Numerical Analysis on the Factors Affecting the Hydrodynamic Performance for the Parallel Surfaces With Microtextures

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Lei Wang ◽  
Wenzhong Wang ◽  
Hui Wang ◽  
Tianbao Ma ◽  
Yuanzhong Hu
Keyword(s):  
Numerical Analysis ◽  
Present Model ◽  
Surface Deformation ◽  
Numerical Procedure ◽  
Hydrodynamic Pressure ◽  
Hydrodynamic Performance ◽  
Factors Affecting ◽  
Cavitation Pressure ◽  
Parallel Surfaces ◽  
Semianalytical Method

A numerical analysis on the factors affecting the hydrodynamic performance for parallel surfaces with microtextures is presented in this paper. The semianalytical method and fast Fourier transform technique are implemented in the analysis. The numerical procedure is validated by comparing the results from the present model with the analytical solutions for the lubrication problem in an infinitewide sliding bearing with step-shaped textures. The numerical results show that the hydrodynamic performance can be greatly affected by the factors, such as the boundary conditions, cavitation pressure, microtextures, surface deformation, etc. This study can be of a great help for better understanding the mechanism of hydrodynamic pressure generated between parallel surfaces and realistically evaluating the improvement of tribological performance caused by textures.

Influence of Donut-Shaped Bump on the Hydrodynamic Lubrication of Textured Parallel Sliders

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Hao Fu ◽  
Jinghu Ji ◽  
Yonghong Fu ◽  
Xijun Hua
Keyword(s):  
Hydrodynamic Lubrication ◽  
Three Dimensional ◽  
Hydrodynamic Pressure ◽  
Hydrodynamic Performance ◽  
Geometrical Parameters ◽  
Textured Surfaces ◽  
Bump Height ◽  
Lubrication Performance ◽  
Parallel Surfaces ◽  
Vertical Spacing

The influence of donut-shaped bump texture on the hydrodynamic lubrication performance for parallel surfaces is presented in this paper. A mathematical equation has been applied to express the shape of three-dimensional donut-shaped bump texture. Numerical simulation of the pressure distribution of lubricant between a textured slider and a smooth, moving slider has been performed to analyze the geometrical parameters' influence on the hydrodynamic performance for textured surfaces. The numerical results show that the convex of the donut-shaped bump provides a microstep slider, which can form a convergent wedge and build up hydrodynamic pressure. Optimum values of horizontal spacing and bump height are obtained to maximize the hydrodynamic pressure. It is also noted that the average pressure increases monotonically with the increase of bump radius, but decreases with the increase of vertical spacing and dimple depth, respectively.

Vibro-Stone Column Reinforcement Mechanism and Numerical Analysis

2012 ◽  
Vol 446-449 ◽  
pp. 1940-1943
Author(s):  
Yang Liu ◽  
Hong Xiang Yan
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Pore Pressure ◽  
Numerical Procedure ◽  
Numerical Results ◽  
Excess Pore Pressure ◽  
Stone Column ◽  
Reinforcement Mechanism ◽  
Consolidation Theory ◽  
Excess Pore

Numerical simulation of vibro-stone column is taken to simulate the installation of vibro-stone column. A relationship based on test is adopted to calculate the excess pore pressure induced by vibratory energy during the installation of vibro-stone column. A numerical procedure is developed based on the formula and Terzaghi-Renduric consolidation theory. Finally numerical results of composite stone column are compared single stone column.

Elastohydrodynamic Lubrication of Soft-Layered Solids at Elliptical Contacts: Part 1: Elasticity Analysis

1994 ◽  
Vol 208 (1) ◽  
pp. 31-41 ◽  
Author(s):  
J Q Yao ◽  
D Dowson
Keyword(s):  
Aspect Ratio ◽  
Surface Deformation ◽  
Applied Pressure ◽  
Numerical Procedure ◽  
Elastohydrodynamic Lubrication ◽  
Thin Layers ◽  
Elasticity Analysis ◽  
Synovial Joint ◽  
Wide Range ◽  
Non Linear System

In this two-part paper we consider the elastohydrodynamic lubrication (EHL) of soft-layered solids representing elliptical contacts. The problem has not previously attracted much attention, partly due to the lack of an effective numerical procedure to solve the coupled non-linear system of equations, but it is essential to the proper design of bearings with soft elastomeric liners and the full understanding of synovial joint lubrication. In Part 1, the elasticity analysis for the surface deformation of a low elastic modulus layer on a hard-backing half-space under various forms of normal loadings is considered, by means of both the rigorous Hankel transform method and various simplifications. For layers of compressible materials (v ≤ 0.4), a generalized foundation model described by a second-order differential equation is proposed to represent the relationship between the surface deformation and the applied pressure. The empirical equation developed in this study is valid for a very wide range of the aspect ratio of the contact and provides an alternative way of modelling the elastic deformation without recourse to the often tedious integration in the numerical analysis of the EHL problem. The simplest form (constrained column model) of the equation, where the surface deformation is directly proportional to the local applied pressure, was found to be reasonably accurate for compressible thin layers (the aspect ratio 2b/ht ≥ 5 and Poisson's ratio v ≤ 0.4).

Numerical Analysis of Faults on Deep-Buried Tunnel Surrounding Rock Damaged Zones

2011 ◽  
Vol 90-93 ◽  
pp. 74-78 ◽  
Author(s):  
Jun Hu ◽  
Ling Xu ◽  
Nu Wen Xu
Keyword(s):  
Numerical Analysis ◽  
Mechanical Response ◽  
Progressive Failure ◽  
Process Analysis ◽  
Failure Process ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Factors Affecting ◽  
Rock Failure Process ◽  
Tunnel Instability

Fault is one of the most important factors affecting tunnel instability. As a significant and casual construction of Jinping II hydropower station, when the drain tunnel is excavated at depth of 1600 m, rockbursts and water inrush induced by several huge faults and zone of fracture have restricted the development of the whole construction. In this paper, a progressive failure progress numerical analysis code-RFPA (abbreviated from Rock Failure Process Analysis) is applied to investigate the influence of faults on tunnel instability and damaged zones. Numerical simulation is performed to analyze the stress distribution and wreck regions of the tunnel, and the results are consistent with the phenomena obtained from field observation. Moreover, the effects of fault characteristics and positions on the construction mechanical response are studied in details. Some distribution rules of surrounding rock stress of deep-buried tunnel are summarized to provide the reasonable references to TBM excavation and post-support of the drain tunnel, as well as the design and construction of similar engineering in future.

scholarly journals Numerical analysis of factors affecting condensation capacity of air-cooled condenser

2019 ◽  
Vol 227 ◽  
pp. 032030 ◽  
Author(s):  
Jinfeng Zhao ◽  
Zhongbao Feng ◽  
Zhongzhou Dou ◽  
Yingying Yao ◽  
Aijun Zhu ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Factors Affecting

scholarly journals An Efficient Numerical Procedure for Thermohydrodynamic Analysis of Cavitating Bearings

1996 ◽  
Vol 118 (3) ◽  
pp. 555-563 ◽  
Author(s):  
D. Vijayaraghavan
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Boundary Conditions ◽  
Radial Direction ◽  
Heat Dissipation ◽  
Numerical Procedure ◽  
Hydrodynamic Performance ◽  
Numerical Examples ◽  
Thermal Boundary Conditions ◽  
Theoretical Predictions

In this paper, an efficient and accurate numerical procedure to determine the thermo-hydrodynamic performance of cavitating bearings is described. This procedure is based on the earlier development of Elrod for lubricating films, in which the properties across the film thickness are determined at Lobatto points and their distributions are expressed by collocated polynomials. The cavitated regions and their boundaries are rigorously treated. Thermal boundary conditions at the surfaces, including heat dissipation through the metal to the ambient, are incorporated. Numerical examples are presented comparing the predictions using this procedure with earlier theoretical predictions and experimental data. With a few points across the film thickness and across the journal and the bearing in the radial direction, the temperature profile is very well predicted.

Numerical Analysis on Ground Pressure Feature in Fully Mechanized Coal Face

2013 ◽  
Vol 807-809 ◽  
pp. 2299-2303
Author(s):  
Wei Jian Yu ◽  
Tao Feng ◽  
Gang Ye Guo
Keyword(s):  
Numerical Analysis ◽  
Abutment Pressure ◽  
Numerical Procedure ◽  
Wall Rock ◽  
Coal Face ◽  
Distribution Form ◽  
Ground Pressure ◽  
Working Face ◽  
Set Up ◽  
Mining Height

Base on the fully mechanized coal face of 8113 (1) in LaoYingSan mine, numerical analysis method was applied to analyze the ground pressure feature, FLAC software is carried out to set up numerical model, and offer numerical procedure. The mining abutment pressure distribute form and its partition in front of fully mechanized working face. All four different mining height (2.6m2.8m3.0m3.2m) was respectively calculated. In addition, the influence of mining speed to mining abutment pressure and intervals is analyzed, four different mining distance (20m30m40m50m) selected separately. Afterwards, the different solution analyzed respectively, these results show that the mining abutment pressure distribution form in front of fully mechanized working face essentially identical, they including the stress increasing zones, the stress decreasing zones and the initial rock stress stable field. The influence of mining pace to wall rock looseness range greater than mining height.

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