نتایج جستجو برای: failure analysis

تعداد نتایج: 3120164  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده مهندسی برق و کامپیوتر 1391

power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

Journal: :تحقیقات موتور 0
غلامحسین فرهی g.h. farrahi سید مصطفی حسنی گنگرج s.m. hassani gangaraj سعید ابوالحسنی s. abolhassani فرزاد همتی f. hemmati مهریار سخایی m. sakhaei

the premature breakage in some four cylinder diesel engine crankshafts was reported. all crankshafts were failed from the same region. failures had occurred in the first crankpin, the nearest crankpin to the flywheel. dynamic analysis and finite element modelling were carried out to determine the state of stress in the crankshaft. fem results revealed that the first crankpin fillet is the most ...

Journal: :تحقیقات مهندسی کشاورزی 0
امیر صمدی دانشجوی دکتری پردیس کشاورزی و منابع طبیعی دانشگاه تهران ابراهیم امیری تکلدانی استادیار پردیس کشاورزی و منابع طبیعی دانشگاه تهران حسن رحیمی استاد پردیس کشاورزی و منابع طبیعی دانشگاه تهران

riverbank erosion, land loss and associated sedimentation are river engineering and water resources management problems of global significance. the ability to predict riverbank stability on eroding rivers is the prerequisite of developing a channel width adjustment model and is essential for estimating riverbank erosion and associated sedimentation. in this research, a detailed model for stabil...

Journal: :international journal of advanced design and manufacturing technology 0
suresh babu valeru mr tarasasanka cherukuri mr

in this study, behavior of pin-loaded glass fiber reinforced with polyethylene laminated composites with different stacking sequence and different dimensions has been observed experimentally and stress analysis was performed using ansys software. the aim is to investigate stresses, failure strength and failure mode of composite laminates containing a pin loaded hole when the material exhibits l...

Journal: :journal of electrical and computer engineering innovations 0
shiva taghipour department of electrical engineering, university of guilan, rasht, iran rahebeh niaraki asli department of electrical engineering, university of guilan, rasht, iran

due to the expected increase of defects in circuits based on deep submicron technologies, reliability has become an important design criterion. although different approaches have been developed to estimate reliability in digital circuits and some measuring concepts have been separately presented to reveal the quality of analog circuit reliability in the literature, there is a gap to estimate re...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علم و صنعت ایران - دانشکده مهندسی مکانیک 1385

در این رساله با به کارگیری فرآیند fmea (failure mode and effect analysis و با نگاهی چند جانبه و علت گرا ریشه های احتمالی خرابی یک پمپ گریز از مرکز با سرویس lpg مورد بررسی و مطالعه قرار گرفته است. ابتدا با جمع آوری و بررسی آمار خرابی 368 پمپ در یک دوره هشت ساله، پمپ با بیشترین آمار خرابی به عنوان یک نمونه مطالعاتی انتخاب شد و با بررسی مستندات مربوط به فعالیت های تعمیراتی پمپ مذکور، مشخص شد که...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه زنجان - دانشکده علوم انسانی و اجتماعی 1392

most specialists in the field of foreign language teachingconsiderreading skill as an interactive process between the reader’s prior knowledge and the text.accordingly, the activation of prior knowledge for an effective comprehension is very important. it is generally agreed that the pre-reading phase is the stage where this type of interaction and activation may be enhanced throughcertain stra...

Journal: :journal of occupational health and epidemiology 0
s mahdavi faculty member ,department of occupational health engineering, school of health, lorestan university of medical sciences, khorramabad, iran. p rasti pisheh student of occupational hygiene engineering, tehran university of medical sciences, tehran, iran m jozekanaani senior occupational hygienist, governing health section, hse main office, national iranian gas company (nigc), tehran, iran

background: the reliability and safety of gas refineries are strongly associated with the reliability of other parts of the system. defect and failure in one part of a system can cause total system breakdown or accident. the failure and damage in these equipment such as transformers and boilers results in not only the equipment damage and human injuries but also productivity reduction. the purp...

Journal: :iranian endodontic journal 0
shahram azimi parisa delvari hamid cyrus hajarian mohammad ali saghiri kasra karamifar mehrdad lotfi

introduction: this study investigated the fatigue and fracture modes of race and protaper rotary instruments. materials & methods: fatigue resistance was evaluated by rotating the files 30 ° or 60 ° and with 2 or 5mm radius of curvature. race taper 06 size 25 and protaper f1 files (n=40) were used. the number of rotations to failure was analyzed by two-way anova and independent sample     t-tes...

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