University of Vermont

Civil & Environmental Engineering

Infrastructure Systems

  • (BRIGE) Multiscale Model-Data Fusion for Structural Health Monitoring of Fracture Critical Structures
    PI: Eric M. Hernandez
    Co-PI: None
    Graduate Students Involved: Kalil Erazo and Nestor Polanco

  • (CAREER) Structural Health Monitoring, Diagnosis and Prognosis of Minimally Instrumented Structural Systems
    PI: Eric M. Hernandez
    Co-PI: None
    Graduate Students Involved: Nestor Polanco

  • Investigation of Coupled Processes Within Fractures in Enhanced Geothermal Systems
    PI: Ehsan Ghazanfari
    Co-PI: None
    Graduate Students Involved: Robert Caulk, Arash Kamali-Asl

  • Thermal Response Investigation of Geothermal Energy Pile
    PI: Ehsan Ghazanfari
    Co-PI: None
    Graduate Students Involved: Robert Caulk

  • BRIGE: Multiscale Model-Data Fusion for Structural Health Monitoring of Fracture Critical Structures

    PI: Eric M. Hernandez

    Co-PI: None

    Graduate Students Involved: Kalil Erazo and Nestor Polanco

    Description: This project aims to develop a framework for structural health monitoring, diagnosis and prognosis of fracture critical structures. Fracture critical structures are those in which the failure of a single component can generate the failure of the complete system or a large portion of it. Recent catastrophic failures of these types of structures, especially bridges, have highlighted the need for a new and transformative approach to the problem. This project will develop the computational and data analysis tools necessary to continuously monitor fracture critical structures and help prevent such failures. The multiscale model-data fusion framework relies on a series of models, which represent the mechanical behavior of the structure at various scales of interest, and vibration measurements of local and global structural response. The project will develop algorithms capable of optimally combining the predictive capabilities of multiscale finite element models and sensor measurements, to reconstruct in real-time the complete response of the structure. The reconstructed response allows assessment of the current state of cumulative fatigue damage throughout the structure, thus anticipating potential damage before it reaches a critical level. The estimated damage condition, with its associated uncertainty is projected into the future and an estimate of the structural reliability can be obtained. The research involves development of computational algorithms, laboratory experiments and field validation using real data from an instrumented operational bridge in Vermont. The methods developed in this project will aide engineers to perform smarter early diagnosis and predictive maintenance of a multitude of conventional and non-conventional structural systems spanning civil, mechanical, biomedical and electrical applications.

    Publications:

    Erazo, K. and Hernandez, E.M. (2014) “Tracking Stress Response in Structures Using Acceleration Measurements: Experimental Validation”. Mechanical Systems and Signal Processing, 43(1–2): 41-152

    Hernandez, E.M. and Polanco, N.R. (2014) “Reliability-based fatigue monitoring of structures” Proceedings of the European Workshop in Structural Health Monitoring” Nantes, France

    Erazo, K. and Hernandez, E.M. (2014) “Real-time efficient state estimation in nonlinear structural systems” Proceedings of the IX International Conference on Structural Dynamics (EURODYN 2014), Porto, Portugal.

    Hernandez, E.M. (2013) “Real-time monitoring of fatigue reliability of partially instrumented structures excited by random fields” Proceedings of the 11th International Conference on Structural Safety and Reliability (ICOSSAR2013), New York, NY.

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    CAREER: Structural Health Monitoring, Diagnosis and Prognosis of Minimally Instrumented Structural Systems

    PI: Eric M. Hernandez

    Co-PI: None

    Graduate Students Involved: Nestor Polanco, Milad Roohi

    Description: This Faculty Early Career Development (CAREER) Program award will pioneer a novel framework to assess the safety of minimally instrumented structural systems of buildings and bridges. The ultimate goal of the research is to predict remaining life of instrumented structures with knowledge of the state of damage, of material degradation and incorporating uncertainties in the loading environment. The work will focus on two types of loading that abound in civil engineering and that share many common characteristics with other systems in mechanical/bio-medical and aerospace applications. The project will investigate: (i) seismic load induced low-cycle fatigue damage in building structures and (ii) traffic load induced high-cycle fatigue in bridges. The structural systems of buildings and bridges are large, complex and can only be instrumented with a relatively small number of sensors in relation to the total number of degrees-of-freedom. Monitoring the operational safety of these systems is a significant engineering challenge. The computational methods developed in this project will enable early damage diagnosis and future life prognosis of structural systems using minimal instrumentation. This project will integrate multi-disciplinary research, education, and broadens the participation of underrepresented groups in engineering and mathematics.The research in this project investigates a new framework for structural health monitoring of structures subjected to cumulative damage such as fatigue. This project deviates from the conventional approach of identifying damage as changes in model parameters. Instead, this project will investigate a novel framework that combines probabilistic damage mechanics and dynamic state estimation.

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    Investigation of Coupled Processes Within Fractures in Enhanced Geothermal Systems

    PI: Ehsan Ghazanfari

    Co-PI: None

    Graduate Students Involved: Robert Caulk, Arash Kamali-Asl

    Description: The success and sustainability of an EGS d-epends strongly on the permeability of its fracture network. As the geothermal fluid circulates between the injection and production wells through existing or man-made fractures, it interacts with the reservoir rock, and triggers coupled Thermal-Hydro-Mechanical-Chemical (THMC) processes that impact reservoir dynamics and productivity. Change in fracture aperture and permeability due to coupled processes caused by fluid injection/extraction operations could significantly affect the EGS production success. We are conducting laboratory experiments on fractured granite specimens at reservoir conditions to investigate how the coupled processes affect the fracture aperture and permeability evolution at EGS reservoir, and improving the predictive capability of existing models using well-constrained experimental laboratory data.

    Publications:

    Caulk, R., Ghazanfari, E., McCartnery, J. (2016) "Parameterization of a Calibrated Geothermal Energy Pile Model". Journal of Geomechanics for Energy and the Environment, 5 (2016) 1-15



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    Thermal Response Investigation of Geothermal Energy Pile

    PI: Ehsan Ghazanfari

    Co-PI: None

    Graduate Students Involved: Robert Caulk

    Description: The performance of energy piles remains a key area of research. The initial geothermal energy pile design controls the heat transfer and thermal stresses associated with the thermal soil-structure interaction for the lifespan of the foundation. We are using numerical modeling (COMSOL) calibrated with field data to gain more insight into long-term thermal storage and stress mobilization within active energy piles.

    Publications:

    Caulk, R., Ghazanfari, E., Perdrial, J., Perdrial, N. (2016). "Experimental Investigation of Fracture Aperture and Permeability Change within Enhanced Geothermal Systems". Journal of Geothermics, Vol. 62, PP 12-21 (2016)
    Caulk, R., McCartney, J., Ghazanfari, E. (2014), "Calibration of a Geothermal Energy Pile Model", COMSOL Conference, Boston, MA, 2014

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    Last modified August 26 2016 02:19 PM