Presentation Transcript
Slide1 : …formulate a forward-looking collaborative research program in Integrated Structural Health Monitoring (SHM) of key civil infrastructure - a major branch of pioneering research world-wide US-China Joint Task Force On Integrated Structural Health Monitoring
A Strategic Program of US-China Research for the Next Decade US-China Joint Working Group
S.D. Glaser H. Li
M.L. Wang J. Ou
Slide2 : Comprehensive Joint Program Developed to
stimulate and guide the research community
formulate joint proposals in high priority areas
insure the common interests of both countries
leverage the resources and strengths of both countries This project has been strongly endorsed and supported by the National Science Foundation (NSF) and the National Natural Science Foundation of China (NSFC).
Slide3 : increase bi-national research in an orderly fashion
help major funding agencies to prioritize smart structures and SHM in their budget allocations. Leading Investigators From Both Countries can –
Slide5 : We Have Formulated a Comprehensive Plan to accelerate the development of integrated health monitoring of critical civil structures exposed to earthquake and wind hazards
accelerate technology transfer through complementary research and data exchanges
actively involve relevant industrial and government agencies
provide training sessions for practicing engineers
facilitate international student exchanges
design stimulating educational courses for students
Slide6 : Individual investigators and ad hoc joint research teams already exist.
China and the United States are owners of large inventories of civil structures distributed over vast areas.
Our economies are more intertwined than perhaps any other two in the world.
Common interests exist in the effective management of national infrastructure inventories.
US - driving force behind the research and development of new sensor technologies.
China - leading in deployment of sensor technologies and data interpretation for monitoring real civil structures. Synergies of a Sino-U.S. Partnership
Slide7 : JW2-3D is a newly developed tri-axial sensing device to measure three dimensional rate of acceleration change. The JW2-3D sensor relies on a coupled electro-magnetic dynamic oscillator; 1) convert analog acceleration into internal analog relative displacement; 2) rate of change of this signal sensed by coupled electro-magnetic circuitry.
Jerk has many applications: earthquake-induced structural damage detection, high-speed elevators, monitoring of train wheels (losing contact with rail), as well as global positioning
Talents from US and PRC can jointly accomplish research objectives difficult for either side alone. G. C. Lee, M. Tong, SUNY Buffalo
X. S. Yang and X. Z. Qi of IEM of CEA
supported by NSF (CMS-0414020) A New Sensor for Measuring the Rate of Change of Acceleration - JW-3D Jerk Sensor
Slide8 : Key Civil Systems and Associated Hazards.
Slide9 : Test-bed Opportunities Should be Identified and Used as Often as Possible Perhaps the most direct way to achieve these goals is to construct large-scale models in the laboratory. If we go directly to the field and instrument a complex structures, we will be at the whim of nature, waiting for the next earthquake or typhoon An ideal test-bed would be used to demonstrate -
a complete sensing network
robust wireless communications and long-lived power sources
a linked fundamental model of what constitutes damage
meaningful but solvable problems
entire networks put through their paces
hardware and software development in collaboration with all stakeholders
that proposed performance metrics capture what practicing community cares about.
Slide10 : Courtesy of Y.Q. Ni
Slide11 : Future SHM Technologies are Highly Dependent on Sensing System Model Most important enabling technology for SHM has been the Mote
comprehensive miniature sensing platforms
transduction (sensing or actuation)
signal processing
computational power
wireless communication
combinable into large, organic networks
allows dense, detailed sensing In particular, sensors and micro-circuitry made possible by micro electro-mechanical systems (MEMS) technology
Slide12 : Health Monitoring System for ZhanJiang Bay Bridge (China)
University of Illinois – Chicago
Slide13 : Lifeline systems, including energy delivery (e.g. electricity, gas, and oil), water supply and sewage pipelines, and communication systems, are essential
Little attention has been paid to systems to monitor the operating conditions of lifeline systems
Systems typically cover large areas, understanding spatially distributed sensor networks is required Sayings of the Secretary
Slide14 : Damage occurs locally, affects globally, requires dense sensing
Little work has been done on sensor fusion for the required dense sensor networks installed in civil infrastructure systems
Fundamental component of the path forward –
develop clear definition of what performance states will be considered operational (i.e. “healthy”) versus those that will be considered as “failed” (i.e. damaged) Sayings of the Secretary
Slide15 : Difficult to identify sensor technology needs without knowing where, under what measurement conditions, and for what kind of infrastructure we must contend with
Few studies have addressed both the hardware and software aspects of SHM in an integrated manner. Sayings of the Secretary
Slide16 : Ultimate Goal of SHM
facilitate rational decision-making regarding the safety and reliability of a structure
show proper actions to take when safety concerns raised.
Low-Cost Wireless Monitoring Systems : Low-Cost Wireless Monitoring Systems Collaboration between Xiamen University (Prof. Ying Lei), University of Michigan (Prof. Jerry Lynch), and Stanford University (Prof. Kincho Law)
Install a dense array of wireless sensors on the Wu-Yuan Bay Steel Arch Bridge in Xiamen Wu-Yuan Bay Bridge, Xiamen, P. R. China Installation Location of Wireless Sensors () Time-history Comparison Wired Wireless First Mode (0.78 Hz) calculated from Wireless Data
Slide18 : Damage Detection and Decision-Making Algorithms
take data collected from a monitoring system
distill out information of structure’s health state
facilitates scheduling of maintenance
initiation of damage repairs
allows rational decisions on structural retrofitting
Slide19 : Physics-Based Damage Detection
Infer the physical characteristics of a system through correlation of models and experimental input/response data
solve an inverse problem
analytical models or Green’s functions
very powerful but difficult method
Slide20 : Data-Driven Direct Damage Detection
avoids dependence on analytical models
unsupervised learning limited to level one (i.e. existence) or level two (i.e. location) damage classification
very effective for identifying the onset of damage growth
Slide21 : Statistical Damage Detection
all SHM/NDE are problems in statistical pattern recognition
damage state inferred by comparing test data with baseline data
dependence of damage diagnosis on the prior baseline data is a problem
quantify effects of imperfect sensors
Slide22 : Sensors Concepts MEMS-based devices are King! Smart materials - Research in three major areas
advancements in fabricating transducing or “self-sensing” materials
incorporating such materials into construction elements
nanoengineered materials. Active sensing and power harvesting
Usually SHM sensors are passive components
“active” sensors intentionally introduce an excitation into the structure
measures the corresponding structural response
introduce controllable and repeatable excitations
Slide23 : Sensor Transduction Technology
“Fatigue” Effect Sensors
Corrosion Effect Sensors
Optical fiber sensors
Photogrammetric Sensing Systems
Scour Effect Sensor System
Cable Force Measurement
Sensor Integration
Slide24 : Piezoelectric Paint Sensor of Ultrasonic based Damage Detection
Y. Zhang, Lehigh University, and Lily Zhou, Nanjing University of Aeronautics and Aerospace; NSF award CMS-0442076. Piezoelectric paint sample Measured ultrasonic signal at paint (tone-burst, 100 kHz) A sprayable piezoelectric paint that uniformly cures at ambient temperature. It is a composite piezoelectric material with adjustable material properties. Composite properties can be tailored to specific requirements
Applications: close-range ultrasonic based nondestructive evaluation, e.g. distributed acoustic emission sensor and ultrasonic guided wave-based embedded sensors in metal or fiber reinforced polymer composite Acoustic emission signal received by piezoelectric sensors in pencil break test
Slide25 : Historical Note - China ~ US have a long-term comprehensive research collaboration in earthquake engineering.
NSF is the American agency involved.
Chinese Agencies that have been involved include the CEA, the MOC, and the NSFC.
Unfortunately, these joint earthquake programs have had limited success.
Key problem - lack of a dedicated research program that is collectively organized by both countries.
Our view of US-China collaboration requires collective trans-Pacific organization.
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