Publications

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Pulsed Arrested Spark Discharge (PASD) is a Sandia National Laboratories Patented, non-destructive wiring system diagnostic that has been developed to detect defects in aging wiring systems in the commercial aircraft fleet. PASD was previously demonstrated on relatively controlled geometry wiring such as coaxial cables and shielded twisted-pair wiring through a contract with the U.S. navy and is discussed in a Sandia National Laboratories report, SAND2001-3225 ''Pulsed Arrested Spark Discharge (PASD) Diagnostic Technique for the Location of Defects in Aging Wiring Systems''. This report describes an expansion of earlier work by applying the PASD technique to unshielded twisted-pair and discrete wire configurations commonly found in commercial aircraft. This wiring is characterized by higher impedances as well as relatively non-uniform impedance profiles that have been found to be challenging for existing aircraft wiring diagnostics. Under a three year contract let by the Federal Aviation Administration, Interagency Agreement DTFA-03-00X90019, this technology was further developed for application on aging commercial aircraft wiring systems. This report describes results of the FAA program with discussion of previous work conducted under U.S. Department of Defense funding.

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The Radiatively Driven Hypersonic Wind Tunnel (RDHWT) program requires an unprecedented 2-3 MeV electron beam energy source at an average beam power of approximately 200MW. This system injects energy downstream of a conventional supersonic air nozzle to minimize plenum temperature requirements for duplicating flight conditions above Mach 8 for long run-times. Direct-current electron accelerator technology is being developed to meet the objectives of a radiatively driven Mach 12 wind tunnel with a free stream dynamic pressure q=2000 psf. Due to the nature of research and industrial applications, there has never been a requirement for a single accelerator module with an output power exceeding approximately 500 kW. Although a 200MW module is a two-order of magnitude extrapolation from demonstrated power levels, the scaling of accelerator components to this level appears feasible. Accelerator system concepts are rapidly maturing and a clear technology development path has been established. Additionally, energy addition experiments have been conducted up to 800 kW into a supersonic airflow. This paper will discuss progress in the development of electron beam accelerator technology as an energy addition source for the RDHWT program and results of electron beam energy addition experiments conducted at Sandia National Laboratories.

The potential of a new cable diagnostic known as Pulse-Arrested Spark Discharge technique (PASD) is being studied. Previous reports have documented the capability of the technique to locate cable failures using a short high voltage pulse. This report will investigate the impact of PASD on the sample under test. In this report, two different energy deposition experiments are discussed. These experiments include the PASD pulse ({approx}6 mJ) and a high energy discharge ({approx}600 mJ) produced from a charged capacitor source. The high energy experiment is used to inflict detectable damage upon the insulators and to make comparisons with the effects of the low energy PASD pulse. Insulator breakdown voltage strength before and after application of the PASD pulse and high energy discharges are compared. Results indicate that the PASD technique does not appear to degrade the breakdown strength of the insulator or to produce visible damage. However, testing of the additional materials, including connector insulators, may be warranted to verify PASDs non-destructive nature across the full spectrum of insulators used in commercial aircraft wiring systems.