"June 1999"
Topics: FATIGUE (MECHANICS), FRETTING
Source: half
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96
Oct 8, 2015
10/15
by
Kirkpatrick, Gary W.
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"June 1999"
Topic: FATIGUE (MECHANICS),FRETTING
211
211
Apr 27, 2022
04/22
by
RTÉ Radio, Drama On One
audio
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Strutting and Fretting Written and performed by Chris McHallem The play is set on the last night of a spectacularly unsuccessful tour of Macbeth, as the lead actor sits in his dressing room, trying to work out where it all went wrong. Balancing his own disappointments with a fervent appreciation of Shakespeare’s genius, he touches on such subjects as the death of Trotsky, theatre etiquette and the working methods of medieval witches. The radio version is adapted from the stage...
Topics: Chris Mc Hallem, Strutting And Fretting, Radio Drama
Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM, CHROMIUM, FRETTING CORROSION, PROTECTIVE COATINGS,...
The Problems of Fretting People
Topics: The Problems of Fretting People, Bethel Missionary Baptist Church
241
241
May 22, 2011
05/11
by
Sturms, Francis M., Jr.; Dias, William C.; Nakata, Albert Y.; Tai, Wallace S
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The Mars Pathfinder Project plans a December 1996 launch of a single spacecraft. After jettisoning a cruise stage, an entry body containing a lander and microrover will directly enter the Mars atmosphere and parachute to a hard landing near the sub-solar latitude of 15 degrees North in July 1997. Primary surface operations last for 30 days. Cost estimates for Pathfinder ground systems development and operations are not only lower in absolute dollars, but also are a lower percentage of total...
Topics: AIRCRAFT STRUCTURES, DAMAGE ASSESSMENT, DEBRIS, FAILURE ANALYSIS, LOADS (FORCES), COEFFICIENT OF...
Fretting corrosion was first noted on Shuttle flight STS-26. This flight was the first usage of the Redesigned Solid Rocket Motor (RSRM). The occurrence of fretting has since been observed on both the field and factory joints of the RSRM. Fretting is a form of corrosion that occurs at the interface between contacting, highly loaded, metal surfaces when exposed to slight relative vibratory motions. The engineering effort performed to evaluate the effect of fretting on the RSRM case hardware is...
Topics: NASA Technical Reports Server (NTRS), FRETTING, FRETTING CORROSION, METAL SURFACES, SOLID...
The problem of fretting in aircraft turbine engines is discussed. Critical fretting can occur on fan, compressor, and turbine blade mountings, as well as on splines, rolling element bearing races, and secondary sealing elements of face type seals. Structural fatigue failures have been shown to occur at fretted areas on component parts. Methods used by designers to reduce the effects of fretting are given.
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT ENGINES, FATIGUE (MATERIALS), FRETTING, FRETTING...
557
557
May 27, 2011
05/11
by
Angelini, Lorella; Christian, Eric; Barthelmy, Scott; Palmer, David; Mitchell, John; Esposito, Joseph; Sreekumar, P.; Hua, Xin-Min; Mandzhavidze, Natalie; Chan, Kai-Wing; Soong, Yang; Corcoran, Michael; Barrett, Paul, et al; Drake, Stephen; McGlynn, Thomas A.; Snowden, Stephen; Mukai, Koji; Cannizzo, John; Lochner, James; Rots, Arnold
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This report reviews activities performed by the members of the USRA contract team during the 6 months of the reporting period and projected activities during the coming 6 months. Activities take place at the Goddard Space Flight Center, within the Laboratory for High Energy Astrophysics. Developments concern instrumentation, observation, data analysis, and theoretical work in astrophysics. Supported missions include advanced Satellite for Cosmology and Astrophysics (ASCA), X-Ray Timing...
Topics: FRETTING, NICKEL COATINGS, METAL SURFACES, ELECTROLESS DEPOSITION, STRESS DISTRIBUTION,...
Personnel in the Quality and Integrity Design Engineering Center (QIDEC) at the University of Utah are working under a two year grant from the FAA to better understand the role of fretting corrosion and fretting fatigue in aircraft rivet hole cracking. The current program follows a one year grant program which was completed in 1993. This paper provides a status report on the results of these grant programs. Recent effort has been focused on developing basic fretting fatigue models which...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT STRUCTURES, COEFFICIENT OF FRICTION, CRACK GEOMETRY,...
2
2.0
Dec 1, 2021
12/21
by
Kevin Swanson (rockpapst)
data
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Free to use! You will need a screw for tightening it on you Dremel!
Topics: fretting, tools, tang, 3D Printing, Lutherie, fretwire, thingiverse, guitar, Jig, frettang, stl,...
In the late 1990s, Lambda Research Inc., of Cincinnati, Ohio, received Small Business Innovation Research (SBIR) awards from Glenn Research Center to demonstrate low plasticity burnishing (LPB) on metal engine components. By producing a thermally stable deep layer of compressive residual stress, LPB significantly strengthened turbine alloys. After Lambda patented the process, the Federal Aviation Administration accepted LPB for repair and alteration of commercial aircraft components, the U.S....
Topics: NASA Technical Reports Server (NTRS), IMPLANTATION, THERMAL STABILITY, RESIDUAL STRESS, PLASTIC...
Experiments were conducted to study fretting of gears. The gears were made from case-carburized AISI 9310 alloy to match the material of a flight actuator gearbox of interest. The objective of the testing was to produce damage representative of that observed on flight hardware. The following correlations and observations were noted. The amplitude of dithering motion very strongly influenced the type and magnitude of damage. Sliding amounts on the order of 30% of the width of the line contact...
Topics: NASA Technical Reports Server (NTRS), FRETTING, TRANSMISSIONS (MACHINE ELEMENTS), SURFACE...
The fretting damage to each of two different surface finishes on each of two degrees of hardness of test specimens of the same carbon steel was determined. Five greases of nearly identical composition and physical characteristics were used, thus conceivably nullifying any effect due to these grease properties. If the hardness of the specimens was the same, the smoother finish suffered the most fretting damage in all but one case. When the effects of surface finish was considered it was observed...
Topics: DTIC Archive, Calhoun, S F, ROCK ISLAND ARSENAL IL, *CORROSION, *STEEL, *FRETTING, STRESSES,...
This is the 5th volume of a 6 part report on a program to develop the design criteria and analytical methods necessary to ensure the damage tolerance of aircraft attachment lugs. This program consisted of seven tasks proceeding from and extensive cracking data survey and assessment of nondestructive inspection capabilities (NDI), through analysis methods development and evaluation, to the recommending of the damage tolerance design criteria for aircraft attachment lugs. Volume I-IV provide:...
Topics: DTIC Archive, Kathiresan, K, LOCKHEED-GEORGIA CO MARIETTA, *AIRCRAFT, *DAMAGE, *AIRFRAMES, *LUGS,...
Fretting wear experiments with several pure metals were conducted in air at various relative humidity levels. The materials used were iron, aluminum, copper, silver, chromium, titanium, and nickel. Each pure metal had a maximum fretting wear volume at a specific humidity level RH sub max that was not dependent on mechanical factors such as contact load, fretting amplitude, and frequency in the ranges studied. The weight loss due to fretting wear at RH sub max for each pure metal decreased with...
Topics: NASA Technical Reports Server (NTRS), FRETTING, HUMIDITY, METALS, WEAR, ADSORPTION, AIR, OXYGEN,...
Topics: DTIC Archive, DAVIS, LAURENCE R, OKLAHOMA UNIV NORMAN, *CORROSION INHIBITION, *STEEL, *LUBRICANTS,...
A titanium - 6-percent-aluminum - 4-percent-vanadium alloy (Ti-6Al-4V) was subjected to fretting-wear exposures against uncoated Ti-6Al-4V as a baseline and against various coatings and surface treatments applied to Ti-6Al-4V. The coatings evaluated included plasma-sprayed tungsten carbide with 12 percent cobalt, aluminum oxide with 13 percent titanium oxide, chromium oxide, and aluminum bronze with 10 percent aromatic polyester; polymer-bonded polyimide, polyimide with graphite fluoride,...
Topics: NASA Technical Reports Server (NTRS), CORROSION RESISTANCE, FRETTING, PROTECTIVE COATINGS, TITANIUM...
This program was designed to allow interaction between MURI investigators and Southwest Research Institute and to allow SwRI to perform independent research on high cycle fatigue mechanisms. The program goals were met. Two students performed experiments with the SwRI micromechanics facilities. Four manuscripts for publication are included in this report from the independent research effort. The results show (1) that fretting fatigue in the blade-disk attachment is a very difficult damage...
Topics: DTIC Archive, Davidson, David L., SOUTHWEST RESEARCH INST SAN ANTONIO TX, *FATIGUE(MECHANICS),...
Contacting metal surfaces subjected to pressure and relative motion suffer from a phenomenon known as fretting corrosion. When one of the two surfaces is also subjected to cyclic stress this phenomenon can lead to premature fatigue crack initiation and is known as fretting fatigue. Important variables in this process are the magnitude of relative displacement, contact pressure, frequency, relative hardness of contacting surfaces, intrinsic fatigue resistance and possibly environment and...
Topics: DTIC Archive, Duquette,D J, RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF MATERIALS ENGINEERING,...
Superalloys containing chromium showed decreasing fretting damage with increasing temperature of 816 C. This trend was related to the ability of the alloys to generate self-protecting oxide films. The damage at 816 C was one-third to one-tenth of that at 23 C. Osmium, chromium, and chromium carbide platings were fretted at 23 and 450 C. Osmium was extremely protective at 23 C but oxidized excessively at 450 C. Chromium and chromium carbide gave about the same protection at 450 C as the oxide...
Topics: NASA Technical Reports Server (NTRS), CHROMIUM ALLOYS, HEAT RESISTANT ALLOYS, TEMPERATURE EFFECTS,...
The multitask objectives of the plan discussed in this proposal are to research the role and effects of fretting on structural life of components; develop and demonstrate the feasibility of integrating candidate fretting fatigue predictive analytic model(s) into structural integrity methods; integrate and implement the techniques for applications to present and future U.S. military weapons programs, commercial aviation, automotive, and mechanical equipment; and provide industry access to the...
Topics: DTIC Archive, Brooks, C L, APES INC ST LOUIS MO, *FATIGUE(MECHANICS), *STRUCTURAL COMPONENTS,...
This research in support of the Air Force Research Laboratory, Materials and Manufacturing Directorate was conducted at Wright-Patterson AFB, Ohio from 19 May 2003 through 30 November 2006. This task examined fretting wear that is an accumulation of damage that occurs at component interfaces that are subjected to high contact stresses coupled with low amplitude oscillation. In the titanium dovetail joints of turbine engines, fretting wear can be severe. Surface treatments, such as plasma...
Topics: DTIC Archive, UNIVERSAL TECHNOLOGY CORP DAYTON OH, *COATINGS, TURBINE BLADES, PROTECTIVE COATINGS,...
Various properties of metals and alloys were studied with respect to their effect on the initial stage of the fretting process, namely adhesion. Crystallographic orientation, crystal structure, interfacial binding energies of dissimiliar metal, segregation of alloy constituents and the nature and structure of surface films were found to influence adhesion. High atomic density, low surface energy grain orientations exhibited lower adhesion than other orientations. Knowledge of interfacial...
Topics: NASA Technical Reports Server (NTRS), ADHESION, FRETTING, SURFACE PROPERTIES, ADHESIVE BONDING,...
The fatigue behavior (stress-life curve) of gamma titanium aluminide (Ti-48Al-2Cr-2Nb, atomic percent) was examined by conducting two tests: first, a fretting wear test with a fatigue specimen in contact with a typical nickel-based superalloy contact pad in air at temperatures of 296 and 823 K and second, a high-cycle fatigue test of the prefretted Ti-48Al-2Cr-2Nb fatigue specimen at 923 K. Reference high-cycle fatigue tests were also conducted with unfretted Ti-48Al-2Cr-2Nb specimens at 923 K....
Topics: NASA Technical Reports Server (NTRS), FATIGUE TESTS, FRETTING, POROSITY, TITANIUM ALUMINIDES, WEAR...
Part of the redesign of the SRMs for the Space Shuttle involved the substitution of three new capture cylinders for three of the previously used cylinders. These new cylinders mate with the old standard case segments in each of the three field joints. The new capture cylinders contain an integral capture latch on the tang end which mates with a case clevis during stackup at KSC. The capture cylinders also contain a groove in the capture latch to provide for a third 0-ring in the joint and are...
Topics: NASA Technical Reports Server (NTRS), FRETTING, NICKEL COATINGS, METAL SURFACES, ELECTROLESS...
Fretting wear experiments were conducted on high-purity titanium at temperatures up to 650 C. Results indicate that up to about 500 C, the fretting wear increases with temperature. A further increase in the temperature up to 650 C results in decreasing fretting wear. This change in trend of fretting wear with temperature is shown to be associated with a change in oxidation rate. Additional experiments at 650 C showed a transmission from a low rate of fretting wear to a higher rate occurred...
Topics: NASA Technical Reports Server (NTRS), AIR, FRETTING, HIGH TEMPERATURE TESTS, TITANIUM, OXIDATION,...
No abstract available
Topics: NASA Technical Reports Server (NTRS), PROTECTIVE COATINGS, LININGS, DURABILITY, CERAMIC MATRIX...
The present paper is concerned with the application of a "plasticity-induced" crack closure model to study fatigue crack growth under various load histories. The model was based on the Dugdale model but modified to leave plastically deformed material in the wake of the advancing crack. The model was used to correlate crack growth rates under constant-amplitude loading and then used to predict crack growth under variable-amplitude and spectrum loading on thin-sheet 2024- T3 aluminum...
Topics: NASA Technical Reports Server (NTRS), CRACK PROPAGATION, FATIGUE (MATERIALS), ALUMINUM ALLOYS,...
Fretting wear experiments were conducted on high purity iron, nickel and titanium in air under conditions of varied humidity and temperature, and in nitrogen. For iron and titanium, maximum fretting occurred at 10 and 30 percent relative humidity respectively. Nickel showed a minimum in fretting wear at about 10 percent relative humidity. With increasing temperature, all three metals initially showed reduced fretting wear, with increasing wear observed as temperatures increased beyond 200-300...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC MOISTURE, ATMOSPHERIC TEMPERATURE, FRETTING...
Additional support is presented for the previously proposed role of hydrogen as an embrittling agent in hot-salt stress corrosion cracking of titanium-aluminum alloys. The main source of hydrogen formed during the reactions of titanium alloys with hot salt was identified as water associated with the salt. Hydrogen is produced by the reaction of an intermediate (hydrogen halide) with the alloy rather than from metal-water reactions. The fracture mode of precracked tensile specimens was ductile...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, EMBRITTLEMENT, HYDROGEN, SALT BATHS, STRESS...
Fretting fatigue crack nucleation behavior in titanium alloy Ti-6A1-4V was investigated by using two contact configurations: cylinder or flat with rounded edge pad on flat substrate. Both experiments and finite element analyses were conducted. A muiltiaxial fatigue parameter involving shear stress and normal stress on the critical plane was examined about its capability to predict the number of cycles to fretting fatigue crack initiation, crack initiation location and crack orientation angle...
Topics: DTIC Archive, Mall, S., AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH, *CRACKS, *TITANIUM ALLOYS,...
Friction dampers are required to reduce the magnitude of vibrational stresses in high-aspect-ratio blading of compressors for advanced aircraft turbine engines. Fret ting Is a common problem with all types of friction dampers. Fretting experiments with simulated wire-lace blade damping were conducted with Inconel 600. Experiments were run with or without oxide coatings In contact with maraging steel. Although two methods were used to form the oxide, high friction and low wear occurred with...
Topics: DTIC Archive, Swikert, Max A, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS...
Ti-6Al-4V specimens subjected to fretting fatigue at 400 C have been examined in SEM. Layer formation similar to that obtained on specimens tested at 200 and 600 C was observed. Fatigue and fretting fatigue curves have been determined on Inconel 718 at 20, 280, and 540 C, together with isolated observations at 700 C where creep becomes excessive. Raising the temperature has little effect on fatigue strength but improves the fretting fatigue strength. The improvement is thought to be due to...
Topics: DTIC Archive, Waterhouse,R B, NOTTINGHAM UNIV (ENGLAND) DEPT OF METALLURGY, *FATIGUE(MECHANICS),...
Fretting fatigue experiments conducted on 304 stainless steel using a flexural-fatigue test arrangement with bolted-on fretting pads have demonstrated that fatigue life is reduced by at least a factor of 10 in the 265- to 334-MPa (38,500- to 48,500-psi) nominal-flexural-fatigue-stress range. In addition, experiments in which the fretting pads were removed after selected numbers of cycles, followed by continued flexural fatigue without fretting show that continued fretting beyond 50,000 cycles...
Topics: DTIC Archive, Bill, Robert C., NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS...
A fatigue analysis, based on finite-element calculations and fatigue tests, was conducted for an aluminum-alloy sheet specimen with a steel interference-fit bolt. The stress analysis of the region near the bolt hole showed that the beneficial effect of an interference-fit bolt can be interpreted as the combined result of two effects: (1) load transfer through the bolt and (2) the compressive interference stresses in the sheet. Results of the fatigue tests show that progressively higher...
Topics: NASA Technical Reports Server (NTRS), BOLTS, FATIGUE TESTS, INTERFERENCE, INTERFERENCE FIT, METAL...
This program was a follow-on effort to a program on Improved High Cycle Fatigue (HCF) Life Prediction, USAF Contract F33615-96-C-5269, the results of which are documented in the final report on that PRDA program 1. This program continued work on addressing key issues associated with developing, verifying, & implementing a material damage tolerant design methodology capable of predicting HCF limits & material thresholds for Ti-6Al-4V. The methodology development was extended to another...
Topics: DTIC Archive, Gallagher, J, DAYTON UNIV OH RESEARCH INST, *FATIGUE(MECHANICS), SINGLE CRYSTALS,...
Damage and plastic deformation accumulation in fretting fatigue occurs within a depth of a few crystallographic grains. Therefore, more accurate assumptions concerning length scale, damage volume, and the material model are needed to establish a more solid physical foundation necessary for next generation fretting fatigue damage prediction. Major thrusts include: (1) development and implementation of a 3-D crystal viscoplasticity model for Ti-6A1-4V. (2) realistic 3-D fretting simulations that...
Topics: DTIC Archive, GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS SCIENCE AND ENGINEERING,...
A unique dovetail fretting fatigue fixture was designed and evaluated for testing turbine engine materials at room or elevated temperatures. Materials from the cold section and hot sections of military turbojet engines were chosen for testing. The new fixture was improved over the previously used dovetail fretting fatigue fixture by including direct measurement of contact forces, alignment control, and elevated temperature capability. Measurement of the shear component of the contact force was...
Topics: DTIC Archive, Golden, Patrick J, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND...
A preliminary metallurgical investigation of the damaged, Ti-3A1-2.5V, V-22 System 1 Pump Suction Tube of the V-22 Osprey aircraft, identified as 901-081-904-101, has been completed. The 1.0 inch (2.54 cm) diameter tube sustained localized damage where it was secured by a rubber clamp to the transmission. That portion of the tube was excised, sectioned, and examined using metallography and a Scanning Electron Microscope (S EM). Qualitative chemical analysis utilizing Energy Dispersive...
Topics: DTIC Archive, Agarwala, V. V., NAVMAR INC WARMINSTER PA, *HYDRAULIC EQUIPMENT, *TITANIUM ALLOYS,...
The performance of the 360L009, Ninth Flight, Redesigned Solid Rocket Motors (RSRM) is assessed in respect to case hardware and joint sealing issues as seen from post-fire assessment of the case and seals. In addition, all of the potential anomalies have been classified and summarized. The post-fire assessment of both motors showed the case segments to be in good condition. Field joint fretting of this flight set ranged from light on most of the joints to locally heavy on three of the joints....
Topics: NASA Technical Reports Server (NTRS), DAMAGE, FRETTING, JOINTS (JUNCTIONS), ROCKET ENGINE CASES,...
A series of four nickel-based alloys containing 10 percent and 20 percent chromium in combination with 2 percent and 5 percent aluminum were fretted in dry air at temperatures to 816 C. At all temperatures, the alloys showed far less fretting wear than did high-purity nickel. This was attributed to the formation of protective oxide films on the alloys, the result of the selective oxidation of the alloy constituents. Increasing the aluminum concentration reduced fretting wear at all...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, CHROMIUM ALLOYS, FRETTING, HIGH TEMPERATURE...
Fretting experiments were conducted on titanium, a series of Ni-Cr-Al alloys and on some high temperature turbine alloys at room temperature and at elevated temperatures in air and in various inert environments. It was found that, depending on temperature and environment, the fretting behavior of the materials examined could be classified according to four general types of behavior. Briefly, these types of behavior were: (1) the complete absence of oxidation, as in inert environments, generally...
Topics: NASA Technical Reports Server (NTRS), EROSION, FRETTING, MATHEMATICAL MODELS, OXIDATION, REFRACTORY...
This research in support of the Air Force Research Laboratory Materials and Manufacturing Directorate was conducted at Wright-Patterson AFB, Ohio from 14 November 2006 through 1 February 2008. This task worked to develop and test anti-fretting coating systems for application to Al and Ti alloys able to withstand high cyclic loadings in contact with steel counterparts. Fretting wear is an accumulation of damage that occurs at component interfaces that are subjected to high contact stresses...
Topics: DTIC Archive, UNIVERSAL TECHNOLOGY CORP DAYTON OH, *PROTECTIVE COATINGS, *FRETTING, ADHESION,...
Composite feedlines with metal liners have the potential to reduce weight/cost while providing the same level of permeation resistance and material compatibility of all-metal feedlines carrying cryogenic propellants in spacecraft. The major technical challenges are the large difference in Coefficient of Thermal Expansion between the liner and the composite, and the manufacturing method required to make a very thin liner with the required strength and dimensional tolerance. This study...
Topics: NASA Technical Reports Server (NTRS), CRYOGENICS, FEED SYSTEMS, LININGS, PIPES (TUBES), THERMAL...
Surface enhancement technologies such as shot peening (SP), laser shock peening (LSP), and low plasticity burnishing (LPB) can provide substantial fatigue life improvement. However, to be effective, the compressive residual stresses that increase fatigue strength must be retained in service. LPB provides thermally stable compression and can be performed in conventional machine shop environments on CNC machine tools. LPB enables the extension of component service lives fatigue limited by various...
Topics: DTIC Archive, Prevey, Paul S, LAMBDA RESEARCH CINCINNATI OH, *FATIGUE LIFE, *PLASTIC PROPERTIES,...
Wide temperature, solid lubricant films offer payoffs for military turbomachinery components: rub seals, face seals, fretting interfaces and bearings. Multilayer films of B4C/Mo, B4C/Cr, Zn/W, Ni/Ti, Au/Cr, W/MoS and AlCuFeCr films were deposited by planar magnetron sputtering or ion bombardment assisted deposition (IBAD), and evaluated for adhesion, friction and wear properties from room temperature to as high as 1100 deg F. Oxidized Zn/W and W/MoS2 films exhibited low friction coefficients at...
Topics: DTIC Archive, Fehrenbacher, Larry L., TECHNOLOGY ASSESSMENT AND TRANSFER INC ANNAPOLIS MD,...
Experimental evaluation under simulated engine conditions revealed that conventional mainshaft seals have disadvantages of high gas leakage rates and wear. An advanced seal concept, the self-acting face seal, has a much lower gas leakage rate and greater pressure and speed capability. In endurance tests (150 hr) to 43 200 rpm the self-acting seal wear was not measurable, indicating noncontact sealing operation was maintained even at this high rotative speed. A review of published data revealed...
Topics: NASA Technical Reports Server (NTRS), FRETTING, GAS FLOW, GAS TURBINE ENGINES, LEAKAGE, PACKINGS...
Damage scar volume measurements taken from like metal fretting pairs combined with scanning electron microscopy observations showed that three sequentially operating mechanisms result in the fretting of titanium, Monel-400, and cobalt - 25-percent molybdenum. Initially, adhesion and plastic deformation of the surface played an important role. This was followed after a few hundred cycles by a fatigue mechanism which produced spall-like pits in the damage scar. Finally, a combination of oxidation...
Topics: NASA Technical Reports Server (NTRS), ELECTRON MICROSCOPES, FRETTING CORROSION, METAL FATIGUE,...
The objectives of the work reported were to define potentially useful failure prediction models for the wear and fretting-wear modes of failure, to define the parameters of primary importance, to incorporate the concept of accelerated testing both in the prediction models and in the design of a testing program, and to design special testing machines capable of both real-time and accelerated-wear and fretting-wear tests using a UH-1H helicopter cyclic servo support bearing as the test specimen....
Topics: DTIC Archive, Collins, Jack A, OHIO STATE UNIV COLUMBUS DEPT OF MECHANICAL AND AEROSPACE...
