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Gregory M Hulbert - One of the best experts on this subject based on the ideXlab platform.

  • baseband Methods of component mode synthesis for non proportionally damped systems
    Mechanical Systems and Signal Processing, 2003
    Co-Authors: Jeffrey A Morgan, Christophe Pierre, Gregory M Hulbert
    Abstract:

    Abstract This paper presents several new baseband Methods of component mode synthesis (CMS) for non-proportionally damped systems. In contrast to most existing CMS approaches, these Methods are based upon a first-order state-space formulation which engenders complex-valued modal vectors, transformation matrices, and reduced structural matrices. Two new Methods are presented. These are baseband versions of ‘constraint modes’ and ‘residual Flexibility’ Methods. The constraint modes Method is applicable when existing finite element matrices can be employed for analytical implementation. The residual Flexibility Method is used within an experimentally based implementation with test data. The experimentally based Methodology produces matrices that are compatible with the analytical matrices thus, system models comprising both types of matrices can be analysed as a single assembly. Theoretical developments are presented in this paper and conclusions are drawn.

  • nonbaseband residual Flexibility Method of component mode synthesis for proportionally damped systems
    AIAA Journal, 1999
    Co-Authors: Jeffrey A Morgan, Christophe Pierre, Gregory M Hulbert
    Abstract:

    Several new component mode synthesis Methods are presented for the dynamic analysis of proportionally damped systems in nonbaseband frequency regions of interest. The first Method is based on the Craig-Bampton constraint modes approach (Craig, R. R., Jr., and Bampton, M. C. C., Coupling of Substructures for Dynamic Analyses,' AIAA Journal, Vol. 6, No. 7, 1968, pp. 1313-1319) but uses a modified dynamic transformation Method that produces constraint modes at two frequencies, normally the upper and lower frequency limits of the region of interest. Then, a second Method is presented that is similar to the first but uses a residual Flexibility formulation. This second Method is ideally suited for use with test-derived data and becomes the basis for a new nonbaseband experimentally based Method. The procedure for implementing the experimentally based Method is then presented. Finally, an analytical simulation is conducted using error-free data to demonstrate the new Methods on a system of two coupled beams.

Jeffrey A Morgan - One of the best experts on this subject based on the ideXlab platform.

  • baseband Methods of component mode synthesis for non proportionally damped systems
    Mechanical Systems and Signal Processing, 2003
    Co-Authors: Jeffrey A Morgan, Christophe Pierre, Gregory M Hulbert
    Abstract:

    Abstract This paper presents several new baseband Methods of component mode synthesis (CMS) for non-proportionally damped systems. In contrast to most existing CMS approaches, these Methods are based upon a first-order state-space formulation which engenders complex-valued modal vectors, transformation matrices, and reduced structural matrices. Two new Methods are presented. These are baseband versions of ‘constraint modes’ and ‘residual Flexibility’ Methods. The constraint modes Method is applicable when existing finite element matrices can be employed for analytical implementation. The residual Flexibility Method is used within an experimentally based implementation with test data. The experimentally based Methodology produces matrices that are compatible with the analytical matrices thus, system models comprising both types of matrices can be analysed as a single assembly. Theoretical developments are presented in this paper and conclusions are drawn.

  • nonbaseband residual Flexibility Method of component mode synthesis for proportionally damped systems
    AIAA Journal, 1999
    Co-Authors: Jeffrey A Morgan, Christophe Pierre, Gregory M Hulbert
    Abstract:

    Several new component mode synthesis Methods are presented for the dynamic analysis of proportionally damped systems in nonbaseband frequency regions of interest. The first Method is based on the Craig-Bampton constraint modes approach (Craig, R. R., Jr., and Bampton, M. C. C., Coupling of Substructures for Dynamic Analyses,' AIAA Journal, Vol. 6, No. 7, 1968, pp. 1313-1319) but uses a modified dynamic transformation Method that produces constraint modes at two frequencies, normally the upper and lower frequency limits of the region of interest. Then, a second Method is presented that is similar to the first but uses a residual Flexibility formulation. This second Method is ideally suited for use with test-derived data and becomes the basis for a new nonbaseband experimentally based Method. The procedure for implementing the experimentally based Method is then presented. Finally, an analytical simulation is conducted using error-free data to demonstrate the new Methods on a system of two coupled beams.

Giles, Ryan K. - One of the best experts on this subject based on the ideXlab platform.

  • Development of a Long-term, Multimetric Structural Health Monitoring System for a Historic Steel Truss Swing Bridge
    Newmark Structural Engineering Laboratory. University of Illinois at Urbana-Champaign., 2015
    Co-Authors: Giles, Ryan K., Spencer, Billie F.
    Abstract:

    The bridge stock across the United States is ageing, with many bridges approaching the end of their design life. The situation is so dire that the American Society of Civil Engineers gave the nation’s bridges a grade of “C+” in the 2013 edition of their Report Card on America’s Infrastructure. In fact, at the end of 2011, nearly a quarter of all bridges in the United States were classified as either structurally deficient or functionally obsolete. Thus, the nation’s bridges are in desperate need of rehabilitation and maintenance. However, limited funds are available for the repair of bridges. Management of the nation’s bridge infrastructure requires an efficient and effective use of available funds to direct the maintenance and repair efforts. Structural health monitoring has the potential to supplement the current routine of scheduled bridge inspections by providing an objective and detailed source of information about the status of the bridge. This research develops a framework for the long-term monitoring of bridges that leverages multimetric data to provide value to the bridge manager. The framework is applied to the Rock Island Arsenal Government Bridge. This bridge is a historic, steel truss, swing bridge that spans the Mississippi River between Rock Island, IL and Davenport, IA. The bridge is owned and operated by the US Army Corps of Engineers (USACE) and is a vital link for vehicular, train, and barge traffic. The USACE had a system of fiber optic strain gages installed on the bridge. As part of this research, this system was supplemented with a wireless sensor network that measured accelerations on the bridge. The multimetric data from the sensor systems was collected using a program developed in the course of this research. The data was then analyzed and metrics were developed that could be used to determine the health of the structure and the sensor networks themselves. Statistical process control Methods were established to detect anomalous behavior in the short and long term time scales. Methods to locate and quantify the damage that has occurred in the structure once an anomaly has been detected were demonstrated. One of the Methods developed as part of this research was a first order Flexibility Method. The SHM system this research develops has the desirable characteristics of being continuous temporally, multimetric, scalable, robust, autonomous, and informative. By necessity, some aspects of the developed SHM framework are unique and customized exclusively for the Rock Island Government Bridge. However, the principles developed in the framework are applicable to the development of an SHM system for any other bridge. Application of the SHM framework this research develops to other bridges has the potential to increase objectivity in the evaluation of bridges and focus maintenance efforts and funds on the bridges that are most critical to the public safety.Financial support for this research was provided in part by the Army Corps of Engineers Construction Engineering Research Laboratory (CERL) through a subcontract with Mandaree Enterprise Corporation.Ope

  • Development of a long-term, multimetric structural health monitoring system for a historic steel truss swing bridge
    2013
    Co-Authors: Giles, Ryan K.
    Abstract:

    The bridge stock across the United States is ageing, with many bridges approaching the end of their design life. The situation is so dire that the American Society of Civil Engineers gave the nation’s bridges a grade of “C+” in the 2013 edition of their “Report Card on America’s Infrastructure.” In fact, at the end of 2011, nearly a quarter of all bridges in the United States were classified as either structurally deficient or functionally obsolete. Thus, the nation’s bridges are in desperate need of rehabilitation and maintenance. However, limited funds are available for the repair of bridges. Management of the nation’s bridge infrastructure requires an efficient and effective use of available funds to direct the maintenance and repair efforts. Structural health monitoring has the potential to supplement the current routine of scheduled bridge inspections by providing an objective and detailed source of information about the status of the bridge. This research develops a framework for the long-term monitoring of bridges that leverages multimetric data to provide value to the bridge manager. The framework is applied to the Rock Island Arsenal Government Bridge. This bridge is a historic, steel truss, swing bridge that spans the Mississippi River between Rock Island, IL and Davenport, IA. The bridge is owned and operated by the US Army Corps of Engineers (USACE) and is a vital link for vehicular, train, and barge traffic. The USACE had a system of fiber optic strain gages installed on the bridge. As part of this research, this system was supplemented with a wireless sensor network that measured accelerations on the bridge. The multimetric data from the sensor systems was collected using a program developed in the course of this research. The data was then analyzed and metrics were developed that could be used to determine the health of the structure and the sensor networks themselves. Statistical process control Methods were established to detect anomalous behavior in the short and long term time scales. Methods to locate and quantify the damage that has occurred in the structure once an anomaly has been detected were demonstrated. One of the Methods developed as part of this research was a first order Flexibility Method. The SHM system this research develops has the desirable characteristics of being continuous temporally, multimetric, scalable, robust, autonomous, and informative. By necessity, some aspects of the developed SHM framework are unique and customized exclusively for the Rock Island Government Bridge. However, the principles developed in the framework are applicable to the development of an SHM system for any other bridge. Application of the SHM framework this research develops to other bridges has the potential to increase objectivity in the evaluation of bridges and focus maintenance efforts and funds on the bridges that are most critical to the public safety

Christophe Pierre - One of the best experts on this subject based on the ideXlab platform.

  • baseband Methods of component mode synthesis for non proportionally damped systems
    Mechanical Systems and Signal Processing, 2003
    Co-Authors: Jeffrey A Morgan, Christophe Pierre, Gregory M Hulbert
    Abstract:

    Abstract This paper presents several new baseband Methods of component mode synthesis (CMS) for non-proportionally damped systems. In contrast to most existing CMS approaches, these Methods are based upon a first-order state-space formulation which engenders complex-valued modal vectors, transformation matrices, and reduced structural matrices. Two new Methods are presented. These are baseband versions of ‘constraint modes’ and ‘residual Flexibility’ Methods. The constraint modes Method is applicable when existing finite element matrices can be employed for analytical implementation. The residual Flexibility Method is used within an experimentally based implementation with test data. The experimentally based Methodology produces matrices that are compatible with the analytical matrices thus, system models comprising both types of matrices can be analysed as a single assembly. Theoretical developments are presented in this paper and conclusions are drawn.

  • nonbaseband residual Flexibility Method of component mode synthesis for proportionally damped systems
    AIAA Journal, 1999
    Co-Authors: Jeffrey A Morgan, Christophe Pierre, Gregory M Hulbert
    Abstract:

    Several new component mode synthesis Methods are presented for the dynamic analysis of proportionally damped systems in nonbaseband frequency regions of interest. The first Method is based on the Craig-Bampton constraint modes approach (Craig, R. R., Jr., and Bampton, M. C. C., Coupling of Substructures for Dynamic Analyses,' AIAA Journal, Vol. 6, No. 7, 1968, pp. 1313-1319) but uses a modified dynamic transformation Method that produces constraint modes at two frequencies, normally the upper and lower frequency limits of the region of interest. Then, a second Method is presented that is similar to the first but uses a residual Flexibility formulation. This second Method is ideally suited for use with test-derived data and becomes the basis for a new nonbaseband experimentally based Method. The procedure for implementing the experimentally based Method is then presented. Finally, an analytical simulation is conducted using error-free data to demonstrate the new Methods on a system of two coupled beams.

Joosen Wouter - One of the best experts on this subject based on the ideXlab platform.

  • Object to NoSQL Database Mappers (ONDM): A systematic survey and comparison of frameworks
    'Elsevier BV', 2019
    Co-Authors: Reniers Vincent, Van Landuyt Dimitri, Rafique Ansar, Joosen Wouter
    Abstract:

    © 2019 Elsevier Ltd Context: Software applications frequently interact with database systems to persist and retrieve objects. Object mapping frameworks address (i) the bi-directional conversion of data between object and target database and (ii) provide a programmatic interface for querying and storing data. The rise of NoSQL databases poses challenges beyond object-relational mapping (ORM) frameworks to abstract from various data models and non-standardized API's, but also take into account the different database capabilities (e.g. unsupported query operators, data ordering). Objective: A systematic survey study of existing Object-NoSQL data mapping (ONDM) frameworks. Specific focus is given to the level of abstraction of data and operations to multiple database technologies, as a means to limit vendor and technology lock-in and an enabler for multi-store and polyglot architectures. Additional attention is paid to mapping strategies that are specific to NoSQL databases (e.g. object embedding, schema Flexibility). Method: A systematic search Methodology identifies all relevant object mapping frameworks (in total 341 frameworks). Subsequently, a subset of ONDM frameworks is selected and systematically compared in terms of criteria of: database support, interface and query functionality, architecture and software coupling. Secondly, we provide an in-depth comparison of object-oriented mapping strategies for classes, inheritance, relationships, and attribute types to NoSQL data models. Results: ONDM frameworks are most prevalent in Java, Node.JS, Python, and overall 54 frameworks support multiple (NoSQL) databases. Interfaces are frequently standardized and commonly feature a uniform query language and even native DB query mapping. However, database portability may be hindered due to non-uniform abstractions. As for mapping strategies, current frameworks do not fully exploit NoSQL's modeling potential, such as (i) the embedding of relationship data within referring objects’ records, (ii) mapping at the individual object-level vs. class-level, and (iii) lacking collection normalization despite being supported for associations or when using relational databases. Conclusion: The study consolidates knowledge on available ONDM frameworks, and applied object-document, object-graph, and object-column mapping patterns. The study can guide practitioners in framework selection, and pinpoints areas of future development and research in this domain, most notably towards improved support for flexible, NoSQL-aware mapping strategies.status: publishe

  • Object to NoSQL Database Mappers (ONDM): A systematic survey and comparison of frameworks
    'Elsevier BV', 2019
    Co-Authors: Reniers Vincent, Van Landuyt Dimitri, Rafique Ansar, Joosen Wouter
    Abstract:

    Context: Software applications frequently interact with database systems to persist and retrieve objects. Object mapping frameworks address (i) the bi-directional conversion of data between object and target database and (ii) provide a programmatic interface for querying and storing data. The rise of NoSQL databases poses challenges beyond object-relational mapping (ORM) frameworks to abstract from various data models and non-standardized API’s, but also take into account the different database capabilities (e.g. unsupported query operators, data ordering). Objective: A systematic survey study of existing Object-NoSQL data mapping (ONDM) frameworks. Specific focus is given to the level of abstraction of data and operations to multiple database technologies, as a means to limit vendor and technology lock-in and an enabler for multi-store and polyglot architectures. Additional attention is paid to mapping strategies that are specific to NoSQL databases (e.g. object embedding, schema Flexibility). Method: A systematic search Methodology identifies all relevant object mapping frameworks (in total 341 frameworks). Subsequently, a subset of ONDM frameworks is selected and systematically compared in terms of criteria of: database support, interface and query functionality, architecture and software coupling. Secondly, we provide an in-depth comparison of object-oriented mapping strategies for classes, inheritance, relationships, and attribute types to NoSQL data models. Results: ONDM frameworks are most prevalent in Java, Node.JS, Python, and overall 54 frameworks support multiple (NoSQL) databases. Interfaces are frequently standardized and commonly feature a uniform query language and even native DB query mapping. However, database portability may be hindered due to non-uniform abstractions. As for mapping strategies, current frameworks do not fully exploit NoSQL’s modeling potential, such as (i) the embedding of relationship data within referring objects’ records, (ii) mapping at the individual object-level vs. class-level, and (iii) lacking collection normalization despite being supported for associations or when using relational databases. Conclusion: The study consolidates knowledge on available ONDM frameworks, and applied object-document, object-graph, and object-column mapping patterns. The study can guide practitioners in framework selection, and pinpoints areas of future development and research in this domain, most notably towards improved support for flexible, NoSQL-aware mapping strategies.status: publishe