Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"impact event"”.
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Alamo impact event, Late Devonian, Nevada: crater phenomena and distal products
Includes bibliographical references.
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The Chicxulub impact event and the environmental catastrophe at the end of the Cretaceous Period
Impact events may have affected the evolution of life on Earth. The mass extinction event at the end of the Cretaceous Period, which includes the demise of the dinosaurs, has been linked to the large impact event that produced the Chicxulub structure located in the Yucatán Peninsula, Mexico. …
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A laboratory simulation of low velocity projectile impact on thin plates
… that will both accurately simulate a projectile impact event and provide an accurate means of analysing a material response to projectile impact events. A low velocity apparatus, based on the conventional instrumented drop tower apparatus, was designed and constructed. The apparatus is …
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A Geophysical Investigation Of The Northeastern Rim Of The St. Martin Impact Structure, Manitoba, Canada.
<p>The St. Martin impact structure is a 40 Km diameter structure located in Manitoba, Canada lies in featureless, glaciated terrain lacking any surface expression of an impact structure. The age of the structure has been re-determined to range between 224.3 Ma to 241.4 Ma which nullified a previous …
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Impact induced porosity of terrestrial impact craters : a gravity study of Meteor Crater.
… Crater that were induced by the crater-forming impact event. We performed a gravity survey at the crater and merged these new data with legacy gravity survey data. From the resulting merged gravity data set, we generated a reduced anomaly map and created a model to estimate the gravitational …
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Time-resolved spectroscopic characterization of ballistic impact events in polymer and nanocomposite materials
… during and immediately following a ballistic impact event is not currently well understood. The dynamic mechanical responses of materials experiencing ballistic shock-loading conditions are quite complex, with large amplitude compressions resulting in strain rates in excess of 106 s-1 and …
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HEAVY TRUCK COLLISION WITH BRIDGE PIERS
… designing a bridge pier vulnerable to vehicular impacts for an equivalent static force of 2,670-kN (600 kips) applied in a horizontal plane at a distance of 1.5 m (5.0 feet) above the ground level. The vast majority of research studies on vehicular collision with bridge piers have been carried …
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Self-healing of impact damage in vascular fiber-reinforced composites
… of a composite material after an out-of-plane impact event using vascular self-healing technologies. To date, the critical damage modes which occur during out-of-plane impact that most significantly contribute to reductions in post-impact performance have not been identified and methods for …
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Finite Element Modeling of Delamination Damage in Carbon Fiber Laminates Subject to Low-Velocity Impact and Comparison with Experimental Impact Tests Using Nondestructive Vibrothermography Evaluation
… common when composite laminates are subject to impact loading.</p> <p>Various finite element methods for analyzing delamination exist. In this research, a modeling strategy based on contact tiebreak definitions in LS-DYNA<sup>®</sup>was used. A finite element model of a low-velocity impact event …
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The Effect of a Low-Velocity Impact on the Flexural Strength and Dynamic Response of Composite Sandwiches with Damage Arrestment Devices
<p>Impact strength is one of the most important structural properties for a designer to consider, but is often the most difficult to quantify or measure. A constant concern in the field of composites is the effect of foreign object impact damage because it is often undetectable by visual …
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A Predictive Methodology for Soft Impact Damage in Jet Engines Incorporating Hybrid Composite Structures
… and composite structures, when subjected to soft impact. Bird strike onto the fan assembly is chosen as the impact event to be studied. The aim is to develop a numerical methodology capable of accurately capturing the full range of multifaceted damage in hybrid and composite structures as they …
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Perception and control of robot legged locomotion over variable terrain
… for such investigation due to the complexity of impact dynamics and the infinite variability of real terrain. To this end, we introduce the MIT Super Mini Cheetah, a small, inexpensive quadrupedal robot that can run and walk over a variety of ground types (gravel, tile, carpet, grass, etc.). …
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Safety considerations for operation of different classes of unmanned aerial vehicles in the National Airspace System
… in UAV operation: midair collision and ground impact. Event-based models were developed describing the likelihood of ground fatalities and midair collisions under several assumptions. From the models, a risk analysis was performed calculating the expected level of safety for each hazard without …
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The effects of tensile preloads on the impact response of carbon/epoxy laminates
Low velocity drop weight impact tests were conducted on carbon/epoxy laminates under various magnitudes of uniform tensile stress. The composite plates were 8 ply (+45,0,- 45,90)<sub>s</sub> laminates supported in a clamped-clamped/free-free configuration. Tensile preloads from near zero to …
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Design, fabrication, and calibration of an instrumented drop weight impact tester
… and calibration of an instrumented drop weight impact tester is described. Included in this description are all the sketches and drawings that are needed to duplicate this project, if so desired. This impact tester was built for around $23,000 less than it would have cost to buy and modify a …
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The solid particle erosion of WC-Co alloys
… the erosion of WC-Co alloys by solid particle impact erosion was undertaken to determine the mechanism by which material is removed. For this purpose a simple particle-gas stream erosion apparatus was employed. The nineteen different WC-Co alloys studied were initially characterised according …
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Seismic effects of the Caloris basin impact, Mercury
… tectonic disruption associated with the Caloris impact and have the potential to provide information on the interior structure of Mercury. The unusual disrupted terrain located directly at the antipode of the 1500-km-diameter Caloris basin could have plausibly formed as a consequence of focused …
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Behavior of Magneto-Rheological Fluids Subject to Impact and Shock Loading
… the issues concerning MR fluid behavior in impact and shock applications are relatively unknown. To investigate MR fluid properties in this regime, MR dampers were subjected to impulsive loads. A drop-tower test facility was developed to simulate the impact events. The design includes a …
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Mechanisms Of Head Injuries In Road Traffic Accidents; A Potential Solution For Data Collection
… in obtaining elusive data regarding the kind of impact events that could cause head injuries for road users. An in-ear accelerometer system used by the FIA Institute was evaluated through experimentation. Then a low-cost solution was developed with the aim to give similar sensor performance for a …
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