A. James Clark School of Engineering
Permanent URI for this communityhttp://hdl.handle.net/1903/1654
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Small-Scale Testing to Study Mitigation of Acceleration on Simulated Vehicles(2013) Bonsmann, Jarrod; Fourney, William L; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation investigates various means for mitigating acceleration experienced by passengers on vehicles subjected to blast loading. In order to complete this study, small-scale testing of simulated vehicles was used. The explosives designated for this research are exclusively buried in saturated sand, which will act as the loading media for the simulated vehicles. In addition to explosive testing, various tests were performed dynamically using a high-pressure gas gun. Initially, tests were performed to better understand the effects of vehicle mass and stand-off distance on vehicle acceleration due to blast loads; after which, studies were conducted to mitigate the acceleration. Test plates used in this study vary in both size and geometry. When necessary, simple plate geometries are employed to investigate various mitigation parameters. Ultimately, much of the testing was conducted on simplified scaled versions of vehicles likely to be subjected to attack. This paper focuses mainly on mitigation through crushing of thin-walled cylinders, but also investigates the advantages of applying polymeric coatings to dynamically loaded structures. Piezoelectric accelerometers are used in conjunction with high speed videography to collect test data. In addition to acceleration, impulse and kinetic energy of each test plate is examined. This research, though funded by the US Army, will be of use to all branches of the armed forces utilizing Mine-Resistant Ambush-Protected vehicles. The ultimate goal of this research is to help create a vehicle that will increase the probability that the passengers will survive a blast event with minimal long-term damage to the brain.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.