New passive defect detection technique

Abstract

This paper discusses the development of a new passive technique of online damage detection based on the most fundamental concept in continuum mechanics – strain compatibility. The main feature of this method is its invariance to changing loading conditions. The technique is quite general, and can be applied to structures made of isotropic or anisotropic materials and structural components experiencing elastic or plastic deformations. The detection of an edge crack utilising this technique is considered in this paper and demonstrates a good potential of this method for many practical applications.

Keywords:

• Crack detection
• continuum mechanics
• distributed dislocation technique
• edge crack
• finite difference
• non-destructive evaluation technique
• strain compatibility
• structural health monitoring.

Additional information

Notes on contributors

S Wildy

Stuart Wildy graduated with honours from the University of Adelaide with a Bachelor of Engineering (Mechatronics) in 2006 and is currently completing a PhD in Engineering at the same institution. His research involves investigating new techniques for detecting damage, such as cracks and delamination, in plate and shell-like structures. His other research interests include structural health monitoring, experimental stress analysis, non-destructive testing, fracture mechanics and composite materials. Some of the projects he is currently involved in include Measuring Deflection in Aerospace Structures (sponsored by the DSTO), research work for the Australia Submarine Corporation, and the development and investigation of a slurry spray based method for thermal barrier coatings (sponsored through the Asian Office of Aerospace Research and Development). At the University of Adelaide he is actively involved with teaching and tutoring undergraduate students in subjects such as stress analysis and design, solid mechanics, and fracture mechanics. In 2007 Stuart won an award at the Australian Congress of Applied Mechanics for the best student poster for his presentation titled “Monitoring of Crack Propagation Using a Cluster of Piezo-sensors”. He is also a member of Engineers Australia.

A Kotousov

Dr Andrei Kotousov completed his PhD study at the Russian Academy of Sciences in 1993, and is currently Senior Lecturer at the School of Mechanical Engineering, University of Adelaide. He teaches the Solid Mechanics, Fracture Mechanics, and Stresses in Plates and Shells courses at the School, supervises PhD and Master Degree Students, and is actively involved into a number of large research projects.

Andrei has broad experience in theoretical and experimental fracture mechanics, biomechanics, structural health monitoring and composite materials, having produced more than 100 peer reviewed publications in these areas. He also serves as a regular reviewer for international journals, conferences, and national and international grant applications.

J Codrington

John Codrington completed his Bachelor of Engineering (Mechanical) with honours at the University of Adelaide in 2005, and is currently studying for a PhD at the same institution. John received an Australian Postgraduate Award for his studies into non-linear individual and interaction phenomena in fatigue crack growth. General research interests include fracture mechanics, fatigue, structural health monitoring, biomechanics and composites. Some current projects that John is involved with include the development and investigation of a slurry spray based method for thermal barrier coatings (sponsored through the Asian Office of Aerospace Research and Development), the development of a new strain compatibility based method for crack detection and consultant work for ASC.