86,520 research outputs found
A numerical approach for the analysis of deformable journal bearings
Get PDFThis paper presents a numerical approach for the analysis of hydrodynamic radial journal bearings. The effect of shaft and housing elastic deformation on pressure distribution within oil film is investigated. An iterative algorithm that couples Reynolds equation with a plane finite elements structural model is solved. Temperature and pressure effects on viscosity are also included with the Vogel-Barus model. The deformed lubrication gap and the overall stress state were calculated. Numerical results are presented with reference to a typical journal bearing configuration at two different inlet oil temperatures. Obtained results show the great influence of elastic deformation of bearing components on oil pressure distribution, compared with results for ideally rigid components obtained by Raimondi and Boyd solution
A numerical approach for static and dynamic analysis of deformable journal bearings
No full textThis paper presents a numerical approach for the static and dynamic analysis of hydrodynamic radial journal bearings. In the first part, the effect of shaft and housing deformability on pressure distribution within oil film is investigated. An iterative algorithm that couples Reynolds equation with a plane finite elements (FE) structural model is solved. Viscosity-to-pressure dependency (Vogel-Barus equation) is also included. The deformed lubrication gap and the overall stress state are obtained. Numerical results are presented with reference to a typical journal bearing configuration at two different inlet oil temperatures. Obtained results show the great influence of bearing components structural deformation on oil pressure distribution, compared with results for ideally rigid components. In the second part, a numerical approach based on perturbation method is used to compute stiffness and damping matrices, which characterize the journal bearing dynamic behavior
A numerical approach for static and dynamic analysis of deformable journal bearings
Get PDFThis paper presents a numerical approach for the static and dynamic analysis of hydrodynamic radial journal bearings. In the first part, the effect of shaft and housing deformability on pressure distribution within oil film is investigated. An iterative algorithm that couples Reynolds equation with a finite elements (FE) structural model is solved. Viscosity-to-pressure dependency (Vogel-Barus equation) is also included. The deformed lubrication gap and the overall stress state are obtained. Numerical results are presented with reference to a typical journal bearing configuration at two different inlet oil temperatures. Obtained results show the great influence of bearing components structural deformation on oil pressure distribution, compared with results for ideally rigid components. In the second part, a numerical approach based on perturbation method is used to compute stiffness and damping matrices, which characterize the journal bearing dynamic behavior
Studio numerico dell'effetto della deformabilità sul comportamento di cuscinetti idrodinamici
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Experimental evidences of a cylindrical journal bearing operating at very low Sommerfeld numbers
No full textIn this paper the experimental behavior of a cylindrical journal bearing working in critical conditions, namely at very low speed and high specific pressure, is described. A bearing with the nominal diameter of 160mm and the length of 145mm was used. The rotational speed was fixed at 60rpm (1Hz), while the applied load varied from 20kN to 350kN in the vertical direction, corresponding to the Sommerfeld number ranges from 0.1314 to 0.0086. Measurements of static position, hydrodynamic pressure, temperature profiles, and dynamic coefficients have been presented and discussed
Experimental evidence of a two-axial groove hydrodynamic journal bearing under severe operation conditions
Get PDFIn this study, an experimental investigation of the influence of the applied static load and rotational speed on the behaviour of a 160-mm diameter cylindrical journal bearing with two axial grooves was conducted. The rotational speed ranged from 66 rpm to 1440 rpm, and the applied static load varied from 0 kN to 350 kN in the vertical direction. The profiles of the pressure and the oil-film thickness during the shaft rotation have been measured by one proximity probe and one pressure probe installed in the rotating shaft. Measurements of the shaft centre position, dynamic coefficients, hydrodynamic pressure, temperature distributions on the bearing, film thickness, and bearing deformation under several operating conditions are presented and discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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