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Technical Paper

Fatigue Testing of Corrugated and Teflon Hoses

1990-07-01
901436
In order to test the resilience of flexible hoses to bending stress, a test assembly was constructed to determine the number of flexing cycles the hoses could withstand before losing their ability to maintain a constant pressure. ...Corrugated metal hoses of 1/4, 3/8, and 1/2-inch diameter and teflon hoses of 3/8 (smooth bore) and 1/2-inch (convoluted) diameter were tested at different pressures with nitrogen gas. The metal hoses had lives ranging from 30,000 to 100,000 flexing cycles. ...The purpose of this study was to determine by means of testing whether flexible hoses, either teflon or corrugated metal, were capable of withstanding the large number of flexes that would be experienced on a long-term space facility.
Technical Paper

Further Considerations of a Theory of Crack Propagation in Metal Fatigue

1963-01-01
630386
Substantial modifications have been made to a theory of metal fatigue proposed earlier by Valluri. Modifications are concerned with the nature of crack growth, the appropriate stresses that should be used in discussion of the crack growth, and a discussion of the internal stresses that are presumed to oppose the motion of dislocations. ...Some results of the modifications are (1) Stress distribution at the tip of the crack is dependent upon the natural plastic stress concentration factor, gross stress, and the crack length; (2) The effect of decrease in internal stresses gives rise to the concept of a “nucleation period” in low stress level fatigue; (3) Rate of crack growth is strongly dependent upon the net section stress, the stress ratio, and the plastic stress concentration factor.
Book

Fatigue and Durability of Structural Materials

2006-03-01
The major emphasis is on fatigue and failure behavior using engineering models that have been developed to predict, in advance of service, acceptable fatigue and other durability-related lifetimes. ...The major emphasis is on fatigue and failure behavior using engineering models that have been developed to predict, in advance of service, acceptable fatigue and other durability-related lifetimes. Information covers broad classes of materials used for high-performance structural applications such as aerospace components, automobiles, and power generation systems.
Technical Paper

DESIGN FOR FATIGUE

1954-01-01
540226
The gross area stress is also a better basis than the 1.0g operating stress level for comparing fatigue life in similar aircraft. 4. Step testing to check design quality. This preferred method of fatigue testing is discussed here. ...This preferred method of fatigue testing is discussed here....STEPS in fatigue design of aircraft lower wing surfaces, as presented here, are: 1. Selecting a structure that permits easy fatigue-crack detection.
Standard

Coupling Assembly, V-Band Sheet Metal Wide Flange, Pneumatic Tube

2017-12-12
CURRENT
AS6369
This SAE Aerospace Standard (AS) establishes the requirements for a grooved clamp coupling and flanges suitable for joining intermediate pressure and temperature ducting in aircraft pneumatic systems. The coupling joint assembly, hereafter referred to as "the joint", shall operate within the temperature range of -65 °F external ambient to +800 °F internal fluid.
Standard

Coupling Assembly, V-Band, Sheet Metal Flange, Pneumatic Tube

2013-01-02
CURRENT
AS1960
This specification defines the requirements for a grooved clamp coupling and flanges suitable for joining intermediate pressure and temperature ducting in aircraft air systems. The rigid coupling joint assembly, hereafter referred to as "the joint", shall operate within the temperature range of -65 °F to +800 °F.
Standard

Coupling Assembly, V-Band Sheet Metal Wide Flange, Pneumatic Tube

2013-01-07
CURRENT
AS4751
This SAE Aerospace Standard (AS) establishes the requirements for a grooved clamp coupling and flanges suitable for joining intermediate pressure and temperature ducting in aircraft pneumatic systems. The rigid coupling joint assembly, hereafter referred to as “the joint”, shall operate within the temperature range of -65 °F external ambient to +800 °F internal fluid.
Book

Accelerated Testing

2006-03-27
In Accelerated Testing: A Practitioner's Guide to Accelerated and Reliability Testing, readers are exposed to the latest, most practical knowledge available in this dynamic and important discipline. ...Development and quality assurance tests are defined in detail and are presented from a practical viewpoint. Included are testing fundamentals, plans and models, and equipment and methods most commonly used in accelerated testing. ...The application of accelerated testing theory is a difficult proposition, yet one that can result in considerable time and cost savings, as well as increasing a product's useful life.
Technical Paper

Fatigue Testing of Full-Scale All-Composite Aircraft Wings

1987-11-13
872459
A full scale fatigue test program has been established which will test a sailplane wing set to destruction. A flight loads data acquisition program using the instrumented high performance sailplane owned by the Royal Melbourne Institute of Technology has been conducted to determine the loading cases and spectrum. ...One wing was new at the commencement of the fatigue test, while the other is a repaired wing salvaged from a damaged sailplane. The test of the repaired wing will enable the fatigue performance of repair techniques to be evaluated. ...In parallel with the full scale fatigue test, tests on notched and plain glass fibre specimens will be used to establish material scatter factors which can be employed in safe fatigue life estimation.
Technical Paper

Thermal Fatigue Testing of Simulated Turbine Blades

1971-02-01
710459
This caused a substantial reduction in thermal fatigue life. Coating effectiveness was below that for low velocity tests....Crack initiation and propagation data were obtained for a variety of test conditions. The simulated turbine blades consisted of coated and uncoated IN 100 and B 1900 cambered airfoils with grips for application of spanwise load to simulate centrifugal stress. ...The simulated turbine blades consisted of coated and uncoated IN 100 and B 1900 cambered airfoils with grips for application of spanwise load to simulate centrifugal stress. Test variables were blade temperature, spanwise load, and steady-state (hold) time. The Mach 1 gas velocity substantially reduced conventional creep rupture life.
Book

Fatigue and Durability of Metals at High Temperatures

2009-07-01
From concept to application, Fatigue and Durability of Metals at High Temperatures describes the method of strain-range partitioning for analyzing time-dependent fatigue. ...From concept to application, Fatigue and Durability of Metals at High Temperatures describes the method of strain-range partitioning for analyzing time-dependent fatigue. Creep (time-dependent) deformation is first introduced for monotonic and cyclic loading.
Standard

Flexure Fatigue Strength of Tube Fitting Joints

2020-05-06
CURRENT
AIR1418B
This SAE Aerospace Information Report (AIR) presents flexure fatigue strength of tube fitting joints in the form of graphs showing applied deflection D and total calculated axial stress S versus number of cycles to failure N. ...The graphs have been prepared from data obtained by actual testing conducted in accordance with ARP1185.
Technical Paper

Service and Testing Observations of Fatigue Failure in Helicopter Components

1954-01-01
540249
FATIGUE failure is now one of the most serious hindrances to satisfactory service life for helicopters. ...To help the industry bring the fatigue failure problem under control, these authors summarize what they have learned from studying 169 fatigue failures that occurred during 58,000 hr of helicopter flying operations. ...To help the industry bring the fatigue failure problem under control, these authors summarize what they have learned from studying 169 fatigue failures that occurred during 58,000 hr of helicopter flying operations. They have classified these failures as being caused by: 1.
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