Reliable multi-hop communication for structural health monitoring

Nagayama, Tomonori,Moinzadeh, Parya,Mechitov, Kirill,Ushita, Mitsushi,Makihata, Noritoshi,Ieiri, Masataka,Agha, Gul,Spencer, Billie F. Jr.,Fujino, Yozo,Seo, Ju-Won Techno-Press 2010 Smart Structures and Systems, An International Jou Vol.6 No.5

Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.

Reliable multi-hop communication for structural health monitoring

Tomonori Nagayama,Parya Moinzadeh,Kirill Mechitov,Mitsushi Ushita,Noritoshi Makihata,Masataka Ieiri,Gul Agha,Billie F. Spencer, Jr.,Yozo Fujino,Ju-Won Seo 국제구조공학회 2010 Smart Structures and Systems, An International Jou Vol.6 No.5

Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.

Damage identification of belt conveyor support structure using periodic and isolated local vibration modes

Amin Hornarbakhsh,Tomonori Nagayama,Shohel Rana,Tomonori Tominaga,Kazumasa Hisazumi,Ryoichi Kanno 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.3

Due to corrosion, a large number of belt conveyors support structure in industrial plants havedeteriorated. Severe corrosion may result in collapse of the structures. Therefore, practical and effectivestructural assessment techniques are needed. In this paper, damage identification methods based on twospecific local vibration modes, named periodic and isolated local vibration modes, are proposed. Theidentification methods utilize the facts that support structures have many identical members repeated alongthe belt conveyor and there exist some local modes within a small frequency range where vibrations of theseidentical members are much larger than those of the other members. When one of these identical members isdamaged, this member no longer vibrates in those modes. Instead, the member vibrates alone in an isolatedmode with a lower frequency. A damage identification method based on frequencies comparison of thesevibration modes and another method based on amplitude comparison of the periodic local vibration modeare explained. These methods do not require the baseline measurement records of undamaged structure. Themethods is capable of detecting multiple damages simultaneously. The applicability of the methods isexperimentally validated with a laboratory model and a real belt-conveyor support structure.

Damage identification of belt conveyor support structure using periodic and isolated local vibration modes

Hornarbakhsh, Amin,Nagayama, Tomonori,Rana, Shohel,Tominaga, Tomonori,Hisazumi, Kazumasa,Kanno, Ryoichi Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.3

Due to corrosion, a large number of belt conveyors support structure in industrial plants have deteriorated. Severe corrosion may result in collapse of the structures. Therefore, practical and effective structural assessment techniques are needed. In this paper, damage identification methods based on two specific local vibration modes, named periodic and isolated local vibration modes, are proposed. The identification methods utilize the facts that support structures have many identical members repeated along the belt conveyor and there exist some local modes within a small frequency range where vibrations of these identical members are much larger than those of the other members. When one of these identical members is damaged, this member no longer vibrates in those modes. Instead, the member vibrates alone in an isolated mode with a lower frequency. A damage identification method based on frequencies comparison of these vibration modes and another method based on amplitude comparison of the periodic local vibration mode are explained. These methods do not require the baseline measurement records of undamaged structure. The methods is capable of detecting multiple damages simultaneously. The applicability of the methods is experimentally validated with a laboratory model and a real belt-conveyor support structure.

Flexible smart sensor framework for autonomous structural health monitoring

Jennifer A. Rice,Kirill Mechitov,심성한,Tomonori Nagayama,Shinae Jang,Robin Kim,Billie F. Spencer, Jr.,Gul Agha,Yozo Fujino 국제구조공학회 2010 Smart Structures and Systems, An International Jou Vol.6 No.5

Wireless smart sensors enable new approaches to improve structural health monitoring (SHM) practices through the use of distributed data processing. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While much of the technology associated with smart sensors has been available for nearly a decade, there have been limited numbers of full-scale implementations due to the lack of critical hardware and software elements. This research develops a flexible wireless smart sensor framework for full-scale, autonomous SHM that integrates the necessary software and hardware while addressing key implementation requirements. The Imote2 smart sensor platform is employed, providing the computation and communication resources that support demanding sensor network applications such as SHM of civil infrastructure. A multi-metric Imote2 sensor board with onboard signal processing specifically designed for SHM applications has been designed and validated. The framework software is based on a service-oriented architecture that is modular, reusable and extensible, thus allowing engineers to more readily realize the potential of smart sensor technology. Flexible network management software combines a sleep/wake cycle for enhanced power efficiency with threshold detection for triggering network wide operations such as synchronized sensing or decentralized modal analysis. The framework developed in this research has been validated on a full-scale a cable-stayed bridge in South Korea.

Flexible smart sensor framework for autonomous structural health monitoring

Rice, Jennifer A.,Mechitov, Kirill,Sim, Sung-Han,Nagayama, Tomonori,Jang, Shinae,Kim, Robin,Spencer, Billie F. Jr.,Agha, Gul,Fujino, Yozo Techno-Press 2010 Smart Structures and Systems, An International Jou Vol.6 No.5

Wireless smart sensors enable new approaches to improve structural health monitoring (SHM) practices through the use of distributed data processing. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While much of the technology associated with smart sensors has been available for nearly a decade, there have been limited numbers of fulls-cale implementations due to the lack of critical hardware and software elements. This research develops a flexible wireless smart sensor framework for full-scale, autonomous SHM that integrates the necessary software and hardware while addressing key implementation requirements. The Imote2 smart sensor platform is employed, providing the computation and communication resources that support demanding sensor network applications such as SHM of civil infrastructure. A multi-metric Imote2 sensor board with onboard signal processing specifically designed for SHM applications has been designed and validated. The framework software is based on a service-oriented architecture that is modular, reusable and extensible, thus allowing engineers to more readily realize the potential of smart sensor technology. Flexible network management software combines a sleep/wake cycle for enhanced power efficiency with threshold detection for triggering network wide operations such as synchronized sensing or decentralized modal analysis. The framework developed in this research has been validated on a full-scale a cable-stayed bridge in South Korea.

Response based track profile estimation using observable train models with numerical and experimental validations

Jothi Saravanan Thiyagarajan,Di Su,Hirofumi Tanaka,Boyu Zhao,Tomonori Nagayama 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.2

Condition monitoring of railway tracks is essential in guaranteeing the running safety of railways. Track profiles are the primary source of external excitation for a train system. While Track Recording Vehicle is often utilized for maintenance purposes, this particular vehicle is expensive and difficult to use for small railway operators. Therefore, track profile estimation through in-service vehicle response measurements, which potentially provides efficient and frequent measurement, has been studied. However, the quantitative evaluation of the vertical and lateral track profile irregularities is still challenging as the inverse analysis solutions are sometimes inaccurate and even unstable. In this paper, numerical analyses are first carried out to evaluate track profiles from acceleration and angular velocity responses measured on a train car body. For the inverse analysis, an Augmented State Kalman Filter is utilized to solve the problem using 4 degrees of freedom observable train models. The sensor installation locations are investigated through observability rank condition analysis with different measurement layout. Secondly, a field experiment is carried out in a local Japanese in-service railway network to estimate track profile from car body motions. Smartphones are utilized for the field test measurements as prevalent sensing devices. The effectiveness of the proposed approach is demonstrated with the observable train model. Numerical analyses and field experiments clarify the proposed track profile estimation’s capability using only one on-board sensing device.

Synchronized sensing for wireless monitoring of large structures

Robin E. Kim,Jian Li,Billie F. Spencer, Jr,Tomonori Nagayama,Kirill A. Mechitov 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.5

Advances in low-cost wireless sensing have made instrumentation of large civil infrastructure systems with dense arrays of wireless sensors possible. A critical issue with regard to effective use of the information harvested from these sensors is synchronized sensing. Although a number of synchronization methods have been developed, most provide only clock synchronization. Synchronized sensing requires not only clock synchronization among wireless nodes, but also synchronization of the data. Existing synchronization protocols are generally limited to networks of modest size in which all sensor nodes are within a limited distance from a central base station. The scale of civil infrastructure is often too large to be covered by a single wireless sensor network. Multiple independent networks have been installed, and post-facto synchronization schemes have been developed and applied with some success. In this paper, we present a new approach to achieving synchronized sensing among multiple networks using the Pulse-Per-Second signals from low-cost GPS receivers. The method is implemented and verified on the Imote2 sensor platform using TinyOS to achieve 50 us synchronization accuracy of the measured data for multiple networks. These results demonstrate that the proposed approach is highly-scalable, realizing precise synchronized sensing that is necessary for effective structural health monitoring.

Smart Wireless Sensor Technology for Structural Health Monitoring of Civil Structures

조수진,윤정방,Jerome P. Lynch,Andrew T. Zimmerman,Billie F. Spencer Jr,Tomonori Nagayama 한국강구조학회 2008 International Journal of Steel Structures Vol.8 No.4

This paper presents the results of international cooperative researches on smart wireless sensors and SHM of civil structures among KAIST, the University of Michigan, and the University of Illinois at Urbana-Champaign. At first, the state-of-art in the smart wireless sensor technology is reviewed. The subsystems of a smart wireless sensor are discussed, and available wireless sensor platforms developed in the academia and industries are reviewed. Then three smart wireless SHM systems developed by the present authors are applied to SHM of various types of civil structures in this study. The first example is a distributed modal identification system using a smart wireless sensor platform, which is applied to the modal identification of a balcony structure in a historic theatre. The second one is a low-cost and autonomous wireless tension estimation system for cable-stayed bridges, which is employed for modal identification and tension estimation of a stay cable. The last one is an autonomous decentralized SHM system, which is applied to damage detection on a 3-D steel truss structure.