Download or read book Surface fatigue evaluation of gear materials and lubricants Physics and Process Modeling PPM and Other Propulsion R and T Volume 2 written by Dennis P. Townsend and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Materials Research for Lubricants and Heat Transfer Fluids written by Karl R. Mecklenburg and published by . This book was released on 1961 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Correlation of Specific Film Thickness and Gear Pitting Life written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-13 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness defined as the ratio of lubricant film thickness to the composite surface roughness. It can be difficult to combine results of studies to create a cohesive and comprehensive dataset. In this work gear surface fatigue lives for a wide range of specific film values were studied using tests done with common rigs, speeds, lubricant temperatures, and test procedures. This study includes previously reported data, results of an additional 50 tests, and detailed information from lab notes and tested gears. The dataset comprised 258 tests covering specific film values (0.47 to 5.2). The experimentally determined surface fatigue lives, quantified as 10-percent life estimates, ranged from 8.7 to 86.8 million cycles. The trend is one of increasing life for increasing specific film. The trend is nonlinear. The observed trends were found to be in good agreement with data and recommended practice for gears and bearings. The results obtained will perhaps allow for the specific film parameter to be used with more confidence and precision to assess gear surface fatigue for purpose of design, rating, and technology development. Krantz, Timothy L. Glenn Research Center WBS 380046.02.03.02.02.01

Download or read book Surface Fatigue Lives of Case Carburized Gears With an Improved Surface Finish written by and published by . This book was released on 2000 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 9310 steel gears was provided with a near-mirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were determined using data from metrology, profilometry, and interferometric microscope inspections. The superfinishing reduced the roughness average by about a factor of 5. The superfinished gears were subjected to surface fatigue testing at 1.71-GPa (248-ksi) Hertz contact stress, and the data were compared with the NASA Glenn gear fatigue data base. The lives of gears with superfinished teeth were about four times greater compared with the lives of gears with ground teeth but with otherwise similar quality.

Download or read book The Influence of Roughness on Gear Surface Fatigue written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gear working surfaces are subjected to repeated rolling and sliding contacts, and often designs require loads sufficient to cause eventual fatigue of the surface. This research provides experimental data and analytical tools to further the understanding of the causal relationship of gear surface roughness to surface fatigue. The research included evaluations and developments of statistical tools for gear fatigue data, experimental evaluation of the surface fatigue lives of superfinished gears with a near-mirror quality, and evaluations of the experiments by analytical methods and surface inspections. Alternative statistical methods were evaluated using Monte Carlo studies leading to a final recommendation to describe gear fatigue data using a Weibull distribution, maximum likelihood estimates of shape and scale parameters, and a presumed zero-valued location parameter. A new method was developed for comparing two datasets by extending the current methods of likelihood-ratio based statistics. The surface fatigue lives of superfinished gears were evaluated by carefully controlled experiments, and it is shown conclusively that superfinishing of gears can provide for significantly greater lives relative to ground gears. The measured life improvement was approximately a factor of five. To assist with application of this finding to products, the experimental condition was evaluated. The fatigue life results were expressed in terms of specific film thickness and shown to be consistent with bearing data. Elastohydrodynamic and stress analyses were completed to relate the stress condition to fatigue. Smooth-surface models do not adequately explain the improved fatigue lives. Based on analyses using a rough surface model, it is concluded that the improved fatigue lives of superfinished gears is due to a reduced rate of near-surface micropitting fatigue processes, not due to any reduced rate of spalling (sub-surface) fatigue processes. To complete the evaluations, surface insp

Download or read book Finite Element Based Surface Fatigue Estimation in Involute Spur Gear written by Solomon Tekeste and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pitting and scoring is a phenomenon in which small particles are removed from the surface of the tooth due to the high contact stresses that are present between mating teeth. After the investigation of shot pinning to increase the tooth bending strength in gears, surface durability, in the form of macro and micro-pitting, is now considered the dominant restriction on gear life and performance. In this book a method is develop to study surface fatigue in involute spur gears using finite element analysis. In achieving this two-dimensional & three-dimensional equivalent contacting cylinders & three-dimensional model of involute spur gear is used. The modeling is done using finite element computer package, ANSYS & solid modeling software, CATIA. In this book effect of loading condition and material types in contact stress in gears, estimation of surface fatigue in rolling-sliding contact condition in spur gear, effect of initial surface roughness on surface fatigue is studied. The results obtained are compared with analytical method.

Download or read book Laboratory Performance Tests for Automotive Gear Lubricants Intended for API GL 5 Service written by and published by ASTM International. This book was released on 1987 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Systematic Analysis of Gear Failures written by Lester E. Alban and published by ASM International. This book was released on 1985-01-01 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the detailed steps necessary to determine the causes of failure. First, the physical characteristics of a gear are studied: where the stress points are, from what directions the forces are applied, where the movement of material progresses, and where strain patterns exist. Second, all external conditions and forces are considered. With this background information, a systematic examination is described from beginning to end, the end being a conclusion about the mode and cause of failure.

Download or read book Fatigue Data Handbook written by A. Buch and published by Trans Tech Publications Ltd. This book was released on 1998-03-17 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: This authoritative handbook presents an extensive compilation of data covering all important fatigue situations - fatigue strength of steels and other materials, notch- , size-, and mean stress effects, influence of temperature and corrosion, influence of special surface treatments, fatigue of structural elements and welds, aircraft fatigue, multilevel loading test programs, fatigue performance prediction etc.As is well known, fatigue investigations are often extremely time-consuming. The results of the tests depend upon numerous factors, and therefore handbook data must include all of the parameters which affect reported test results. The calculation of fatigue life and strength cannot be performed without having appropriate information concerning the specific fatigue situation. Nor can test programs be properly prepared without knowing the service conditions and the results of previous tests as, otherwise, the results obtained cannot be generalized. Information on component fatigue behaviour is of importance not only to machine designers but also to production engineers in charge of component manufacture, since processing strongly affects fatigue strength, and to maintenance engineers in charge of the operation and repair of cyclically loaded machine elements.

Download or read book Surface Fatigue Life of High Temperature Gear Materials written by and published by . This book was released on 1994 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three high temperature gear materials were evaluated using spur gear surface fatigue tests. These materials were, VASCO max 350, VASCO matrix H, and nitralloy N and were evaluated for possible use in high temperature gear applications. The fatigue life of the three high temperature gear materials were compared with the life of the standard AISI 9310 aircraft gear material. Surface fatigue tests were conducted at a lubricant inlet temperature of 321 K (120 deg F), a lubricant outlet temperature of 350 K (170 deg F), a maximum Hertz stress of 1.71 GPa (248 ksi), a speed of 10000 rpm and with a synthetic paraffinic lubricant. The life of the nitralloy N was approximately the same as the MSI 9310, the life of the VASCO max 350 was much less than the AISI 9310 while the life of the VASCO matrix H was several times the life of the AISI 9310. The VASCO max 350 also showed very low fracture toughness with approximately half of the gears failed by tooth fracture through the fatigue spall. The VASCO matrix II had approximately 10-percent fracture failure through the fatigue spalls indicating moderate to good fracture toughness. (MM).

Download or read book Evaluation of Advanced Lubricants for Aircraft Applications Using Gear Surface Fatigue Tests written by and published by . This book was released on 1991 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface pitting fatigue life tests were conducted with five lubricants, using spur gears made from a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 steel. The gears were case carburized and hardened to a Rockwell C-60 and finish ground. The gear pitch diameter was 8.89 cm (3.5 in.). The lot of gears was divided into five groups, each of which was tested with a different lubricant. The test lubricants can be classified as synthetic polyol-esters with various viscosities and additive packages. Test conditions included a bulk gear temperature of 350 K (170 F), a maximum Hertz stress of 1. 71 GPa (248 ksi) at the pitch line, and a speed of 10,000 RPM. The following results were obtained. The lubricant with a viscosity that provided a specific film thickness greater than one and with an additive package produced far greater surface fatigue lives than lubricants with a viscosity that provided specific film thickness less than one. A low viscosity lubricant with an additive package produced gear surface fatigue lives equivalent to a similar base stock lubricant with 30 percent higher viscosity but without an additive package. Lubricants with the same viscosity and similar additive packages gave equivalent gear surface fatigue lives.

Download or read book An Experimental Investigation of the Influence of the Lubricant Viscosity and Additives on Gear Wear written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-24 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of lubricant viscosity and additives on the average wear rate of spur gear pairs was investigated experimentally. The gear specimens of a comprehensive gear durability test program that made use of seven lubricants covering a range of viscosities were examined to measure gear tooth wear. The measured wear was related to the as-manufactured surface roughness, the elastohydrodynamic film thickness, and the experimentally determined contact fatigue lives of the same specimens. In general, the wear rate was found to be inversely proportional to the viscosity of the lubricant and to the lambda ratio (also sometimes called the specific film thickness). The data also show an exponential trend between the average wear rates and the surface fatigue lives. Lubricants with similar viscosities but differing additives and compositions had somewhat differing gear surface fatigue lives and wear rates. Krantz, Timothy L. and Kahraman, Ahmet Glenn Research Center NASA/TM-2005-213956, ARL-TR-3126, E-15272

Download or read book Laboratory Performance Tests for Automotive Gear Lubricants Intended for API GL 4 GL 5 and GL 6 Services written by ASTM Committee D-2 Staff and published by . This book was released on 1972-01-01 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermomechanical Fatigue Behavior of Materials written by Michael A. McGaw and published by ASTM International. This book was released on 2003 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: "ASTM Stock Number: STP1428. - "Fourth Symposium on Thermomechanical Fatigue Behavior of Materials, held in Dallas, Texas on November 7-8, 2001. The Symposium was sponsored by ASTM Committee E08 on Fatigue and Fracture and its Subcommittee E08.05 on Cyclic Deformation and Fat. - Includes bibliographical references and indexes. ASTM International; 2011.

Download or read book Lubricant Metallurgy Interaction Effects on Turbine Engine Lubricant Load Rating written by P. M. Ku and published by . This book was released on 1976 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: This investigation has as its objective the development of an improved methodology for aircraft power spur gear design, with primary emphasis on gear-tooth scuffing (scoring) and secondary emphasis on gear-tooth pitting (surface fatigue). Toward this end, mathematical models are proposed for scuffing and pitting, as well as for another relevant but less important failure mode, rubbing wear. Basic data for the scuffing and pitting models were derived from sliding-rolling disk tests using the AFAPL disk tester. Gear scuffing and pitting tests were also performed, using two WADD gear machines, to evaluate the validity of the two models. The scuffing model was found to yield scuff-limited gear power-transmitting capacities to about five percent of the actual. However, the several correlating factors employed in the model require independent confirmation and rationalization. The pitting model was found to yield gear pitting lives about ten times the actual, due principally to the weak statistical base of the quantitative data available and also a lack of basic understanding of the pitting process in gears. The wear model, which is not within the scope of this investigation, was not tested. The investigation has revealed many areas where basic understanding or quantitative data are still inadequate. Recommendations for additional research are presented. (Author).

Download or read book Approaches to Modeling of Friction and Wear written by Frederick F. Ling and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the conclusion of the Conference on Tribology in the area of Wear Life Pre diction of Mechanical Components, which was held at the General Motors Research Laboratories and sponsored by the Industrial Research Institute, a very high pri ority recommendation was modeling of tribological systems. Since the appearance of the Conference Proceedings in 1985, the writers discussed the matter of modeling with Dr. Edward A. Saibel, Chief of the Solid Mechanics Branch, Engineering Sciences Division, U.S. Army Research Office. This discussion led to a proposal for the Workshop which resulted in this volume. The choice of proposal and Workshop name turned out to be more restricted than it needed to be. As such, the Workshop adopted the name for this volume, Approaches to Modeling of Friction and Wear. By design, the attendance was restricted to not more than 40 individuals so as to allow small group discussions. There were four panels which deliberated on the same questions after two invited area lectures. Section 1 contains the substance of the two lectures. Section 2 is the Workshop Summary which is a distillation of the four panel reports by the entire Workshop attendance. This was formally written up and edited by the eight panel session chairmen, i.e., each of the four panels met twice on two different questions under the leadership of a chairman for each session. Section 3 contains four brief position papers on the subject of the Workshop.

Download or read book Lubricants and Lubrication 2 Volume Set written by Theo Mang and published by John Wiley & Sons. This book was released on 2017-05-08 with total page 1220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Praise for the previous edition: "Contains something for everyone involved in lubricant technology." —Chemistry & Industry This completely revised third edition incorporates the latest data available and reflects the knowledge of one of the largest companies active in the business. The authors take into account the interdisciplinary character of the field, considering aspects of engineering, materials science, chemistry, health and safety. The result is a volume providing chemists and engineers with a clear interdisciplinary introduction and guide to all major lubricant applications, focusing not only on the various products but also on specific application engineering criteria. A classic reference work, completely revised and updated (approximately 35% new material) focusing on sustainability and the latest developments, technologies and processes of this multi billion dollar business Provides chemists and engineers with a clear interdisciplinary introduction and guide to all major lubricant applications, looking not only at the various products but also at specific application engineering criteria All chapters are updated in terms of environmental and operational safety. New guidelines, such as REACH, recycling alternatives and biodegradable base oils are introduced Discusses the integration of micro- and nano-tribology and lubrication systems Reflects the knowledge of Fuchs Petrolub SE, one of the largest companies active in the lubrication business 2 Volumes wileyonlinelibrary.com/ref/lubricants