Download or read book An Experimental Study of the Impact of Various Tooth Surface Treatments on Spur Gear Pitting Life written by Jeremy Micah Bluestein and published by . This book was released on 2007 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In this study, the influence of various engineered surface treatments on the contact fatigue behavior of spur gear pairs was investigated, focusing on pitting life. A number of standard gear durability test machines were furbished and sets of specially designed spur gear test specimens were procured to execute a test matrix that includes gears having various surface treatments. Typical hobbed-shaved surfaces were considered to represent the baseline surface treatment and their pitting lives were compared to lives of gears having (i) chemically polished, (ii) shot-peened and plastic honed, and (iii) chemically polished and CrN coated surfaces. Pitting life of each variation was quantified at several stress levels by using a set of predetermined failure criteria, and test and inspection procedures. The data for each variation was processed statistically and compared to data from other surface variations. The results indicate that chemically polishing increases the pitting life of spur gears nearly three times over the life of the baseline hobbed-shaved gears. It was also observed that the shot-peened and plastic honed gears did not deliver any tangible pitting life improvements over the baseline conditions. Finally, a slight increase in pitting life was observed over chemically polished gears with the application of the CrN coating.
Download or read book An Investigation of the Influence of Micropitting on the Progression of Gear Surface Pitting written by Eunsung Kim and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the progression of micropitting and its effect on the fatigue life of a spur gear is investigated through an experimental study. Standard contact durability testing is performed on two test gears and an inspection is done throughout the gear's life cycle. Operating conditions for the test are closely controlled to minimize the effect of applied load, lubrication conditions, shaft rotation speed, and temperature on the micropitting behavior. Gear tooth topography is captured using a gear specific CMM and roughness measurement is obtained using a profilometer. Macroscopic images are also taken to have a record of the physical appearance of the gear flank. Using the experimental data, the severity of surface degradation due to micropitting is quantified by measuring the maximum profile deviation from the initial state. Gear tooth surface topography is used in a load distribution prediction. The change in contact stress distribution and maximum contact stress location are compared to the gear tooth surface topography over the life of the gear to study the effect of micropitting. Contact stress data is then applied to a multi-axial fatigue damage model using the critical plane approach to calculate the fatigue damage parameter. The critical plane is determined by testing which candidate plane produces the maximum shear strain amplitude. Stress and strain components on this critical plane are then applied to the fatigue damage model to calculate the predicted number of cycles to failure, and a damage accumulation rule is employed to predict crack initiation. The maximum accumulated damage location closely aligned with the maximum contact stress location as well as the maximum critical-plane shear strain location. Most importantly, these locations corresponded to the pitting location. Based on the experimental and modelled results, micropitting significantly influences the contact stress distribution that leads to stress concentration, potentially leading to contact fatigue failure such as pitting. The fatigue damage prediction model is somewhat validated through the minimal experimental data further experimental data is needed to develop a method of predicting pitting initiation accurately.
Download or read book Predicted Effect of Dynamic Load on Pitting Fatigue Life for Low contact ratio Spur Gears written by David G. Lewicki and published by . This book was released on 1986 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: How dynamic load affects the surface pitting fatigue life of external spur gears was predicted by using NASA computer program TELSGE. Parametric studies were performed over a range of various gear parameters modeling low-contact-ratio involute spur gears. In general, gear life predictions based on dynamic loads differed significantly from those based on static loads, with the predictions being strongly influenced by the maximum dynamic load during contact. Gear mesh operating speed strongly affected predicted dynamic load and life. Meshes operating at a resonant speed or one-half the resonant speed had significantly shorter lives. Dynamic life factors for gear surface pitting fatigue were developed on the basis of the parametric studies. In general, meshes with higher contact ratios had higher dynamic life factors than meshes with lower contact ratios. A design chart was developed for hand calculations of dynamic life factors. (Author).
Download or read book A Comparative Study of the Impact of Dip and Jet Lubrication Methods on Spur Gear Contact Fatigue and Efficiency written by Jeremy C. Moss and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of spur gear efficiency is conducted under various jet-lubricated and dip-lubricated conditions. A test methodology is developed to measure load-independent (spin) and load-dependent (mechanical) losses to a gearbox containing a single spur gear pair. An experimental test matrix is defined to study the influence that the lubrication method has on these losses. The test matrix includes two dip-lubricated conditions that vary in submersion level of the gear pair, and four jet-lubricated conditions that vary in the gear mesh target location and velocity of the oil. Results indicate that the spin power losses are impacted by the lubrication method significantly while the mechanical losses are not influenced. An investigation of spur gear contact fatigue is conducted under several lubrication schemes from the efficiency study. A test methodology is developed to evaluate variations in tooth geometry due to surface wear, roughness, and pitting life. Pitting lives under each lubrication method are analyzed statistically to quantify any meaningful differences in gear pitting life. Results indicate that contact fatigue lives from jet-lubricated tests are as high as dip-lubricated ones as long as jet velocities are sufficient.
Download or read book An Experimental Investigation of the Impact of Engineered Surface Processes on Efficiency of Spur Gears written by Kreteeka Chaudhury and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was conducted to evaluate the effect of surface finish on spur gear power losses under jet lubrication. Four different surface finish combinations were tested: (i) hard ground surface pair, (ii) chemically polished surface pair, (iii) super honed surface pair and (iv) hard ground against chemically polished surface pair. The test was conducted at 432 different operating condition combinations of speed, torque, lubricant type and inlet temperature. An FZG back-to-back set up was used to conduct the test. Surface roughness inspections were carried out at regular intervals to monitor any changes in surface roughness characteristics. The measured power losses were resolved into spin (load independent) and mechanical (load dependent) power losses. The relation between both losses and various operating conditions were explored. As expected, spin power loss did not vary with variation in surface finish. Mechanical power loss increased with increase in speed and torque. Various surface roughness and operating parameters such as BAC curves and lambda ratio were calculated for each surface finish combination to study their correlation to power losses measured. For smoother surfaces, an increase in temperature decreased power loss as the viscosity of the lubricant decreased and hence rolling friction losses dominating the mechanical power loss decreased. However, for rougher surfaces sliding friction losses seemed to be dominant due to high amounts of asperity contact. Thus, more cases of higher power loss at high temperatures were observed for rougher surfaces.
Download or read book NASA Technical Paper written by and published by . This book was released on 1985 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Advances in Condition Monitoring and Structural Health Monitoring written by Len Gelman and published by Springer Nature. This book was released on 2021-02-02 with total page 759 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the selected contributions from the 2nd World Congress on Condition Monitoring (WCCM 2019), held in Singapore in December 2019. The contents focus on digitalisation for condition monitoring with the emergence of the fourth industrial revolution (Industry 4.0) and the Industrial Internet-of-Things (IIoT). The book covers latest research findings in the areas of condition monitoring, structural health monitoring, and non-destructive testing which are relevant for many sectors including aerospace, automotive, civil, oil and gas, marine, and manufacturing industries. Different monitoring systems and non-destructive testing methods are discussed to avoid failures, increase lifespans, and reduce maintenance costs of equipment and machinery. The broad scope of the contents will make this book interesting for academics and professionals working in the areas of non-destructive evaluation and condition monitoring.
Download or read book Tribology and Surface Engineering written by Aleksander Lisiecki and published by MDPI. This book was released on 2020-01-15 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book covers very important issues, not only scientific in nature but, ultimately, for industry and the economy. Wear and deterioration of surface properties during operation is a natural and unavoidable phenomenon. However, minimizing the degree of wear is of great importance for the entire economy, as illustrated by the example of the US economy, for which the loss of natural resources as a direct cause of friction and wear exceeds 6% of the Gross National Product. This book showcases the valuable knowledge revealed from both theoretical and practical research results in the field of advanced technologies of coatings and surface modification, as well as wear and tribological characteristics of advanced materials and surface layers. Therefore, it is hoped that this book will be a valuable resource and helpful tool for scientists, engineers, and students in the field of surface engineering, materials science, and manufacturing engineering.
Download or read book A Study on the Long Cycle Micro pitting Behavior of Spur Gear Pairs written by Suhas Ashok Kedilaya and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Contact fatigue behavior of a gear pair is typically gauged by size of macro-pits formed during the operation of the gear pair. It is common that very small pits form in certain tooth contact locations first. Macro-pits typically initiate from the boundaries of these micro-pitted zones. As most macro-pitting evaluations were performed at high- stress, medium-life conditions, micro-pit formation has often been overlooked. In this study, a set of spur gear experiments are performed under typical automotive speed, temperature and operating conditions with a modest torque transmitted, to investigate micro-pitting performance during ultra-long cycle operation up to 400 million cycles. Evolution of contact surfaces throughout each test are documented through interim inspections, including surface geometries, roughnesses and micro-pitted area. Digital imaging techniques are employed to automate the quantification of micro-pitted regions for each tooth image. The micro-pitting experiments are simulated by using an existing spur gear micro-pit life prediction methodology. Based on comparisons between predictions and measurements, an assessment on the accuracy and effectiveness of this methodology is made along with the potential areas of improvement.
Download or read book Interfacial Mechanics written by Jane Wang and published by CRC Press. This book was released on 2019-12-06 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the characteristics of material contact and lubrication at tribological interfaces is of great importance to engineering researchers and machine designers. Traditionally, contact and lubrication are separately studied due to technical difficulties, although they often coexist in reality and they are actually on the same physical ground. Fast research advancements in recent years have enabled the development and application of unified models and numerical approaches to simulate contact and lubrication, merging their studies into the domain of Interfacial Mechanics. This book provides updated information based on recent research progresses in related areas, which includes new concepts, theories, methods, and results for contact and lubrication problems involving elastic or inelastic materials, homogeneous or inhomogeneous contacting bodies, using stochastic or deterministic models for dealing with rough surfaces. It also contains unified models and numerical methods for mixed lubrication studies, analyses of interfacial frictional and thermal behaviors, as well as theories for studying the effects of multiple fields on interfacial characteristics. The book intends to reflect the recent trends of research by focusing on numerical simulation and problem solving techniques for practical interfaces of engineered surfaces and materials. This book is written primarily for graduate and senior undergraduate students, engineers, and researchers in the fields of tribology, lubrication, surface engineering, materials science and engineering, and mechanical engineering.
Download or read book NASA Reference Publication written by and published by . This book was released on 1977 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Paper written by and published by . This book was released on 1985 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Condition Monitoring and Structural Health Monitoring written by Len Gelman and published by Springer. This book was released on 2021-02-03 with total page 795 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the selected contributions from the 2nd World Congress on Condition Monitoring (WCCM 2019), held in Singapore in December 2019. The contents focus on digitalisation for condition monitoring with the emergence of the fourth industrial revolution (Industry 4.0) and the Industrial Internet-of-Things (IIoT). The book covers latest research findings in the areas of condition monitoring, structural health monitoring, and non-destructive testing which are relevant for many sectors including aerospace, automotive, civil, oil and gas, marine, and manufacturing industries. Different monitoring systems and non-destructive testing methods are discussed to avoid failures, increase lifespans, and reduce maintenance costs of equipment and machinery. The broad scope of the contents will make this book interesting for academics and professionals working in the areas of non-destructive evaluation and condition monitoring.
Download or read book Effect of Shot Peening on Surface Fatigue Life of Carburized and Hardened AISI 9310 Spur Gears written by Dennis P. Townsend and published by . This book was released on 1982 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study on the Scuffing Performance of High power Spur Gears at Elevated Oil Temperatures written by James Walter Brenneman and published by . This book was released on 2013 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In this study, a number of spur gear tests were performed under high-power and high-temperature conditions representative of certain aerospace gearing applications. As the first type of tests, long cycle tests of 100 million cycles were performed at set operating speed, load, and temperature conditions. The second type of tests, load-staged scuffing tests, implemented an incrementally increased torque schedule under constant speed and oil temperature conditions. Two different gear tooth surfaces were considered in these tests: hard ground surfaces representative of rough, as machined gear surfaces and chemically polished gear surfaces that were an order of magnitude smoother than the ground surfaces. The primary failure mode of concern was scuffing of the contact surfaces due to temperature build up. The impact of surface roughness amplitudes, contact stress, and oil inlet temperature on scuffing failures were investigated. Effects of ramp up procedures for the speed and torque, as well as the introduction of a break-in test stage were also investigated to show that they are critical to the scuffing performance of gears.
