Assessing CFD Modeling of Entropy Generation for the Air Frame Subsystem in an Integrated Aircraft Design/Synthesis Procedure

2006 ◽  
Author(s):  
Ken Alabi ◽  
Foluso Ladeinde ◽  
Mike vonSpakovsky ◽  
David Moorhouse ◽  
Jose Camberos
Keyword(s):  
Entropy Generation ◽  
Aircraft Design ◽  
Cfd Modeling ◽  
Design Synthesis ◽  
Synthesis Procedure

A Negative Impedance Approach to the Design Synthesis and Control of Multi-Energy Active Elements

2005 ◽  
Author(s):  
Thomas J. Connolly
Keyword(s):  
Control System ◽  
Synthesis Method ◽  
Design Tool ◽  
Electric Motors ◽  
Active Device ◽  
Design Synthesis ◽  
System Architectures ◽  
Active Devices ◽  
Synthesis Procedure ◽  
And Control

This paper covers the continuing development and experimental validation of our approach to the design synthesis and control of active devices in dynamic mechanical systems. Active devices, such as electric motors and hydraulic actuators, require an external power input. An innovative feature of this synthesis approach is the use of non-physically realizable elements, i.e., elements that have negative impedances, to model the behavior of an active device. The synthesis method also features the use of bond graphs, as they facilitate modeling of multi-energy systems and devices. The procedure applies to the design or retrofit of systems for which a desired frequency response is prescribed. The overarching goal of the synthesis method is to yield options for the general framework of a controllable, stable, and parameterizable system, using simulation-based techniques. Thus the procedure yields a stable “first draft” of the active device and its control system that can be handed off to respective specialists for further refinement. Simulation results indicate that design possibilities can include purely active devices or a hybrid combination of active and passive elements. In addition, atypical control system architectures, that depart from traditional PI, PD, or PID controllers can arise from the synthesis procedure. We describe validation experiments that use electric motors and rack-and-pinion systems to achieve active control of a quarter-vehicle test article. The results will provide insight into: (1) refining the synthesis procedure to include systems that feature continuous elements, (2) partially automating the synthesis procedure to make it a more versatile design tool, and (3) practical limitations of the synthesis method.

Future strike aircraft design synthesis

1981 ◽  
Author(s):  
R. SCHAEFER, JR. ◽  
R. SMITH
Keyword(s):  
Aircraft Design ◽  
Design Synthesis

Epitaxy and texture analysis of Bi-Sr-Ca-Cu-O thin films on (100) MgO using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 68-69
Author(s):  
J. T. Sizemore ◽  
D. G. Schlom ◽  
Z. J. Chen ◽  
J. N. Eckstein ◽  
I. Bozovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Critical Currents ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Cell Axis ◽  
Transmission Electron ◽  
Synthesis Procedure

Investigators observe large critical currents for superconducting thin films deposited epitaxially on single crystal substrates. The orientation of these films is often characterized by specifying the unit cell axis that is perpendicular to the substrate. This omits specifying the orientation of the other unit cell axes and grain boundary angles between grains of the thin film. Misorientation between grains of YBa2Cu3O7−δ decreases the critical current, even in those films that are c axis oriented. We presume that these results are similar for bismuth based superconductors and report the epitaxial orientations and textures observed in such films.Thin films of nominally Bi2Sr2CaCu2Ox were deposited on MgO using molecular beam epitaxy (MBE). These films were in situ grown (during growth oxygen was incorporated and the films were not oxygen post-annealed) and shuttering was used to encourage c axis growth. Other papers report the details of the synthesis procedure. The films were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM).

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