Speed Degradation Research Articles

Flutter Speed Degradation of Damaged, Optimized Flight Vehicles

A STUDY of the effects of mass and stiffness changes on the flutter degradation of optimized wings is presented in this paper. The wings were optimized for weight with constraints on strength, displacement, and flutter speed. The mass and stiffness changes are representative of battle damage. The structural box is idealized by finite elements consisting of membranes, shear panels, and bar elements. The aerodynamic force matrix is generated by incompressible strip theory. Five damage models involving two wing boxes are included. The effect of damage on aerodynamic flow is not treated.

The use of non-uniformly doped FETs in GaAs subnanosecond switching circuits : simulations

Subnanosecond switching circuits employing a proposed new non-uniformly doped junction field effect transistor (NUDJFET) are simulated and compared to simulated and published experimental test results of similar configurations employing uniformly doped devices. The non-uniform channel doping of the NUDJFET octs to lower its saturation voltage, thus allowing a given circuit configuration to operate at a lower power supply voltage with very little speed degradation and hence a reduced speed-power product. Several important switching circuit configurations are simulated and their speed and power performances compared and evaluated.

Design and operation of a vacuum cathodic etching unit: W N Wise,National Lead Co, Cincinatti, Ohio, May 1966, 16 pages

The radial-type superconducting magnetic bearing (SMB) system consists of the superconducting stator (SC stator) and the permanent magnet rotor (PM rotor). The rotation speed degradation of the PM rotor is one of the most significant problems for the practical use of SMB to the energy storage flywheel system. This phenomenon is caused mainly by the eddy current in the PM rotor induced by the inhomogeneous magnetic field which is weakened at the joints between the YBCO bulks. In this research, the rotation speed degradation and the rotation energy loss were simulated, and their suppression effect was evaluated by the 3-dimensional superconducting current simulation code based on the current vector potential method (T-method) and the vector potential method (A–ϕ method) [K. Demachi, R. Numata, R. Shimizu, K. Miya, H. Higasa, J. Mater. Process Technol. 108 (2001) 141].

Space molecular sink simulator facility design: J B Stephens,Rep NASA-CR-74654; JPL-TR-32-901 March 1966 ( Jet Propulsion Lab, Calif Inst of Tech, Pasadena)

The radial-type superconducting magnetic bearing (SMB) consists of the superconducting stator (SC stator) and the permanent magnet rotor (PM rotor). The rotation speed degradation of the PM rotor is one of the most significant problems for the practical use of SMB to the energy storage flywheel system. This phenomenon is thought to be caused by the eddy current in the PM rotor induced by the magnetic field of the SC stator which is inhomogeneous because the SC stator does not consist of a single superconductor bulk. In this research, the rotation speed degradation of 100 kW h flywheel was simulated by the 3-dimensional superconducting current simulation code.