NEURAL NETWORK MODELING FOR ESTIMATION OF SCOUR DEPTH AROUND BRIDGE PIERS

It is essential to predict the scour depth around bridge piers for hydraulic engineers involved in the economical design of bridge pier foundation. Conventional investigations have long been of the opinion that empirical scour prediction equations based on laboratory data over predict scour depths. In this article, the Back-Propagation Neural Network (BPN) was applied to predict the scour depth in order to overcome the problem of exclusive and the nonlinear relationships. The observations obtained from thirteen states in USA was verified by the present model. From the comparison with conventional experimental methods, it can be found that the scour depth around bridge piers can be efficiently predicted using the BPN.     

Thermohydrodynamic Analysis and Design of Dual Conical-Cylindrical Bearings Using Non-Newtonian Lubricants

In this study, further analysis and design of the hydraulic servo cylinder using dual conical-cylindrical bearings with practical dimensions are considered, and the dimensional forms can be used to express the bearing performance parameters. The film viscosity is formulated as an exponential function of temperatures and pressures. The power law, the non-Newtonian lubricant, the modified Reynolds equation, and thermohydrodynamic (THD) boundary conditions are the basic assumptions of this analysis. Effects of the eccentricity and tilt angle are considered herein.     

Analysis of Viscosity Interaction and Heat Transfer on the Dual Conical-Cylindrical Bearing©

Viscosity is an essential property in hydrodynamic lubrication. In general, the lubricant is not considered to have uniform viscosity within a given bearing. The viscosity of the lubricant is affected by both pressure and temperature. The viscosity of the lubricant increases with pressure and, for most lubricants, this effect is much larger than that of temperature or shear when the pressure is significantly above atmospheric pressure. This study analyzes the thermal effect of dual conical-cylindrical bearing performance parameters via the viscosity-pressure-temperature relationships of lubricants. The results reveal that pressure increases both the film viscosity and temperature.