Title: Sensing Platforms for Structural Health Management: Recent Developments and Future Opportunities
Speaker: Prof. Sridhar Krishnaswamy (Northwestern University, USA)
Time: Jan.19,2015, 9:00AM
Venue: No. 101 Meeting Room, IOS, CAS
Abstract: Integrated Structural Health Management (ISHM) is an emerging concept that provides an efficient methodology to minimize the possibility of catastrophic failure of safety-critical structures. ISHM comprises diagnostic and prognostic modules as shown in the figure. ISHM relies on extensive onboard diagnostic sensors that can provide near real-time information about the state of a structure so that informed prognostic assessment can be made of the continuing reliability of the structure. Structures with integrated sensing capabilities are referred to as “smart structures”. In this talk, I will discuss two types of sensing platforms that can be integrated into a smart structure: 1D fiber-optic sensors and 2D thin-film sensors. Both fiber-optic and thin film sensors are easily integrated with structures, and can offer local and/or distributed sensing capabilities. Parameters that can be sensed include: static and dynamic strain, acoustic emission, vibration, corrosion products, moisture ingression etc. I will first describe some recent developments in dynamic strain sensing using optical Fiber Bragg grating (FBG) sensors. Applications to detection of acoustic emission and impact will be described. In the area of chemical sensing, I will describe a nanofilm-coated photonic crystal fiber (PCF) long-period grating (LPG) sensing platform. PCF-LPG sensors can be designed to provide greater interaction between the analyte of interest and the light propagating in the fiber. One type of sensor we have been fabricating is based on reduced graphene oxide for large-area chemical sensing applications. It is expected that these 1D and 2D sensing platforms will form part of a suite of sensors that can provide diagnostic structural health information.
I will conclude by discussing some opportunities in terms of sensor miniaturization and sensor robustness where the photonics and micro-electronics communities can play a significant role in the area of smart structures.
Biography： Sridhar Krishnaswamy obtained his BTech from the Indian Institute of Technology, Madras, and his M.S. and PhD in Aeronautics from the California Institute of Technology. He joined the faculty at Northwestern University in 1990 where he is currently a full Professor of Mechanical Engineering and Director of the Center for Quality Engineering and Failure Prevention.
Prof. Krishnaswamy’s research interests are in multifunctional materials, optical and thin film sensors as applied to smart structures, and nondestructive methods of materials characterization. He has published over 200 technical articles, and holds one patent. His research has been sponsored to the tune of over US$11M over the past two decades by several federal agencies including the US National Science Foundation, the Air Force Office of Sponsored Research, the Office of Naval Research, the Federal Aviation Administration, the Department of Transportation etc., and industry such as GE, Caterpillar and Honeywell etc. Over the years, he has developed extensive research collaborations with organizations across the globe, particularly in China, India, Korea and Europe.
Prof. Krishnaswamy is a Fellow of ASME and SPIE.