Fail-safe hydraulic shaker protection
Nine channel system controls acceleration and force on structure undergoing vibration stress testing. System has automatic and manually operative abort feature.
Woodbury, R. C.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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A reliability-based cost effective fail-safe design procedure
The authors have developed a methodology for cost-effective fatigue design of structures subject to random fatigue loading. A stochastic model for fatigue crack propagation under random loading has been discussed. Fracture mechanics is then used to estimate the parameters of the model and the residual strength of structures with cracks. The stochastic model and residual strength variations have been used to develop procedures for estimating the probability of failure and its changes with inspection frequency. This information on reliability is then used to construct an objective function in terms of either a total weight function or cost function. A procedure for selecting the design variables, subject to constraints, by optimizing the objective function has been illustrated by examples. In particular, optimum design of stiffened panel has been discussed.
Hanagud, S.↗
Safe venting for electronic components
Vented enclosure is made from lightweight metal. Printed-circuit boards are attached to bottom and end bulkheads and to top cover. Airflow cools components indirectly through walls of inner compartment. Flammability and smoke tests demonstrate safety of enclosure.
Currin, R., Jr.↗
Safe, durable soil sampler
Soil sampling tool protects user from injury and resists effects of weather and hard use. Penetrometer has uses in construction, surveying, geological research and similar applications.
Durrant, R. D.↗
Extra-safe tractor-trailer coupling
Built-in safety mechanism for tractor-trailer "fifth-wheel" coupling keeps rig together in case kingpin failure. Modified coupling utilizes all standard components, such as two wear plates, kingpin, and kingpin latch. It is modified by adding semicircular lip to top wear plate, matching semicircular slot to bottom wear plate, and two latching stop mechanisms.
Albrecht, W. P.↗
Safe bending of boron/aluminum sheets
Low cost procedure utilizing aluminum backing sheets protects boron/aluminum sheet from cracking during bending. Process utilizes inexpensive universal-brake bending dies rather than special hydroforming dies.
Liskay, G. G.↗
Safely splicing glass optical fibers
Field-repair technique fuses glass fibers in flammable environment. Apparatus consists of v-groove vacuum chucks on manipulators, high-voltage dc power supply and tungsten electrodes, microscope to observe joint alignment and fusion, means of test transmission through joint. Apparatus is enclosed in gas tight bos filled with inert gas during fusion. About 2 feet of fiber end are necessary for splicing.
Korbelak, K.↗
Oxygen levels safe for continued reproduction of Drosophila in normal and hypobaric atmospheres
Explore the source record for details and available documents.
Kloek, G. P.↗
Regulating Oxygen Pressure Safely
Pressure regulator for oxygen allows gas flow shut off on low-pressure (outlet) side rather than high-pressure (inlet) side. In modified pressure regulator initial rush of oxygen occurs in second stage rather than first stage of pressure reduction. Large volume of second stage prevents excessive heating of gas. High-pressure source remains on, and first stage reamins pressurized at all times. New regulator reduces danger of fire in aircraft and in medical oxygen supplies.
Simons, C.↗
Solar Array Flight Experiment (SAFE)
The solar arrays flight experiment consists of four experiments on two different flights. The first experiment, termed the baseline, has a basic purpose to demonstrate the flight readiness of lightweight solar array technology for solar electric propulsion and other payload power applications. The early availability of this experiment and its basic large space structure characteristics make it a logical candidate to demonstrate other disciplines critical to large space structures. These demonstrations form the basis for three other solar array experiments, two in remote sensing and one in control. All of these experiments are briefly reviewed in this paper.
Schock, R. W.↗
Fatigue analysis of composite materials using the fail-safe concept
If R1 is the probability of having a crack on a flight component and R2 is the probability of seeing this crack propagate between two scheduled inspections, the global failure regulation states that this product must not exceed 0.0000001.
Stievenard, G.↗
Low-drag ground vehicle particularly suited for use in safely transporting livestock
A low-drag truck consisting of a tractor-trailer rig characterized by a rounded forebody and a protective fairing for the gap conventionally found to exist between the tractor and the trailer is described. The fairing particularly suited for establishing an attached flow of ambient air along its surfaces. The truck is also comprised of a forward facing, ram air inlet and duct and a plurality of submerged inlets and outflow ports communicating with the trailer for continuously flushing heated gases from the trailer as the rig is propelled at highway speeds.
Saltzman, E. J.↗
Safe Emergency Evacuation From Tall Structures
Emergency egress system allows people to be evacuated quickly from tall structures. New emergency system applicable to rescues from fires in tall hotels and other buildings. System consists of basket on slide wire. Basket descends by gravity on sloped slide wire staked to ground.
Stephan, E. S.↗
Safe structures for future aircraft
The failure mechanisms, design lessons, and test equipment employed by NASA in establishing the airworthiness and crashworthiness of aircraft components for commercial applications are described. The composites test programs have progressed to medium primary structures such as stabilizers and a vertical fin. The failures encountered to date have been due to the nonyielding nature of composites, which do not diffuse loads like metals, and the presence of eccentricities, irregular shapes, stiffness changes, and discontinuities that cause tension and shear. Testing to failure, which always occurred in first tests before the design loads were reached, helped identify design changes and reinforcements that produced successful products. New materials and NDE techniques are identified, together with aircraft structural design changes that offer greater protection to the passengers, fuel antimisting agents, and landing gear systems.
Mccomb, H. G., Jr.↗
Safe havens: Selecting landing sites for Viking
The involved process by which a landing site on the Martian surface was selected for the Viking lander spacecraft is reviewed. Spacecraft survivability had to be weighed against having the lander touch down in an area of little scientific value. The mission of Mariner 9 is discussed and imagery of Mars generated by this space probe is presented.
Source record↗
Wing contamination - Threat to safe flight
Attention is given to the initial results of systematic investigations of the potentially hazardous effect of heavy rain, ice, and frost accretion on aircraft wings. In the laminar region of an airfoil, roughness interferes with smooth flow and tends to encourage transition from laminar to turbulent flow upstream of its normal point of occurrence. In the airfoil's turbulent region, roughness considerably worsens the turbulent friction coefficient, thereby increasing the drag coefficient. Consequent dramatic decreases of maximum lift coefficient at high angles of attack lead to premature stall. Such decreases in stall angle destroy the safety margin of an aircraft approaching stall. An assessment is given to the state of knowledge in this field of research.
Luers, J. K.↗
Operating safely in adverse weather environments
NASA has undertaken three research programs since 1974 that are concerned with the gathering of flight data under adverse and potentially severe weather conditions, such as wind shear, wind turbulence, icing, hail, rain, and lightning. All six conditions may be present in a given storm formation. Attention is presently given to the B-57B, DHC-6, and F-106B research aircraft employed by these flight data gathering efforts, and the accumulated experience with prediction, remote sensing and weather system penetration methods is discussed. Research results are compared with airliner data for 1970-1975. Evidence is found for two electrically active charge centers in thunderstorms, one of which lies at altitudes whose temperature is near the freezing level, and another at higher altitudes, in the temperature range from -25 to -35 C.
Stickle, J. W.↗
Power-Factor Controllers: How Safe?
Potential safety problems with power-factor controllers (PFC's) evaluated. Based on study of PFCs in use with appliances, report recommends measures to prevent consumers from misapplying these energy saving devices. Device used on such appliances as refrigerators, sewing machines, pumps, hair dryers, and food processors. When misused, they fail to save energy and may cause damage.
Long, K.↗