Stories
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Briefs: Mechanical & Fluid Systems
The figure depicts an improved apparatus for three- or four-point bending tests of stripe specimens. In a bending test, the specimen is subjected to tension along its top surface and compression along its...
Briefs: Mechanical & Fluid Systems
Using Genetic Algorithms in Spacecraft Vibration Control
Three software products are being developed to help satisfy the needs of NASA and of private industry for reconfigurable active control systems to suppress vibrations in Reusable Launch Vehicles (RLVs) and other structures. These potentially highly marketable products are the following:
The...
Briefs: Mechanical & Fluid Systems
Two techniques have been proposed (see figure) for controlling the buoyancies and thus the altitudes of robotic lifting balloons (aerobots) that would carry scientific instruments...
Briefs: Mechanical & Fluid Systems
Improved pressure-relief valves have been developed for systems that contain gases and liquids in a variety of pneumatic, hydraulic, and cryogenic applications. These valves could prove...
Briefs: Mechanical & Fluid Systems
It is not necessary to allocate valuable forebody volume to strake-deployment mechanisms.
Briefs: Mechanical & Fluid Systems
Equipping Quick-Disconnect Fittings To Detect Leaks
Quick-disconnect fittings on hoses and bellows can be equipped with sensors to detect leaks and misalignments that cause leaks. Experiments have shown that four types of sensors are effective for this purpose: force sensors, strain gauges, pressure transducers, and microphones. Of these, force...
Briefs: Sensors/Data Acquisition
A surface-micromachining process has been devised for use in fabricating microscopic polycrystalline diamond structures (e.g., bridges and cantilevers) as integral parts...
Briefs: Mechanical & Fluid Systems
This airplane is expected to be safe from destruction by flutter instabilities.
Briefs: Mechanical & Fluid Systems
A prototype Stirling-engine regenerator containing a matrix made of carbon-fiber-based composite materials has been developed. The concept underlying this development effort is one of...
Briefs: Mechanical & Fluid Systems
A flutterometer is being developed for use as a data-analysis tool for flight flutter testing. The tool is based on an on-line implementation of a robust flutter-analysis technique, called the "* method," that...
Briefs: Mechanical & Fluid Systems
A mathematical model represents the dynamic response of a pressure sensor that (a) comprises a transducer connected to a pressure-sensing port via a pneumatic tube and (b) is operated under...
Briefs: Mechanical & Fluid Systems
Improved Mufflers for General Aviation
Innovative designs of mufflers for engines of small airplanes have been investigated in an effort to satisfy conflicting demands to maximize the reduction of exhaust noise while minimizing back pressure, size, and weight. Automotive-type muffler designs are not suitable for this purpose because they entail...
Briefs: Mechanical & Fluid Systems
An acoustic-radiation-pressure phased array (ARPPA) is undergoing development at Lewis Research Center. ARPPAs are envisioned as general-purpose, nonintrusive tools for manipulating both liquids...
Briefs: Mechanical & Fluid Systems
Structural Analysis/Design (STRAND) and Neural Net Computation (NETCOM) are developmental modular computer programs that exploit the speedup afforded by parallel and neural-network...
Briefs: Mechanical & Fluid Systems
Acoustic-radiation pressure can be used to improve performance in the dispensing of liquid drops into gases or vacuum and in dispensing gas bubbles into liquids. In a typical application...
Briefs: Mechanical & Fluid Systems
Harmonic drive gearing is recognized by designers for its zero backlash, high gear ratios, and compact design features. A recent development by HD Systems incorporates a large hollow shaft...
Briefs: Mechanical & Fluid Systems
An improved "sensor-integrating" algorithm has been developed for use in extracting partial information on the time-varying attitude of a balloon-borne robotic instrumentation system...
Briefs: Mechanical & Fluid Systems
Latching devices have been developed to provide electrical connections, secure mechanical and thermal connections, and optical alignment for mounting electronically controlled cameras...
Briefs: Mechanical & Fluid Systems
Window assemblies (see figure) have been developed to satisfy special requirements pertaining to ease of replacement, alignment, sealing, and resistance to vibration in a spaceborne...
Briefs: Mechanical & Fluid Systems
A two-body design has enabled an instrumented penetrator projectile to function with increased tolerance to initial misalignment among (a) the longitudinal axis of the penetrator, (b) the...
Briefs: Mechanical & Fluid Systems
Magnetostatic switches — switches that open or close in response to magnetic fields — are being developed and fabricated using micromachining (MEMS) technology. These switches operate similarly to...
Briefs: Mechanical & Fluid Systems
Multifinger electroactive-polymer grippers (MEPGs) are simple, compact, lightweight robotic end effectors with fingers that bend and function similarly to human fingers. The fingers are made from...
Briefs: Mechanical & Fluid Systems
A novel airdata system based on flush-mounted pressure sensors has been developed for the X-33 aerospace vehicle. Denoted the "X-33 flush airdata sensing" (FADS) system, it was...
Briefs: Mechanical & Fluid Systems
Program Facilitates Simulation of Flows of Cryogenic Fluids
EASY/ROCETS is a developmental computer program for mathematical modeling and analysis of dynamic flows of cryogenic fluids in a rocket-engine-testing facility. Heretofore, the numerical simulation of such flows has been accomplished by use of computer codes specific to test-equipment...
Briefs: Mechanical & Fluid Systems
Updated Program for Computing Stresses in Spur Gears
DANST-PC is version 3.01 of a computer program for analysis of the statics and dynamics of spur-gear systems. ["DANST" signifies "Dynamic Analysis of Spur Gear Transmissions." A previous version was described in "Computing Stresses in Spur Gears," NASA Tech Briefs, Vol. 19, No. 12 (December...
Briefs: Mechanical & Fluid Systems
Devices are proposed that would sublime solid propellants to generate small thrusts for maneuvering spacecraft with masses of no more than 15 kg. With solids rather than gases in propellant tanks, there would be...
Briefs: Mechanical & Fluid Systems
The figure illustrates a device that flexes to allow rotation about a single axis through a total range of ±12°. This device was designed to offer the following advantages over commercial flexural pivots:
Briefs: Mechanical & Fluid Systems
Automatic valves have been proposed for shutting off flows of liquids when abnormally large accelerations occur. These valves could be used, for example, to prevent outflows of...
Briefs: Mechanical & Fluid Systems
The Spacecraft Autonomous Navigation System using GPS for Earth Orbiters (SANS-GEO) computer program is designed to perform the navigation calculations that will enable the New...
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