Characteristic analysis of journal bearing under thin film lubrication—Layered Viscosity Model
Journal bearing is a kind of widely used bearing and its study never stops. The analysis is carried to journal bearing with layered viscosity model in this paper. Layered Viscosity Model regards viscosity as piecewise function and averages every segment in order to get more accurate expression, and the pressure distributing, load capacity and friction are obtained for journal sliding bearing under thin film lubrication. The condition of thin film lubrication actualizing is made certain. The theoretical base is provided for the analysis of aggradation and liniment surface layer lubrication. This work could promote the understanding and research of the mechanism of the nano - scale thin film lubrication.
Research on Mechanical Deformation of Thrust Bearing
Finite Element Method numerical simulation has been carried out to analyze mechanical deformation of thrust bearing under the point and line supporting condition. The simulation results indicate that the torsion deformation of the point supporting is the larger, torsion deformation is mainly radial bending deformation, and circumferential bending deformation is small, it becomes more and more obvious with the decrease of bearing pad length-width ratio under the same working conditions for the same pad. Line supporting torsion deformation is mainly the circumferential bending deformation, and the left and right sides are symmetrical along the circumferential, the radial bending deformation is small, torsion deformation related to the length and width of supporting, with their size increasing the torsion deformation decreased.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.