107 research outputs found
Quiet Clean Short-haul Experimental Engine (QCSEE) under-the-wing engine composite fan blade design report
A total of 38 quiet clean short haul experimental engine under the wing composite fan blades were manufactured for various component tests, process and tooling, checkout, and use in the QCSEE UTW engine. The component tests included frequency characterization, strain distribution, bench fatigue, platform static load, whirligig high cycle fatigue, whirligig low cycle fatigue, whirligig strain distribution, and whirligig over-speed. All tests were successfully completed. All blades planned for use in the engine were subjected to and passed a whirligig proof spin test
Impact absorbing blade mounts for variable pitch blades
A variable pitch blade and blade mount are reported that are suitable for propellers, fans and the like and which have improved impact resistance. Composite fan blades and blade mounting arrangements permit the blades to pivot relative to a turbine hub about an axis generally parallel to the centerline of the engine upon impact of a large foreign object, such as a bird. Centrifugal force recovery becomes the principal energy absorbing mechanism and a blade having improved impact strength is obtained
Program for impact testing of spar-shell fan blades, test report
Six filament-wound, composite spar-shell fan blades were impact tested in a whirligig relative to foreign object damage resulting from ingestion of birds into the fan blades of a QCSEE-type engine. Four of the blades were tested by injecting a simulated two pound bird into the path of the rotating blade and two were tested by injecting a starling into the path of the blade
Neutron Drops and Skyrme Energy-Density Functionals
The J=0 ground state of a drop of 8 neutrons and the lowest
1/2 and 3/2 states of 7-neutron drops, all in an external well, are
computed accurately with variational and Green's function Monte Carlo methods
for a Hamiltonian containing the Argonne two-nucleon and Urbana IX
three-nucleon potentials. These states are also calculated using Skyrme-type
energy-density functionals. Commonly used functionals overestimate the central
density of these drops and the spin-orbit splitting of 7-neutron drops.
Improvements in the functionals are suggested
Stability of the mixed phase in hybrid stars
The transition from hadronic matter to quark matter in the core of neutron
stars is likely to be associated with the appearance of a mixed phase, leading
to a smooth variation of the star density profile. We discuss the results of a
systematic study of the properties of the mixed pase upon Coulomb and surface
effects. A state of the art nonrelativistic equation of state of nuclear matter
has been used for the low density phase, while quark matter has been described
within the MIT bag model, including the effect of perturbative one-gluon
exchange interactions. The implications for neutron star structure are
discussed.Comment: Submitted to Astronomy & Astrophysic
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