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Paulo B. Lourenço - One of the best experts on this subject based on the ideXlab platform.

  • Masonry gravity dams : a numerical application for stability analysis
    2010
    Co-Authors: Eduardo M. Bretas, José V. Lemos, Paulo B. Lourenço
    Abstract:

    This work presents a numerical application for stability analysis of masonry gravity dams. From the geometrical dimensions, the material characteristics, hydrostatic Loads and seismic Loads, the application automatically determines the following results: thrust line for the dead weight Load and the dead weight together with the other Loads; stress diagram and safety factors for the failure of the damfoundation contact as part of an overall analysis; safety factors for the failure of horizontal planes along the body of the dam; parametric properties analysis (volumetric mass) and the resistant characteristics (friction angle) on the base of the dam. The analyses of three historical masonry dams located in Algeria was made. This work highlights the versatility of the numerical application as it can work with different section geometry, including curved and discontinuous sections, and the importance of assessing several scenarios in order to obtain a safe result.

Eduardo M. Bretas - One of the best experts on this subject based on the ideXlab platform.

  • Masonry gravity dams : a numerical application for stability analysis
    2010
    Co-Authors: Eduardo M. Bretas, José V. Lemos, Paulo B. Lourenço
    Abstract:

    This work presents a numerical application for stability analysis of masonry gravity dams. From the geometrical dimensions, the material characteristics, hydrostatic Loads and seismic Loads, the application automatically determines the following results: thrust line for the dead weight Load and the dead weight together with the other Loads; stress diagram and safety factors for the failure of the damfoundation contact as part of an overall analysis; safety factors for the failure of horizontal planes along the body of the dam; parametric properties analysis (volumetric mass) and the resistant characteristics (friction angle) on the base of the dam. The analyses of three historical masonry dams located in Algeria was made. This work highlights the versatility of the numerical application as it can work with different section geometry, including curved and discontinuous sections, and the importance of assessing several scenarios in order to obtain a safe result.

José V. Lemos - One of the best experts on this subject based on the ideXlab platform.

  • Masonry gravity dams : a numerical application for stability analysis
    2010
    Co-Authors: Eduardo M. Bretas, José V. Lemos, Paulo B. Lourenço
    Abstract:

    This work presents a numerical application for stability analysis of masonry gravity dams. From the geometrical dimensions, the material characteristics, hydrostatic Loads and seismic Loads, the application automatically determines the following results: thrust line for the dead weight Load and the dead weight together with the other Loads; stress diagram and safety factors for the failure of the damfoundation contact as part of an overall analysis; safety factors for the failure of horizontal planes along the body of the dam; parametric properties analysis (volumetric mass) and the resistant characteristics (friction angle) on the base of the dam. The analyses of three historical masonry dams located in Algeria was made. This work highlights the versatility of the numerical application as it can work with different section geometry, including curved and discontinuous sections, and the importance of assessing several scenarios in order to obtain a safe result.

Erwin V. Zaretsky - One of the best experts on this subject based on the ideXlab platform.

  • APPARATUS FOR STUDYING BALL SPINNING FRICTION
    2016
    Co-Authors: Steven T. Miller, Richard J. Parker, Erwin V. Zaretsky, T. Miller
    Abstract:

    I An experimental apparatus was designed and constructed'at the NASA Lewis Research Center^to study one aspect of spinning friction based on interfacial slip over the entire ball-race contact area. The apparatus is capable of measuring spinning moments of less than 0. 01 inch-pound at maximum Hertz contact stresses to over 400 000 psi, speeds to 3500 rpm, and under varying contact configurations and conditions. From the torque measurement, a coefficient of spinning friction can be calculated. | The apparatus comprises a drive assembly, a Dead-Weight Load assembly, a spheri-cal upper test specimen, a cylindrically grooved lower test specimen of varying confor-mity, a lower test specimen housing assembly incorporating a hydrostatic air-bearing assembly, and a torque-measuring system. In operation, the upper test specimen is Loaded against the lower test specimen through the drive shaft assembly by the Dead-Weight Load assembly. As the drive assembly is rotated, the upper test specimen ro-tates against the stationary lower test specimen actuating the torque-measuring system. [^Preliminary tests were conducted under varying Hertz stress to 136 000-psi maxi-mum Hertz stress at a spinning speed of 950 rpm, with a 51 percent ball-groove confor

Richard J. Parker - One of the best experts on this subject based on the ideXlab platform.

  • APPARATUS FOR STUDYING BALL SPINNING FRICTION
    2016
    Co-Authors: Steven T. Miller, Richard J. Parker, Erwin V. Zaretsky, T. Miller
    Abstract:

    I An experimental apparatus was designed and constructed'at the NASA Lewis Research Center^to study one aspect of spinning friction based on interfacial slip over the entire ball-race contact area. The apparatus is capable of measuring spinning moments of less than 0. 01 inch-pound at maximum Hertz contact stresses to over 400 000 psi, speeds to 3500 rpm, and under varying contact configurations and conditions. From the torque measurement, a coefficient of spinning friction can be calculated. | The apparatus comprises a drive assembly, a Dead-Weight Load assembly, a spheri-cal upper test specimen, a cylindrically grooved lower test specimen of varying confor-mity, a lower test specimen housing assembly incorporating a hydrostatic air-bearing assembly, and a torque-measuring system. In operation, the upper test specimen is Loaded against the lower test specimen through the drive shaft assembly by the Dead-Weight Load assembly. As the drive assembly is rotated, the upper test specimen ro-tates against the stationary lower test specimen actuating the torque-measuring system. [^Preliminary tests were conducted under varying Hertz stress to 136 000-psi maxi-mum Hertz stress at a spinning speed of 950 rpm, with a 51 percent ball-groove confor