A. James Clark School of Engineering
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item https://aero.umd.edu/graduate/graduate-student-forms(2018) Kumar, Rubbel; Oran, Elaine S; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The increased use of explosives in military conflicts has been linked to an increase in the number of traumatic brain injuries (TBIs). Assessing the effectiveness of personal protective equipment to mitigate TBIs requires both the ability to replicate the pressure signatures caused by blast waves and an understanding of the interaction between blast waves and human bodies. Computational Fluid Dynamics (CFD) was used to understand the effect of varying different shock tube design parameters and to propose guidelines for selecting shock tube designs to accurately replicate blast wave pressure signatures representative of free-field explosive events. Additionally, a CFD model was developed to represent a shock tube built to mimic the primary overpressure magnitude and impulse loading on the human head surface as a result of free-field explosive events. This model was used to aid in the understanding of flow within the shock tube, characterize the applied pressure loading to a bare head form, augment experimental findings to fully understand the influence of headborne systems on pressure applied to the human head, and support the design of optimized laboratory test methodologies to represent a broad range of free-field blast events.Item Mitigation of Frame Acceleration Induced by a Buried Charge(2010) Brodrick, Thomas James; Foruney, William; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In this thesis, methods to mitigate acceleration delivered to the frame of a vehicle with an attached v-shaped hull are investigated. The frame of a vehicle represents an alternative location for crew seating, as opposed to seats being secured to the floorboard. Mitigation techniques were investigated for three test setups: aluminum frame with a downwardly convex aluminum hull, steel frame with a downwardly convex steel hull, and a steel frame with a downwardly concave steel hull. Accelerations of the frame were measured using piezoelectric accelerometers placed at three different locations on the frame. These acceleration measurements were verified against video recorded by high speed cameras. Each test was intended to reduce peak accelerations experienced by the frame, and to reduce the width of the acceleration envelope at large g levels. Mitigation techniques focused on reducing the initial hull-frame interactions, while damping subsequent responses of the system. Mitigation systems and hull orientation were compared for their ability to reduce blast effects experienced by the frame.