No description available.

No description available.

Micropitting is a form of surface contact fatigue encounteredin bearingsa nd gears, under lubricating conditions, which lead to their premature failure. All gears are susceptible to micropitting, including spur, helical and bevel. Micropitting can occur with all heatt reatmentsa ppliedt o gearsa nd with both, synthetica nd mineral lubricants. It can occur after a relatively short period of operation and, after a certain number of cycles,g earsn eedt o be replacedd ue to the increasedn oisea nd vibrations causedb y the deviations of the tooth profile. Continuing operation of affected gears can lead to a catastrophic type of failure (i. e., tooth breakage). These considerations explain the increasing current interest in micropitting. It has been reported that micropitting in bearings is associated with a specific microstructural transformation in steel, i. e. martensite decay. However, to the authoes knowledge, this transformation has not been reported in gears. In the present work, extensive metallurgical investigations have been carried out and they revealed that the same transformation occurs in gears. The aim of this project was to describe the mechanism of micropitting by taking into account the influence of several controlling factors such as, material, surface finish, lubricant, load, temperature,s peeda nd, slide-to-roll ratio. Their influence is assessed with a fractional factorial experimentadl esign.S everaln on-destructivete chniquesh ave been used in order to monitor the specimen condition during and after running, such as X-ray diffraction, optical profilometry, light microscopy. The mechanical properties of the products of martensite decay, known as dark etching regions, white etching bands and butterflies are highly relevant to the fatigue behaviour of the steel. Nanoindentation and AFM techniquesh aveb eenu sedt o determinet hesep roperties. A micropitting mechanism correlated with the mechanism of martensite decay in gears is suggestedb asedo n thesea nalyses.

No description available.

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 94-97). / xi, 97 leaves, bound ill. (some col.) 29 cm

Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 62-66).

Thesis (M.Sc.)--York University, 2005. Graduate Programme in Kinesiology and Health Science. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://proquest.umi.com/pqdweb?index=0&did=1176560151&SrchMode=1&sid=17&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1195154078&clientId=5220

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains v, 88 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 57-59).

Thèse (M.Sc.)--Université Laval, 2008. / Bibliogr. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.

Thesis (D.Eng.)--Cleveland State University, 2008. / Abstract. Title from PDF t.p. (viewed on Oct. 8, 2008). Includes bibliographical references (p. 91-99). Available online via the OhioLINK ETD Center. Also available in print.