Decentralized energy market-based structural control

Lynch, Jerome Peter,Law, Kincho H. Techno-Press 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.17 No.3

Control systems are used to limit structural lateral deflections during large external loads such as winds and earthquakes. Most recently, the semi-active control approach has grown in popularity due to inexpensive control devices that consume little power. As a result, recently designed control systems have employed many semi-active control devices for the control of a structure. In the future, it is envisioned that structural control systems will be large-scale systems defined by high actuation and sensor densities. Decentralized control approaches have been used to control large-scale systems that are too complex for a traditional centralized approach, such as linear quadratic regulation (LQR). This paper describes the derivation of energy market-based control (EMBC), a decentralized approach that models the structural control system as a competitive marketplace. The interaction of free-market buyers and sellers result in an optimal allocation of limited control system resources such as control energy. The Kajima-Shizuoka Building and a 20-story benchmark structure are selected as illustrative examples to be used for comparison of the EMBC and centralized LQR approaches.

Design and performance validation of a wireless sensing unit for structural monitoring applications

Lynch, Jerome Peter,Law, Kincho H.,Kiremidjian, Anne S.,Carryer, Ed,Farrar, Charles R.,Sohn, Hoon,Allen, David W.,Nadler, Brett,Wait, Jeannette R. Techno-Press 2004 Structural Engineering and Mechanics, An Int'l Jou Vol.17 No.3

There exists a clear need to monitor the performance of civil structures over their operational lives. Current commercial monitoring systems suffer from various technological and economic limitations that prevent their widespread adoption. The wires used to route measurements from system sensors to the centralized data server represent one of the greatest limitations since they are physically vulnerable and expensive from an installation and maintenance standpoint. In lieu of cables, the introduction of low-cost wireless communications is proposed. The result is the design of a prototype wireless sensing unit that can serve as the fundamental building block of wireless modular monitoring systems (WiMMS). An additional feature of the wireless sensing unit is the incorporation of computational power in the form of state-of-art microcontrollers. The prototype unit is validated with a series of laboratory and field tests. The Alamosa Canyon Bridge is employed to serve as a full-scale benchmark structure to validate the performance of the wireless sensing unit in the field. A traditional cable-based monitoring system is installed in parallel with the wireless sensing units for performance comparison.

An integrated monitoring system for life-cycle management of wind turbines

Kay Smarsly,Dietrich Hartmann,Kincho H. Law 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.12 No.2

With an annual growth rate of about 30%, wind energy systems, such as wind turbines, represent one of the fastest growing renewable energy technologies. Continuous structural health monitoring of wind turbines can help improving structural reliability and facilitating optimal decisions with respect to maintenance and operation at minimum associated life-cycle costs. This paper presents an integrated monitoring system that is designed to support structural assessment and life-cycle management of wind turbines. The monitoring system systematically integrates a wide variety of hardware and software modules, including sensors and computer systems for automated data acquisition, data analysis and data archival, a multiagent-based system for self-diagnosis of sensor malfunctions, a model updating and damage detection framework for structural assessment, and a management module for monitoring the structural condition and the operational efficiency of the wind turbine. The monitoring system has been installed on a 500 kW wind turbine located in Germany. Since its initial deployment in 2009, the system automatically collects and processes structural, environmental, and operational wind turbine data. The results demonstrate the potential of the proposed approach not only to ensure continuous safety of the structures, but also to enable cost-efficient maintenance and operation of wind turbines.

Embedment of structural monitoring algorithms in a wireless sensing unit

Lynch, Jerome Peter,Sundararajan, Arvind,Law, Kincho H.,Kiremidjian, Anne S.,Kenny, Thomas,Carryer, Ed Techno-Press 2003 Structural Engineering and Mechanics, An Int'l Jou Vol.15 No.3

Complementing recent advances made in the field of structural health monitoring and damage detection, the concept of a wireless sensing network with distributed computational power is proposed. The fundamental building block of the proposed sensing network is a wireless sensing unit capable of acquiring measurement data, interrogating the data and transmitting the data in real time. The computational core of a prototype wireless sensing unit can potentially be utilized for execution of embedded engineering analyses such as damage detection and system identification. To illustrate the computational capabilities of the proposed wireless sensing unit, the fast Fourier transform and auto-regressive time-series modeling are locally executed by the unit. Fast Fourier transforms and auto-regressive models are two important techniques that have been previously used for the identification of damage in structural systems. Their embedment illustrates the computational capabilities of the prototype wireless sensing unit and suggests strong potential for unit installation in automated structural health monitoring systems.

An integrated monitoring system for life-cycle management of wind turbines

Smarsly, Kay,Hartmann, Dietrich,Law, Kincho H. Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.12 No.2

With an annual growth rate of about 30%, wind energy systems, such as wind turbines, represent one of the fastest growing renewable energy technologies. Continuous structural health monitoring of wind turbines can help improving structural reliability and facilitating optimal decisions with respect to maintenance and operation at minimum associated life-cycle costs. This paper presents an integrated monitoring system that is designed to support structural assessment and life-cycle management of wind turbines. The monitoring system systematically integrates a wide variety of hardware and software modules, including sensors and computer systems for automated data acquisition, data analysis and data archival, a multiagent-based system for self-diagnosis of sensor malfunctions, a model updating and damage detection framework for structural assessment, and a management module for monitoring the structural condition and the operational efficiency of the wind turbine. The monitoring system has been installed on a 500 kW wind turbine located in Germany. Since its initial deployment in 2009, the system automatically collects and processes structural, environmental, and operational wind turbine data. The results demonstrate the potential of the proposed approach not only to ensure continuous safety of the structures, but also to enable cost-efficient maintenance and operation of wind turbines.

Combination of a Time Reversal Process and a Consecutiv Outlier Analysis for Baseline-free Damage Diagnosis

Sohn, Hoon,Hyun Woo Park,,Law, Kincho H.,Farrar, Charles R. Sage Science Press (UK) 2007 Journal of intelligent material systems and struct Vol.18 No.4

<P>A structural health monitoring system is developed for continuous online monitoring of delamination initiation and growth in composite structures. Structural health monitoring problems are often cast in the context of a statistical pattern recognition paradigm, in which a damage state of a structure is inferred by comparing test data with baseline data. However, subtle signal changes due to damage can often be masked by larger ambient variation of operational and environmental conditions of an in-service structure. Therefore, it is critical for the development of a robust monitoring system to minimize false-positive indications of damage caused by the undesired operational and environmental variation of the structure. The issue of minimizing damage misclassification has been addressed in this article by developing an instantaneous damage detection scheme that does not rely on past baseline data. The proposed instantaneous damage diagnosis is based on the concepts of time reversal acoustics and consecutive outlier analysis, and the proposed damage diagnosis has been tested for detecting delamination in composite plates.</P>

Decentralized civil structural control using real-time wireless sensing and embedded computing

Wang, Yang,Swartz, R. Andrew,Lynch, Jerome P.,Law, Kincho H.,Lu, Kung-Chun,Loh, Chin-Hsiung Techno-Press 2007 Smart Structures and Systems, An International Jou Vol.3 No.3

Structural control technologies have attracted great interest from the earthquake engineering community over the last few decades as an effective method of reducing undesired structural responses. Traditional structural control systems employ large quantities of cables to connect structural sensors, actuators, and controllers into one integrated system. To reduce the high-costs associated with labor-intensive installations, wireless communication can serve as an alternative real-time communication link between the nodes of a control system. A prototype wireless structural sensing and control system has been physically implemented and its performance verified in large-scale shake table tests. This paper introduces the design of this prototype system and investigates the feasibility of employing decentralized and partially decentralized control strategies to mitigate the challenge of communication latencies associated with wireless sensor networks. Closed-loop feedback control algorithms are embedded within the wireless sensor prototypes allowing them to serve as controllers in the control system. To validate the embedment of control algorithms, a 3-story half-scale steel structure is employed with magnetorheological (MR) dampers installed on each floor. Both numerical simulation and experimental results show that decentralized control solutions can be very effective in attaining the optimal performance of the wireless control system.

Power evaluation of flutter-based electromagnetic energy harvesters using computational fluid dynamics simulations

Park, Jinkyoo,Morgenthal, Guido,Kim, Kyoungmin,Kwon, Soon-Duck,Law, Kincho H Sage Science Press (UK) 2014 Journal of intelligent material systems and struct Vol. No.

<P>H- and T-shaped cross sections are known to be susceptible to rotational single-degree-of-freedom aerodynamic instabilities. Here, such self-excited aerodynamic response of a T-shaped cantilever structure is used to extract energy, which is then converted into electric power through an electromagnetic transducer. The complex fluid–structure interaction between the cantilever harvester and wind flow is analyzed numerically and experimentally. To study the dynamic response of the cantilever and estimate the power output from the harvester, numerical simulations based on the vortex particle method are performed to determine the aerodynamic damping of the harvester section and to analyze the stability behavior of the section. The estimated aerodynamic damping parameter together with the mechanical and electrical damping parameters in the harvester are used to find the critical wind speed of flutter onset as well as the optimum load resistance. Wind tunnel experiments are conducted to validate the simulation results.</P>

An information modeling framework for bridge monitoring

Jeong, Seongwoon,Hou, Rui,Lynch, Jerome P.,Sohn, Hoon,Law, Kincho H. Elsevier 2017 Advances in engineering software Vol.114 No.-

<P><B>Abstract</B></P> <P>Bridge management involves a variety of information from different data sources, including geometric model, analysis model, bridge management system (BMS) and structural health monitoring (SHM) system. Current practice of bridge management typically handles these diverse types of data using isolated systems and operates with limited use of the data. Sharing and integration of such information would facilitate meaningful use of the information and improve bridge management, as well as enhance bridge operation and maintenance and public safety. In many industries, information models and interoperability standards have been developed and employed to facilitate information sharing and collaboration. Given the success of building information modeling (BIM) in the Architecture, Engineering and Construction (AEC) industry, efforts have been initiated to develop frameworks and standards for bridge information modeling (BrIM). Current developments of BrIM focus primarily on the physical descriptions of bridge structures, such as geometry and material properties. This paper presents an information modeling framework for supporting bridge monitoring applications. The framework augments and extends the prior work on the OpenBrIM standards to further capture the information relevant to engineering analysis and sensor network. Implementation of the framework employs an open-source NoSQL database system for scalability, flexibility and performance. The framework is demonstrated using bridge information and sensor data collected from the Telegraph Road Bridge located in Monroe, Michigan. The results show that the bridge information modeling framework can potentially facilitate the integration of information involved in bridge monitoring applications, and effectively support and provide services to retrieve and utilize the information.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An information modeling framework for supporting bridge monitoring applications is proposed. </LI> <LI> The framework extends the prior work on the OpenBrIM standards to capture the information relevant to engineering analysis and sensor network. </LI> <LI> Implementation of the framework employs a NoSQL database system for scalability, flexibility and performance. </LI> <LI> The framework is demonstrated using bridge information and sensor data collected from the Telegraph Road Bridge located in Monroe, Michigan. </LI> </UL> </P>

A NoSQL data management infrastructure for bridge monitoring

Seongwoon Jeong,Yilan Zhang,Jaemook Choi,Jerome P. Lynch,Hoon Sohn,Kincho H. Law 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.17 No.4

Advances in sensor technologies have led to the instrumentation of sensor networks for bridge monitoring and management. For a dense sensor network, enormous amount of sensor data are collected. The data need to be managed, processed, and interpreted. Data management issues are of prime importance for a bridge management system. This paper describes a data management infrastructure for bridge monitoring applications. Specifically, NoSQL database systems such as MongoDB and Apache Cassandra are employed to handle time-series data as well the unstructured bridge information model data. Standard XML-based modeling languages such as OpenBrIM and SensorML are adopted to manage semantically meaningful data and to support interoperability. Data interoperability and integration among different components of a bridge monitoring system that includes on-site computers, a central server, local computing platforms, and mobile devices are illustrated. The data management framework is demonstrated using the data collected from the wireless sensor network installed on the Telegraph Road Bridge, Monroe, MI.