Filters

Reset filters

Settings

Has files: true

Search Results

Now showing 1 - 10 of 75
  • No Thumbnail Available
    Item
    It's Happening at State: July 18, 2001
    (North Dakota State University, 2001-07-18)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.
  • No Thumbnail Available
    Item
    It's Happening at State: January 07, 2004
    (North Dakota State University, 2004-01-07)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.
  • No Thumbnail Available
    Item
    It's Happening at State: September 05, 2007
    (North Dakota State University, 2007-09-05)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.
  • No Thumbnail Available
    Item
    NDSU Magazine : Spring 2003
    (North Dakota State University, 2003)
  • No Thumbnail Available
    Item
    Computational Biomechanics of Blast-Induced Traumatic Brain Injury: Role of Loading Directionality, Head Protection, and Blast Flow Mechanics
    (North Dakota State University, 2015) Sarvghad-Moghaddam, Hesam
    In this dissertation, blast-induced traumatic brain injury (bTBI) is studied with respect to the blast wave directionality, mitigation capability of helmet/faceshield, and blast flow mechanics using finite element (FE) and computational fluid dynamics (CFD) schemes. For the FE study, simulations are performed on a detailed FE head model using LS-DYNA, and CFD simulations are carried out using the ANSYS-CFX to examine the underwash development by analyzing the behavior of blast flow from different directions. The following tasks are conducted. First, the effects of the loading direction on the mechanical response of the head and brain is investigated through impact and blast induced loading on the head. Due to the differences in the shape, function, and tolerance of brain components, the response of the head/brain varies with the direction of the impact and blast waves. In identical situations, the head shows to have lower tolerance to side loading. Second, the inclusion of the faceshield as a potential head protective tool against blast threats is evaluated with respect to blast direction. The helmet-faceshield and helmeted assemblies are shown to be most efficient when the head is exposed to blast from the front and top sides, respectively. Faceshield is observed to be effective only in front blast as it might impose either adverse or no effects in other directions. The shockwaves are seen to form a high pressure region in head-helmet-faceshield gap (underwash effect) which induces elevated pressures on the skull. Third, the underwash effect’s mechanism is investigated through CFD simulations of supersonic shockwave flow around the helmeted head assemblies. CFD results reveals that the backpressure is produced due to the creation of a backflow in the exterior flow on the outgoing interior flow. The bottom and side shockwave directions predict the highest underwash overpressures, respectively. Finally, the ICP and shear stress of the brain is evaluated in case of underwash incidence. FEA results show that underwash overpressure greatly changes with the blast direction. It is concluded that underwash clearly altered the tissue response of the brain as it increases ICP levels at the countercoup site and imparts elevated skull flexure.
  • No Thumbnail Available
    Item
    Influence of Molecular Interactions on Elastic Properties and Oxygen Diffusion in PolyButylene Terephthalate Polymer: A Molecular Dynamics Study
    (North Dakota State University, 2012) Raviprasad, Muniyamuthu
    In most barrier applications, both mechanical and diffusion properties of the material are important. In this thesis the evaluation of molecular mechanisms responsible for the enhanced elastic properties of Polymer Clay Nanocomposites (PCNs) and the molecular mechanisms of Oxygen diffusion in PolyButylene Terephthalate polymer are presented. Interaction energy between PCN constituents, conformational changes of polymer, interaction energy between Oxygen molecule and polymer, rate of Oxygen and Oxygen diffusion coefficient are evaluated. Molecular simulation studies of PolyButylene Terephthalate (PBT) clay nanocomposite and Nylon6 clay nanocomposite show that a higher crystallinity polymer such as PBT would require higher attractive and repulsive interactions with organic modifier in order to make significant change in the crystallinity of PBT in the nanocomposite and in turn enhance the elastic modulus and hardness. Molecular interactions energy between Oxygen molecule and polymer, change in polymer conformation caused by thermal energy assist the Oxygen molecule to diffuse through polymer.
  • No Thumbnail Available
    Item
    It's Happening at State: June 13, 2007
    (North Dakota State University, 2007-06-13)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.
  • No Thumbnail Available
    Item
    It's Happening at State: January 12, 2000
    (North Dakota State University, 2000-01-12)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.
  • No Thumbnail Available
    Item
    It's Happening at State: September 13, 2006
    (North Dakota State University, 2006-09-13)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.
  • No Thumbnail Available
    Item
    It's Happening at State: September 29, 2004
    (North Dakota State University, 2004-09-29)
    Provides summary information of news and events of interest to the faculty and staff of NDSU.