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Clearfield, UT, United States

Kelly P.B.,Hill Air force Base
AUTOTESTCON (Proceedings) | Year: 2012

Testing involves applying stimulus to a device, called the Unit Under Test (UUT), and evaluating the measured response against the expected values. Traditional systems use discrete instruments to supply the stimulus and measure the response, but most devices are part of a larger system and may be a component of a closed control loop. Many devices are designed to respond to the inputs by generating outputs that are dependent on some part of the output being fed back to the inputs through the rest of the system. To be comprehensive, a test of such a device must include stimulus and response that matches, as closely as possible, the way the device is used in the full system. This requires test equipment that can alter the stimulus in response to the UUT's outputs. For low speed systems, software can often accomplish this, which is the traditional approach, but systems that require much faster response than practically accomplished in software are simply not tested in this fashion unless custom test hardware is designed to do it. This drives up the cost of test station and test program design, development, and maintenance, making it prohibitive except where crucial. © 2012 IEEE. Source

Chase B.,Hill Air force Base
AUTOTESTCON (Proceedings) | Year: 2014

The Air Force A-10C attack aircraft is currently experiencing obsolescence issues with its legacy support equipment. The Portable Automated Test Station Model 70 (PATS-70) replaces over a dozen pieces of obsolete and irreparable flightline support equipment. The PATS-70 is a robust, flightline qualified test set that has gone through rigorous MIL-STD-810G, and MIL-STD-416F environmental testing. While it was developed to function as maintenance support equipment for the A-10C aircraft, it has no A-10 specific components so it can be adapted for maintenance on other aircraft, platforms, or systems. This paper describes the history of the PATS-70 and discusses the advantages to using it to maintain systems throughout the Department of Defense. © 2014 IEEE. Source

Warner J.J.,Hill Air force Base | Clark P.N.,Southwest Research Institute | Hoeppner D.W.,University of Utah
International Journal of Fatigue | Year: 2014

The increased number of aging aircraft in operation today requires a deeper understanding of fatigue life improvement methods. This research focused on the fatigue life benefit from cold expanded holes with preexisting cracks approximately 1.270 mm (0.050 in.) long under constant amplitude and wing spectrum loading. Holes with preexisting cracks were tested to simulate the worst case scenario of a hole with a crack the size of the detection threshold, 1.270 mm (0.050 in.), present before cold expansion that was not found by Non Destructive Inspection. Test results were compared to crack growth models generated in AFGROW. At high stress levels the AFGROW models yielded non conservative results greater than 150% of the test demonstrated fatigue life. Source

Dunkley R.,Hill Air force Base
AUTOTESTCON (Proceedings) | Year: 2012

Supporting a variety of communication protocols for test support equipment has typically required extensive hardware and Input/Output (I/O) interfaces targeting each protocol specifically. Recent advanced designs in the past ten years have created more dynamic approaches by using Field Programmable Gate Arrays (FPGAs) and embedded hardware to implement or simulate previous hardware I/O designs. The dynamic possibilities of FPGAs have recently been expanded with the introduction of Dynamic Partial Reconfiguration (DPR), which allows part of the FPGA to be reconfigured while the rest of the logic remains static. This paper evaluates the advantages and disadvantages of using DPR to interface with various communication protocols in test equipment. © 2012 IEEE. Source

Ligrani P.,University of Oxford | Ligrani P.,Hill Air force Base | Goodro M.,University of Oxford | Goodro M.,Saint Louis University | And 2 more authors.
Journal of Heat Transfer | Year: 2013

Experimental results are presented for a full-coverage film cooling arrangement which simulates a portion of a gas turbine engine, with appropriate streamwise static pressure gradient. The test surface utilizes varying blowing ratio (BR) along the length of the contraction passage which contains the cooling hole arrangement. For the different experimental conditions examined, film cooling holes are sharp-edged and streamwise inclined either at 20 deg or 30 deg with respect to the liner surface. The film cooling holes in adjacent streamwise rows are staggered with respect to each other. Data are provided for turbulent film cooling, contraction ratios of 1, 3, 4, and 5, blowing ratios (at the test section entrance) of 2.0, 5.0, and 10.0, coolant Reynolds numbers Refc of 10,000-12,000, freestream temperatures from 75 °C to 115 °C, a film hole diameter of 7 mm, and density ratios from 1.15 to 1.25. Nondimensional streamwise and spanwise film cooling hole spacings, X/D and Y/D, are 6, and 5, respectively. When the streamwise hole inclination angle is 20 ° spatially averaged and line-averaged adiabatic effectiveness values at each x/D location are about the same as the contraction ratio varies between 1, 3, and 4, with slightly higher values at each x/D location when the contraction ratio Cr is 5. For each contraction ratio, there is a slight increase in effectiveness when the blowing ratio is increased from 2.0 to 5.0 but there is no further substantial improvement when the blowing ratio is increased to 10.0. Overall, line-averaged and spatially averaged-adiabatic film effectiveness data, and spatially averaged heat transfer coefficient data are described as they are affected by contraction ratio, blowing ratio, hole angle , and streamwise location x/D. For example, when = 20 deg, the detrimental effects of mainstream acceleration are apparent since heat transfer coefficients for contraction ratios Cr of 3 and 5 are often higher than values for Cr = 1, especially for x/D > 100. © 2013 by ASME. Source

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