can be taken so vehicle components can safely and economically perform their intended function. Integrated vehicle health management allows current and future vehicles to safely and efficiently operate in harsh environments and to meet operational requirements. Probabilistic health assessment and predictive modeling methods allow the safe and efficient design and operation of aerospace vehicles without being overly conservative. Combining predictive models with continuous health monitoring assures decision-makers that these models accurately reflect the state of a vehicle over its entire lifetime, allowing simulation-based systems engineering models to be used as an effective tool for ensuring mission success.

Keywords

Digital twin; Integrated vehicle health management; Prognostics; Simulation-based systems engineering; Structural health monitoring

1.1. Introduction

Structural health monitoring (SHM) facilitates the detection and characterization of damage to a structure or component that may result in its ability to fully and safely perform its intended function. Farrar and Worden (2007) defined damage as “changes introduced into a system that adversely affect its current or future performance.” The goal of SHM is to identify these changes at the earliest possible opportunity so that corrective action can be taken to minimize downtime, operational costs, and maintenance costs, and to reduce the risk of catastrophic failure, injury, or even loss of life.

SHM and its related health management technologies have played an important role in protecting machinery and vehicle components from performance degradation and failure, and future technologies will likely extend these capabilities to highly complex vehicles and systems. Health management technologies will continue to evolve in intelligence from the simple measurement and test equipment of past decades to highly intelligent systems capable of making decisions based on predictions of future performance and remaining life. Different terminology has been applied to these technologies, reflecting their level of maturity and scope, as well as their degree of capability, intelligence, and automation, as shown in Fig. 1.1. This section discusses these technologies and their contributions to health management.

Historically, condition monitoring (CM), which is closely associated with SHM, has been widely and successfully used to diagnose malfunctions and damage to rotating and reciprocating machinery at regular intervals (Bently and Hatch, 2003). Use of CM for these applications was highly successful for three reasons. First, the equipment being monitored is typically operated in a consistent manner under well-known operating and environmental conditions. Second, large quantities of data are readily available for both nominal and off-nominal conditions, and failure modes are well understood. Lastly, there is a strong and well-defined financial incentive to provide CM.

Despite the success of CM for rotating and reciprocating machineries, in many other applications health monitoring technologies have been less successful. One such application is SHM for health monitoring of transportation vehicles and systems, including both aerospace and automotive vehicles. These vehicles operate under a wide spectrum of environmental and operational conditions in a changing and often unpredictable manner, making it extremely difficult to identify all nominal and off-nominal operating scenarios. Consequently, it is much more difficult to definitively identify damage under these conditions, possibly resulting in false indications of damage. Because of the complexity of the problem, and without strong confidence in the accuracy of the diagnosis, the economic benefits of SHM are equally difficult to quantify.

Figure 1.1 Terminology for current and future health management technologies reflects advances in evolution and intelligence.

Despite these challenges, the structural health community has made significant progress to date, although much work remains to be done. Many researchers and organizations have focused on addressing particular aspects of SHM, and their definitions of SHM reflect the diversity of these focus areas. The G-11 SHM committee for Structural Health Monitoring and Management, Aerospace Industry Steering Committee, addresses the need for reliable sensor measurement and damage diagnosis, defining SHM as “the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure” (SAE International, 2013).

Farrar and Worden (2007) emphasized the importance of feature analysis, as reflected in their definition of SHM as “the observation of a structure or mechanical system over time using periodically spaced measurements, the extraction of damage-sensitive features from these measurements, and the statistical analysis of these features to determine the current state of health.”

The National Aeronautics and Space Administration (NASA) addressed the operational aspects of SHM, focusing not only on the consequences of loss of structural integrity but also on the impact on safety and performance of aerospace vehicles due to damage or degradation. NASA researchers (Seshadri et al., 2014) define structural health management as “a continuous assessment of structural integrity to increase safety and performance within design constraints to meet operational requirements.” NASA uses SHM for safe and efficient operation of space vehicles to meet mission objectives.

Integrated vehicle health management (IVHM) and integrated systems health management (ISHM) extend the health monitoring concept ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles
• Copyright
• List of contributors
• Woodhead Publishing Series in Composites Science and Engineering
• Preface
• Part One. SHM technologies for damage detection, diagnosis and prognosis in aerospace structures: application and efficient use
• Part Two. Smart materials for SHM in aerospace structures
• Part Three. Innovative SHM technologies for damage diagnosis in aerospace structures
• Part Four. Innovative SHM technologies for damage prognosis in aerospace structures
• Index