Thermal Fatigue
Mostrando 13-24 de 34 artigos, teses e dissertações.
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13. Influência da oxidação térmica sobre as propriedades de fadiga da liga Ti-6Al-4V
Esta dissertação, investiga o comportamento em fadiga da liga Ti-6Al-4V após o tratamento superficial denominado oxidação térmica, para aplicação em pinos fusíveis mecânicos. A oxidação térmica controlada do titânio e suas ligas apresenta propriedades interessantes na resistência à corrosão-desgaste, devido a sua alta estabilidade e dureza,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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14. A fatigue life prediction model of welded joints under combined cyclic loading. / Um modelo para previsão de vida à fadiga de juntas soldadas submetidas a carregamentos combinados.
The main purpose of this work is to develop a practical and robust methodology to evaluate the fatigue life in seam weld joints fabricated with GMAW process when subjected to combine cyclic loading. The maximum linear stress at the typical crack initiation region, better known as hot spot stress, was used to calculate the fatigue life through high cycle fati
Publicado em: 2010
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15. Efeito do protetor solar sobre a fadiga durante a corrida com exposição ao sol
Sunscreens may be water and sweat resistant, but it is unknown if they affect the production, secretion and evaporation of sweat and, hence, impair human thermoregulation. During prolonged or mild duration exercises, mainly those carried out in hot environments, thermoregulation plays a key role in the development of fatigue. If sunscreens indeed interfere w
Publicado em: 2009
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16. O uso do boné em crianças durante a corrida de intensidade auto regulada sob o sol diminui a temperatura média da cabeça, mas não influencia a velocidade da corrida
The aim of this study was to test the hypothesis that the use of the cap could be a barrier to sun radiation, allowing less heat storage during the self paced race of 6 km under sunlight. Nineteen children of both sexes, inhabitants of tropical region, healthy and able to practice physical exercise (10.3 ± 0.7 and 10.2 ± 1.0 years old, 148 ± 6 and 145 ±
Publicado em: 2009
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17. Estudo de propagaÃÃo de fratura em compÃsitos odontolÃgicos utilizando tomografia por coerÃncia Ãptica / Crack propagation study in dental composites by optical coherence tomography
Contemporary approaches to fatigue principles consider a fracture process in three phases: crack initiation, slow crack growth, and fast fracture. The purpose of this study was to analyze the sites of fracture initiation and slow crack propagation in a fiber reinforced composite, using images produced by the optical coherence tomography. The traditional micr
Publicado em: 2008
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18. Fadiga termomecânica em ligas de ferro fundido cinzento para discos de freio automotivos / Thermomechanical fatigue in gray cast iron alloys to automotive brake discs
Brake discs are submitted to thermal and mechanical stress that can be relatively high during abrupt braking action happens (fractions of seconds), causing the temperature to reach values as high as 600ºC. This temperature variation results in thermal shocks that can generate cracks and/or a large amount of plastic deformation in the disk. The main aim of t
Publicado em: 2007
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19. Suplementação com aminoácidos de cadeia ramificada (AACR): efeitos sobre o desempenho físico no calor em humanos
There are evidences that serotonin is linked to central fatigue processes and in hyperthermic stress its activity is enhanced. In order to diminish central serotonergic activation and improve performance, nutritional strategies with branched-chain amino acids (BCAA) has sought to prevent tryptophan influx to CNS, because these amino acids compete amongst the
Publicado em: 2007
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20. Sistema colinérgico central modula os ajustes dos sistemas cardiovascular e termorregulatório induzidos pelo exercício físico até a fadiga
ABSTRACT The purpose of this study was to verify if the cardiovascular and thermoregulatory adjustments mediated by central cholinergic receptors and peripheral cathecolamines during the physical exercise until fatigue. Wistar rats weighting 278 ± 5 g, were submitted to bilateral adrenodemedullation (ADM) or sham (SHAM) surgery. After recovery, the animals
Publicado em: 2007
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21. Evaluation of asphalt mixtures produced with conventional peruvian asphalt binder PEN 60/70 and SBS polymer-modified type I 60/60 and PG 76-22 / Avaliação de misturas produzidas com ligantes asfálticos peruanos convencional PEN 60/70 e modificados por polímero SBS tipo I 60/60 e PG 76-22
The main goal of this work is the evaluation of the behavior of conventional peruvian asphalt binder AC PEN 60/70 and SBS polymer-modified asphalts I 60/60 and PG 76-22, when used in hot-mix asphalt (HMA), under both conditions with and without short-term aging. It aims also to establish the asphalt binder performance grade (PG), which is based on the weathe
Publicado em: 2007
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22. Some observations on wear and damages in cemented carbide tools
Cutting tools are subjected to extremely unfavorable conditions during machining operations. High cutting temperatures, compressive and shearing stresses, chemical attacks, variable cyclic thermal and mechanical loads are some adverse conditions that wear and damage these tools. Therefore, it is crucial to understand the process of tool wear and damage and h
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2006-09
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23. Avaliação do efeito do Mg nas propriedades de fadiga em alta temperatura de ligas de Al-Si fundidas sob pressão em molde permanente / Magnesium addition effect on high temperature fatigue properties of permanent mold cast Al-Si alloys
Gear Box housings are usually subjected to cyclic stresses generated during engine operation. Such stresses are more critical at high temperatures and long times. Thermal gradients induced within the components submitted to variation of temperature during working may result in internal stresses and strains. Thermal cycling can result in crack nucleation and
Publicado em: 2006
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24. Desgaste e fadiga térmica de ligas aço matriz + NbC. / Wear and thermal fatigue of matrix steel + NbCalloys.
The concept of ?matrix steel + NbC? was used to cast alloys with the M2 steel matrix (0,5%C ? 2%W ? 3%Mo ? 4,6%Cr ? 1%V) and different volume fractions of niobium carbides. Niobium (2,5 e 5%) and stoichiometric carbon were added to produce NbC carbides and titanium (0,1%) to modify de NbC carbides morphology. NbC presented three basic morphologies: Chinese s
Publicado em: 2006