Sensor enriched infrastructure system

Ming L. Wang,임진석 국제구조공학회 2010 Smart Structures and Systems, An International Jou Vol.6 No.3

Civil infrastructure, in both its construction and maintenance, represents the largest societal investment in this country, outside of the health care industry. Despite being the lifeline of US commerce, civil infrastructure has scarcely benefited from the latest sensor technological advances. Our future should focus on harnessing these technologies to enhance the robustness, longevity and economic viability of this vast, societal investment, in light of inherent uncertainties and their exposure to service and even extreme loadings. One of the principal means of insuring the robustness and longevity of infrastructure is to strategically deploy smart sensors in them. Therefore, the objective is to develop novel, durable, smart sensors that are especially applicable to major infrastructure and the facilities to validate their reliability and long-term functionality. In some cases, this implies the development of new sensing elements themselves, while in other cases involves innovative packaging and use of existing sensor technologies. In either case, a parallel focus will be the integration and networking of these smart sensing elements for reliable data acquisition, transmission, and fusion, within a decision-making framework targeting efficient management and maintenance of infrastructure systems. In this paper, prudent and viable sensor and health monitoring technologies have been developed and used in several large structural systems. Discussion will also include several practical bridge health monitoring applications including their design, construction, and operation of the systems.

The utilities of U-shape EM sensor in stress monitoring

Wang, Guodun,Wang, Ming L. Techno-Press 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.17 No.3

In this paper, load monitoring technologies using U-shape Magnetoelastic (EM or ME) sensors have been exploited systemically for the first time. The steel rod to be tested is the Japan 7 mm piano steel rod. The load dependence of the magnetic properties of the piano steel rod was manifested. Two experimental designs of U-shape magnetoelastic sensors were introduced, one with double pick-up concentric coils wound on the rod to be tested, the other with pick-up coil on one yoke foot. The former design is used to derive the correlation of the relative permeability with elastic tension, while the latter is aimed to reflect the stress induced magnetic flux variation along the magnetic circuit. Magnetostatic simulations provide interpretations for the yoke foot sensing technology. Tests with double pick-up coils indicate that under proper working points (primary voltages), the relative permeability varies linearly with the axial load for the Japan 7 mm piano steel rod. Tests with pick-up coil on the yoke foot show that the integrated sensing voltage changes quadratically with the load, and error is more acceptable when the working point is high enough.

Sensor enriched infrastructure system

Wang, Ming L.,Yim, Jinsuk Techno-Press 2010 Smart Structures and Systems, An International Jou Vol.6 No.3

Civil infrastructure, in both its construction and maintenance, represents the largest societal investment in this country, outside of the health care industry. Despite being the lifeline of US commerce, civil infrastructure has scarcely benefited from the latest sensor technological advances. Our future should focus on harnessing these technologies to enhance the robustness, longevity and economic viability of this vast, societal investment, in light of inherent uncertainties and their exposure to service and even extreme loadings. One of the principal means of insuring the robustness and longevity of infrastructure is to strategically deploy smart sensors in them. Therefore, the objective is to develop novel, durable, smart sensors that are especially applicable to major infrastructure and the facilities to validate their reliability and long-term functionality. In some cases, this implies the development of new sensing elements themselves, while in other cases involves innovative packaging and use of existing sensor technologies. In either case, a parallel focus will be the integration and networking of these smart sensing elements for reliable data acquisition, transmission, and fusion, within a decision-making framework targeting efficient management and maintenance of infrastructure systems. In this paper, prudent and viable sensor and health monitoring technologies have been developed and used in several large structural systems. Discussion will also include several practical bridge health monitoring applications including their design, construction, and operation of the systems.

Long term health monitoring of post-tensioning box girder bridges

Wang, Ming L. Techno-Press 2008 Smart Structures and Systems, An International Jou Vol.4 No.6

A number of efforts had been sought to instrument bridges for the purpose of structural monitoring and assessment. The outcome of these efforts, as gauged by advances in the understanding of the definition of structural damage and their role in sensor selection as well as in the design of cost and data-effective monitoring systems, has itself been difficult to assess. The authors' experience with the design, calibration, and operation of a monitoring system for the Kishwaukee Bridge in Illinois has provided several lessons that bear upon these concerns. The systems have performed well in providing a continuous, low-cost monitoring platform for bridge engineers with immediate relevant information.

Results and implications of the damage index method applied to a multi-span continuous segmental prestressed concrete bridge

Wang, Ming L.,Xu, Fan L.,Lloyd, George M. Techno-Press 2000 Structural Engineering and Mechanics, An Int'l Jou Vol.10 No.1

Identification of damage location based on modal measurement is an important problem in structural health monitoring. The damage index method that attempts to evaluate the changes in modal strain energy distribution has been found to be effective under certain circumstances. In this paper two damage index methods using bending strain energy and shear strain energy have been evaluated for numerous cases at different locations and degrees of damage. The objective is to evaluate the feasibility of the damage index method to localize the damage on large span concrete bridge. Finite element models were used as the test structures. Finally this method was used to predict the damage location in an actual structure, using the results of a modal survey from a large concrete bridge.

Application of magnetoelastic stress sensors in large steel cables

Wang, Guodun,Wang, Ming L.,Zhao, Yang,Chen, Yong,Sun, Bingnan Techno-Press 2006 Smart Structures and Systems, An International Jou Vol.2 No.2

In this paper, the application of magnetoelasticity in static tension monitoring for large steel cables is discussed. Magnetoelastic (EM) stress sensors make contact-free tension monitoring possible for hanger cables and post-tensioned cables on suspension and cable-stayed bridges. By quantifying the correlation of magnetic relative permeability with tension and temperature, the EM sensors inspect the load levels in the steel cables. Cable tension monitoring on Qiangjiang (QJ) 4th Bridge demonstrates the reliability of the EM sensors.

Application of magnetoelastic stress sensors in large steel cables

Guodun Wang,Ming L. Wang,Yang Zhao,Yong Chen,Bingnan Sun 국제구조공학회 2006 Smart Structures and Systems, An International Jou Vol.2 No.2

In this paper, the application of magnetoelasticity in static tension monitoring for large steel cables is discussed. Magnetoelastic (EM) stress sensors make contact-free tension monitoring possible for hanger cables and post-tensioned cables on suspension and cable-stayed bridges. By quantifying the correlation of magnetic relative permeability with tension and temperature, the EM sensors inspect the load levels in the steel cables. Cable tension monitoring on Qiangjiang (QJ) 4th Bridge demonstrates the reliability of the EM sensors.

Field application of elasto-magnetic stress sensors for monitoring of cable tension force in cable-stayed bridges

임진석,신성우,Ming L. Wang,윤정방,정형조,김정태,음승현 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.12 No.4

Recently, a novel stress sensor, which utilizes the elasto-magnetic (EM) effect of ferromagnetic materials, has been developed to measure stress in steel cables and wires. In this study, the effectiveness of this EM based stress sensors for monitoring of the cable tension force of a real scale cable-stayed bridge was investigated. Two EM stress sensors were installed on two selected multi-strand cables in Hwa-Myung Bridge, Busan, South Korea. Conventional lift-off test was conducted to obtain reference cable tension forces of two test cables. The reference forces were used to calibrate and validate cable tension force measurements from the EM sensors. Tension force variations of two test cables during the second tensioning work on Hwa-Myung Bridge were monitored using the EM sensors. Numerical simulations were conducted to compare and verify the monitoring results. Based on the results, the effectiveness of EM sensors for accurate field monitoring of the cable tension force of cable-stayed bridge is discussed.

Field application of elasto-magnetic stress sensors for monitoring of cable tension force in cable-stayed bridges

Yim, Jinsuk,Wang, Ming L.,Shin, Sung Woo,Yun, Chung-Bang,Jung, Hyung-Jo,Kim, Jeong-Tae,Eem, Seung-Hyun Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.12 No.3

Recently, a novel stress sensor, which utilizes the elasto-magnetic (EM) effect of ferromagnetic materials, has been developed to measure stress in steel cables and wires. In this study, the effectiveness of this EM based stress sensors for monitoring of the cable tension force of a real scale cable-stayed bridge was investigated. Two EM stress sensors were installed on two selected multi-strand cables in Hwa-Myung Bridge, Busan, South Korea. Conventional lift-off test was conducted to obtain reference cable tension forces of two test cables. The reference forces were used to calibrate and validate cable tension force measurements from the EM sensors. Tension force variations of two test cables during the second tensioning work on Hwa-Myung Bridge were monitored using the EM sensors. Numerical simulations were conducted to compare and verify the monitoring results. Based on the results, the effectiveness of EM sensors for accurate field monitoring of the cable tension force of cable-stayed bridge is discussed.

DNA-functionalized single-walled carbon nanotube-based sensor array for gas monitoring

Wenjun Zhang,Yu Liu,Ming. L Wang 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.12 No.1

Nine deoxyribonucleic acid (DNA) sequences were used to functionalize single-walled carbon nanotube (SWNT) sensors to detect the trace amount of methanol, acetone, and HCl in vapor. DNA 24 Ma (24 randomly arranged nitrogenous bases with one amine at each end of it) decorated SWNT sensor and DNA 24 A (only adenine (A) base with a length of 24) decorated SWNT sensor have demonstrated the largest sensing responses towards acetone and HCl, respectively. On the other hand, for the DNA GT decorated SWNT sensors with different sequence lengths, the optimum DNA sequence length for acetone and HCl sensing is 32 and 8, separately. The detection of methanol, acetone, and HCl have identified that DNA functionalized SWNT sensors exhibit great selectivity, sensitivity, and repeatability with an accuracy of more than 90%. Further, a sensor array composed of SWNT functionalized with various DNA sequences was utilized to identify acetone and HCl through pattern recognition. The sensor array is a combination of four different DNA functionalized SWNT sensors and two bare SWNT sensors (work as reference). This wireless sensing system has enabled real-time gas monitoring and air quality assurance for safety and security.