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  • Apr
    28

    SPREE Seminar: Hoang Nguyen

    McCormick - Civil and Environmental Engineering

    11:00 AM

    EVENT DETAILS

    Effect of Crack-Parallel Compression or Tension on Structural Scaling strength of Materials – as applied to Concrete, Composite and Metal

    ABSTRACT
    In all widely used fracture test specimens, the compressive or tensile stress parallel to the plane of growing crack is negligible, and thus its effect cannot be revealed. The classical fracture models, including the cohesive crack model, cannot capture any effect of such crack-parallel normal stress and strain, except parametrically, because they do not figure as the basic thermodynamic variables. To capture these effect, the fracture process zone must be modeled tensorially, by a strain-softening damage constitutive law. Here it is shown experimentally, and documented by crack band finite element simulations with microplane model M7, that the crack-parallel normal stresses have a major effect in quasibrittle materials such as concrete. They are shown to cause a major decrease or increase of the Mode I (opening) fracture energy Gf (or fracture toughness KIc. The experiments introduce a modification of the standard three-point bend test, whose idea is the use plastic pads with a near-perfect yield plateau to first generate compression, and a gap at end supports to close later and generate bending. The experiments show and the microplane model confirms that a small crack-parallel compression greatly increases Gf (even doubling it or more), but a higher compression reduces Gf greatly, which represents the case of compression splitting. The microplane model predictions fit the test results closely. Thus validated, it shows that crack-parallel tension reduces Gf, and further that a compressive or tensile stress normal to the specimen plate has a similar major effect on Gf. High crack-parallel stresses arise, e.g., in shear failure of reinforced concrete beams or slabs, and they are typical for prestressed concrete, as well as in hydraulic fracturing of shale.

    BIOGRAPHY
    Hoang received his Bachelor's degree in Civil Engineering from Bach Khoa University (old name Ho Chi Minh city University of Technology, Vietnam) in 2014. He then earned his Master's degree in Theoretical and Applied Mechanics (TAM) from Northwestern University (USA) in 2017. Since then, he has been jointly advised by Professor Horacio Espinosa and Prof. Zdeněk Bažant to pursue a Ph. D. degree also in TAM. Hoang is interested in multiphysics and multiscale phenomena in rock-like materials (primarily concrete), and how to apply his understanding of those phenomena into sustaining structural serviceability and improving other human-structure interaction activities. Aside from research, he enjoys reading natural and health science books and jamming mash-up from random songs.

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    TIME Wednesday, April 28, 2021 at 11:00 AM - 12:00 PM

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    CONTACT Tierney Acott    tierney.acott@northwestern.edu EMAIL

    CALENDAR McCormick - Civil and Environmental Engineering

  • May
    13

    TAM Seminar: Dr. Nathalie Vriend

    McCormick - Civil and Environmental Engineering

    10:00 AM

    EVENT DETAILSmore info

    TIME Thursday, May 13, 2021 at 10:00 AM - 11:00 AM

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    CONTACT Alison Rodriguez    alison.rodriguez@northwestern.edu EMAIL

    CALENDAR McCormick - Civil and Environmental Engineering

  • May
    14

    Social Equity & Racial Justice Seminar: Lee Bey

    McCormick - Civil and Environmental Engineering

    2:00 PM

    EVENT DETAILS

    TIME Friday, May 14, 2021 at 2:00 PM - 3:00 PM

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    CONTACT Tierney Acott    tierney.acott@northwestern.edu EMAIL

    CALENDAR McCormick - Civil and Environmental Engineering

  • May
    19

    Osterberg Lecture: Edward Kavazanjian, Jr.

    McCormick - Civil and Environmental Engineering

    11:00 AM

    EVENT DETAILS

    TIME Wednesday, May 19, 2021 at 11:00 AM - 12:30 PM

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    CONTACT Alison Rodriguez    alison.rodriguez@northwestern.edu EMAIL

    CALENDAR McCormick - Civil and Environmental Engineering

  • May
    20

    Julio M. Ottino: Prediction, Understanding, and the Unreasonable Effectiveness of Mathematics: A View Through the Window of Mixing

    McCormick-Engineering Sciences and Applied Mathematics

    12:00 PM

    EVENT DETAILS

    TIME Thursday, May 20, 2021 at 12:00 PM - 1:00 PM

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    CONTACT Madeline Kennedy    madeline.kennedy@northwestern.edu EMAIL

    CALENDAR McCormick-Engineering Sciences and Applied Mathematics

  • May
    21

    EES Seminar: Edward Kolodziej

    McCormick - Civil and Environmental Engineering

    2:00 PM

    EVENT DETAILS

    TIME Friday, May 21, 2021 at 2:00 PM - 3:00 PM

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    CONTACT Tierney Acott    tierney.acott@northwestern.edu EMAIL

    CALENDAR McCormick - Civil and Environmental Engineering

  • May
    28

    EES Seminar: Nadine Borduas-Dedekind

    McCormick - Civil and Environmental Engineering

    2:00 PM

    EVENT DETAILS

    TIME Friday, May 28, 2021 at 2:00 PM - 3:00 PM

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    CONTACT Tierney Acott    tierney.acott@northwestern.edu EMAIL

    CALENDAR McCormick - Civil and Environmental Engineering

  • May
    31

    Memorial Day (no classes)

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, May 31, 2021

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Jun
    5

    Spring classes end

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Saturday, June 5, 2021

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Jun
    7

    Spring examinations begin

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, June 7, 2021

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Jun
    12

    Spring examinations end

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Saturday, June 12, 2021

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Jun
    13

    McCormick School of Engineering Convocation (Tentative)

    McCormick School of Engineering and Applied Science

    1:00 PM Ryan Field

    EVENT DETAILSmore info

    TIME Sunday, June 13, 2021 at 1:00 PM - 3:00 PM

    LOCATION Ryan Field    map it

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    CONTACT Northwestern Engineering Events    northwestern-engineering-events@northwestern.edu EMAIL

    CALENDAR McCormick School of Engineering and Applied Science

  • Jun
    14

    Commencement (Tentative)

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Monday, June 14, 2021

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar

  • Jun
    18

    Spring Degrees Conferred

    University Academic Calendar

    All Day

    EVENT DETAILS

    TIME Friday, June 18, 2021

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    CONTACT Office of the Registrar    nu-registrar@northwestern.edu EMAIL

    CALENDAR University Academic Calendar