Perturbation Methods for Damaged Structures. Back Matter Pages About this book Introduction The increased level of activity on structural health monitoring SHM in various universities and research labs has resulted in the development of new methodologies for both identifying the existing damage in structures and predicting the onset of damage that may occur during service. About the authors Dr S.
He specializes in the areas of structural health monitoring, wave propagation, smart structures and computational mechanics. He has authored four books, journal papers, eight book chapters, and over 70 conference papers. He is on the editorial board of six international journals and the Associate Editor for two international journals, namely, the International Journal of Smart Materials and Structures, and Structural Health Monitoring.
Ruzzene conducts research in the broad areas of structural dynamics and wave propagation, non-destructive evaluation techniques, modal analysis and structural acoustics. He is the author of six book chapters two on structural health monitoring , more than 85 journal papers and more than conference papers. He serves as a reviewer for several journals, and as an associate editor of the Journal of Vibrations and Acoustics and of Mechanics Research Communications.
He became a tenure track faculty member in He taught at the University of Santa Clara as an adjunct faculty member from through Prior to receiving his PhD, he was a research assistant at Stanford University and a research fellow at the Indian Institute of Science. Active and passive sensors are used to capture data and are evaluated with the help of special computer system along with software like Arc GIS. In the conventional SHM system, the expensive cost for purchase and installation of the SHM system components, such as sensors, data loggers, computers, and connecting cables, is a big obstruction.
To guarantee that measurement data are reliably collected, SHM systems generally employ coaxial wires for communication between sensors and the repository. However, the installation of coaxial wires in structures is generally very expensive and labor-intensive [16]. Wireless techniques are mainly associated with to find out the ground information like land use and land cover, possible urban area, solid waste disposal site selection, possible best way for roads etc.
Ramanjaneyulu Smart Wireless Technology Smart wireless sensor is an emerging sensor with the following essential features: on-board micro-processor, sensing capability, wireless communication, battery powered, and low cost Nagayama, When many sensors are implemented on a SHM system for a sizable civil structure, wireless communication between sensors and data repository seems to be attractive in the aspects of the cost [16].
For the improvement in SHM techniques, new sensors are developed. Different sensors system like Micro- electromechanical system MEMS , Nuclear magnetic resonance NMR for accelerometers and to detect chloride ions are used for the detection of defects [17, 18].
These sensors are typically targeted to monitor specific defect like concrete cracking, bridge breaking, and steel reinforcement corrosion [17], this is one major defect of wireless technique. For e. Revolution on wired technique invents wireless smart sensors hence find new solution for economical aspect. Radar technology, robust techniques largely depends on the incident rays, absorbed, transmitted and reflected rays.
Robust technique uses X-rays and gamma-rays to get visual images of interiors of structures such as steel cables, slabs etc. Increase in research due to challenging environment, different techniques comes into practice in civil, mechanical, aerospace field.
Straser and Kiremidjian, first proposed a design of a low-cost wireless modular monitoring system WiMMS for civil structures by integrating a microcontroller with a wireless radio. Lynch et al. And in present damage detection reported to the base station in sleeping mode [17] which was shown in figure. Hence through variation of the data finally gives clue to detect risky zone or detect zone.
Ramanjaneyulu The component on wired as well as in Wireless Techniques are almost same but only difference is position of sensor, but overall theme is to monitor the health of structure.
SHM is not limited within civil engineering. Its application field increases its demand. Due to age factor and environment factor, Structure gets deteriorated and steel structures got corroded. Due to that reason, structures strength decreases regarding serviceability and load bearing approach. For detecting it several techniques investigated and researchers still doing for up gradation. Although SHM techniques can be used in several structure like beam [22] shell [23] and in pipeline also.
Using those techniques on such a structure enhances to up gradation for the effective efficiency as well as secure public service. Due to increasing cost for inspection and the demand of periodic investigation of defect on the structure, previous maintenance concept of periodic inspection is no longer in use. Thus present SHM techniques is seeking the use of intelligent powerful data acquisition unit and a fast and direct monitoring and maintenance planning concept is required [24].
Different types of structural health monitoring techniques have their own advantage and limitations. As a technician, we have to look for cost effective, precise and accurate methods. The state of structural system subjected to those physical and climatic processes is changing continuously.
The condition of the structure may not predict without considering both aleatory and epistemic uncertainties. So, it is possible if we monitor structure in periodic sequence, through it we have to consider the techniques which give standard and believable result in terms of structural integrity and economic approach [25] Uses of vibration control techniques, impedance based approach leads higher cost and for periodic monitoring installation charge may add up but through these techniques we can get accurate result.
Sensors can be used for various materials. It is old techniques, which gives bases for further innovation This is emerging new technique in which, Sensed data is recorded of sensors, and detecting technology.
Little bit Costly techniques because if we need to detect, we Initial cost is higher but in life time analysis, cost becomes less and have to install is periodically. Data Fusion techniques Used principle in this technique is same as in Impedance based approach but in this process of integrating data and knowledge representing the same real world object in consistent, accurate, and useful representation. Vibration Control Technique Mostly used technique from ancient time, is depends on Vibration applied from the sensors, Damping, and signature getting from system.
Care should be taken in it, due to vibration structure may further damage. It is continuous or periodic monitoring used in wireless and wired technology. In this echo of sound is measured.
Smart sensors wireless technology Recent development and applications of smart sensors and sensing systems have a wide area of structural health monitoring including Optical Fiber Sensors OFS , piezoelectric sensors, smart wireless sensors, and vision-based displacement measurement systems.
They have been developed to complement the limitations of the conventional sensors such as electric resistance strain gauges, wired accelerometers, and extensometers, and to measure new types of structural characteristics such as electromechanical impedances and guided waves [25] Many Research are doing corresponding to Wireless smart sensing system for full scale structure. By this damage index we can able to compare the difference of healthy and damaged structure.
RESULTS The established SHM have proven the well defined effort on the sustainability and safety of the structure and have forecasted the greater possibility in monitoring and control of structural damage and reduce the incidental loss of lives making the SHM necessary in the life structures like Bridge and Towers. By reviewing journals of SHM, the fact found is four step processes 1 Operational evaluation 2 Data acquisition, normalization and cleansing 3 Feature selection and information consideration and 4 Statistical model development for the feature determination is common for all the techniques [13].
By following these steps, apart from simple structure such as axial rods [27], beams [22], thin plates [28], shell [23] and framed structure [29], experimental implementation of the SHM techniques can be applied on several complex structures.
In present Days Structural health monitoring techniques for Pipeline are in the research phase for getting higher efficiency to damage detection. Ramanjaneyulu Talking about the efficiency that sensors can give the data for probable damage detection is much concern about the number, area covered by sensor and the type of material that structure is built. For choosing the SHM techniques first its need to collect the features like material used, efficiency required and area that need to be sensed of structure has to be noted and the cast outflow for the corresponding work should be determined.
Wired techniques seems to be used in large scale than wireless techniques because of its popularity and its efficiency, among wired technique Vibration based approach and acoustic emission approach more commonly used than wireless techniques.
Whatever the methods and systems that are discussed above speaks the requirement of regular inspection and use of expensive instruments in the detection and identification of the damage in the structures. So there is need of cost effective and more efficient techniques in SHM for its revolutionary implementation and make the world better. Remarkable improvement on the sensors like one sensor can be used for different materials is needed.
For periodic monitoring, wired techniques have a difficult for installation and hence such kind of system is needed though which we can monitor structure in regular time interval. From the review of different techniques, newly emerging wireless techniques have a more scope in terms of economic aspects, time constraint and easiness although several research are carried out in both the methods and remarkable diminutive amendments on the system, software algorithm was found.
Still if we do research for a SHM like as remote sensing, for it higher resolution image is needed and it will add up new resolution in from all aspects of life time assessment.
Indeed SHM systems are more important day by day especially on public structures like Bridge, Towers, Transportation means for the human safety and environmental sustainability approach too. Peter C. Chang, Alison Flatau and S. Dawson, Brian Authors : I. Takewaki, Kyoto University, Japan; M. Yoshitomi, Kyoto University, Japan. Increase in the demand for reliable structural health information led to the development of Structural Health Monitoring SHM.
Prediction of upcoming accidents and estimation of useful life span of a structure are facilitated through SHM. While data sensing is the core of any SHM, tracking the data anytime anywhere is a prevailing challenge. With the advancement in information technology, the concept of Internet of Things IoT has made it possible to integrate SHM with Internet to track data anytime anywhere. In this paper, a SHM platform embedded with IoT is proposed to detect the size and location of damage in structures.
The piezoelectric sensors are mounted as a pair in the structure. Data collected from the piezoelectric sensors will be used to detect the size and location of damage using a proposed mathematical model.
The increased level of activity on structural health monitoring SHM in various universities and research labs has resulted in the development of new methodologies for both identifying the existing damage in structures and predicting the onset of damage that may occur during service. Designers often have to consult a variety of textbooks, journal papers and reports, because many of these methodologies require advanced knowledge of mechanics, dynamics, wave propagation, and material science.
Computational Techniques for Structural Health Monitoring gives a one-volume, in-depth introduction to the different computational methodologies available for rapid detection of flaws in structures. Techniques, algorithms and results are presented in a way that allows their direct application. A number of case studies are included to highlight further the practical aspects of the selected topics.
Computational Techniques for Structural Health Monitoring also provides the reader with numerical simulation tools that are essential to the development of novel algorithms for the interpretation of experimental measurements, and for the identification of damage and its characterization. Structural Health Monitoring of Aerospace Composite Structures offers a comprehensive review of established and promising technologies under development in the emerging area of structural health monitoring SHM of aerospace composite structures.
Beginning with a description of the different types of composite damage, which differ fundamentally from the damage states encountered in metallic airframes, the book moves on to describe the SHM methods and sensors currently under consideration before considering application examples related to specific composites, SHM sensors, and detection methods.
Expert author Victor Giurgiutiu closes with a valuable discussion of the advantages and limitations of various sensors and methods, helping you to make informed choices in your structure research and development. Aerospace engineers, researchers and graduate students dealing with aircraft design, structural integrity, safety and operation management.
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