Influence of micro-grooves on the lubrication performance of a misaligned bearing

2019 ◽  
Vol 234 (6) ◽  
pp. 887-899
Author(s):  
Yanxiang Han ◽  
Yonghong Fu
Keyword(s):  
Angular Position ◽  
Surface Texturing ◽  
Mass Conservation ◽  
Groove Depth ◽  
Film Rupture ◽  
Practical Applications ◽  
Numerical Predictions ◽  
Lubrication Performance ◽  
Load Carrying ◽  
Manufacturing Tolerances

Surface texturing for improving the lubrication performance of journal bearings has been widely investigated in the last two decades. In practical applications, the misalignment of a journal bearing occurs due to the asymmetric bearing load, elastic deflection, manufacturing tolerances, and installation errors. However, there has been little discussion on the influence of grooves on the lubrication performance of misaligned bearings. In the present work, numerical predictions of lubrication performances are presented to test the influence of the grooves. Based on the JFO boundary condition, a mass conservation algorithm is implemented to automatically determine the position of oil film rupture and reformation. The load-carrying capacity, friction force, friction coefficient, and bearing moment are computed numerically. The influence of angular position of the groove is first conducted in a misaligned bearing. Subsequently, the groove depth and width are investigated with different values of [Formula: see text] and [Formula: see text] ratios, respectively.

scholarly journals Numerical Analysis of the Bond Strength between Two Methacrylic Polymers by Surface Modification

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3927
Author(s):  
Joanna Taczała ◽  
Katarzyna Rak ◽  
Jacek Sawicki ◽  
Michał Krasowski
Keyword(s):  
Numerical Analysis ◽  
Bond Strength ◽  
Angular Position ◽  
Fem Analysis ◽  
Groove Depth ◽  
Chemical Reagent ◽  
Shear Process ◽  
3D Geometry ◽  
The Right ◽  
Artificial Teeth

The creation of acrylic dentures involves many stages. One of them is to prepare the surfaces of artificial teeth for connection with the denture plates. The teeth could be rubbed with a chemical reagent, the surface could be developed, or retention hooks could be created. Preparation of the surface is used to improve the bond between the teeth and the plate. Choosing the right combination affects the length of denture use. This work focuses on a numerical analysis of grooving. The purpose of this article is to select the shape and size of the grooves that would most affect the quality of the bond strength. Two types of grooves in different dimensional configurations were analyzed. The variables were groove depth and width, and the distance between the grooves. Finally, 24 configurations were obtained. Models were analyzed in terms of their angular position to the loading force. Finite element method (FEM) analysis was performed on the 3D geometry created, which consisted of two polymer bodies under the shear process. The smallest values of the stresses and strains were characterized by a sample with parallel grooves with the grooving dimensions width 0.20 mm, thickness 0.10 mm, and distance between the grooves 5.00 mm, placed at an angle of 90°. The best dimensions from the parallel (III) and cross (#) grooves were compared experimentally. Specimens with grooving III were not damaged in the shear test. The research shows that the shape of the groove affects the distribution of stresses and strains. Combining the selected method with an adequately selected chemical reagent can significantly increase the strength of the connection.

scholarly journals Bending Response of 3D-Printed Titanium Alloy Sandwich Panels with Corrugated Channel Cores

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 556
Author(s):  
Zhenyu Zhao ◽  
Jianwei Ren ◽  
Shaofeng Du ◽  
Xin Wang ◽  
Zihan Wei ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Heat Dissipation ◽  
Sandwich Panels ◽  
Face Sheet ◽  
Collapse Mechanism ◽  
Corrugated Channel ◽  
Four Point Bending ◽  
Numerical Predictions ◽  
Load Carrying ◽  
3D Printed

Ultralight sandwich constructions with corrugated channel cores (i.e., periodic fluid-through wavy passages) are envisioned to possess multifunctional attributes: simultaneous load-carrying and heat dissipation via active cooling. Titanium alloy (Ti-6Al-4V) corrugated-channel-cored sandwich panels (3CSPs) with thin face sheets and core webs were fabricated via the technique of selective laser melting (SLM) for enhanced shear resistance relative to other fabrication processes such as vacuum brazing. Four-point bending responses of as-fabricated 3CSP specimens, including bending resistance and initial collapse modes, were experimentally measured. The bending characteristics of the 3CSP structure were further explored using a combined approach of analytical modeling and numerical simulation based on the method of finite elements (FE). Both the analytical and numerical predictions were validated against experimental measurements. Collapse mechanism maps of the 3CSP structure were subsequently constructed using the analytical model, with four collapse modes considered (face-sheet yielding, face-sheet buckling, core yielding, and core buckling), which were used to evaluate how its structural geometry affects its collapse initiation mode.

The Effect of Journal Bearing Misalignment on Load and Cavitation for Non-Newtonian Lubricants

1986 ◽  
Vol 108 (4) ◽  
pp. 645-654 ◽  
Author(s):  
R. H. Buckholz ◽  
J. F. Lin
Keyword(s):  
Reynolds Equation ◽  
Numerical Solutions ◽  
Journal Bearings ◽  
Surface Boundary ◽  
Film Rupture ◽  
Aspect Ratios ◽  
Free Surface Boundary Condition ◽  
Load Carrying ◽  
Boundary Location ◽  
Surface Boundary Condition

An analysis for hydrodynamic, non-Newtonian lubrication of misaligned journal bearings is given. The hydrodynamic load-carrying capacity for partial arc journal bearings lubricated by power-law, non-Newtonian fluids is calculated for small valves of the bearing aspect ratios. These results are compared with: numerical solutions to the non-Newtonian modified Reynolds equation, with Ocvirk’s experimental results for misaligned bearings, and with other numerical simulations. The cavitation (i.e., film rupture) boundary location is calculated using the Reynolds’ free-surface, boundary condition.

The Validity of the Reynolds Equation in Modeling Hydrostatic Effects in Gas Lubricated Textured Parallel Surfaces

2005 ◽  
Vol 128 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Y. Feldman ◽  
Y. Kligerman ◽  
I. Etsion ◽  
S. Haber
Keyword(s):  
Carrying Capacity ◽  
Reynolds Equation ◽  
Stokes Equations ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Physical Parameters ◽  
Load Carrying Capacity ◽  
Wide Range ◽  
Load Carrying ◽  
Parallel Surfaces

Microdimples generated by laser surface texturing (LST) can be used to enhance performance in hydrostatic gas-lubricated tribological components with parallel surfaces. The pressure distribution and load carrying capacity for a single three-dimensional dimple, representing the LST, were obtained via two different methods of analysis: a numerical solution of the exact full Navier-Stokes equations, and an approximate solution of the much simpler Reynolds equation. Comparison between the two solution methods illustrates that, despite potential large differences in local pressures, the differences in load carrying capacity, for realistic geometrical and physical parameters, are small. Even at large clearances of 5% of the dimple diameter and pressure ratios of 2.5 the error in the load carrying capacity is only about 15%. Thus, for a wide range of practical clearances and pressures, the simpler, approximate Reynolds equation can safely be applied to yield reasonable predictions for the load carrying capacity of dimpled surfaces.

Mutual influence of plateau roughness and groove texture of honed surface on frictional performance of piston ring–liner system

2016 ◽  
Vol 231 (7) ◽  
pp. 838-859 ◽  
Author(s):  
Yang Hu ◽  
Xianghui Meng ◽  
Youbai Xie ◽  
Jiazheng Fan
Keyword(s):  
Piston Ring ◽  
Cylinder Liner ◽  
Texture Features ◽  
Groove Depth ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Lubrication Performance ◽  
Liner System ◽  
Frictional Performance

The cylinder liner surface finish, which is commonly produced using the honing technique, is an essential factor of engine performance. The characteristics of the texture features, including the cross-hatch angle, the plateau roughness and the groove depth, significantly affect the performance of the ring pack–cylinder liner system. However, due to the influence of the honed texture features, the surface roughness of the liner is not subject to Gaussian distribution. To simulate the mixed lubrication performance of the ring–liner system with non-Gaussian roughness, the combination of a two-scale homogenization technique and a deterministic asperities contact method is adopted. In this study, a one-dimensional homogenized mixed lubrication model is established to study the influence of groove parameters on the load-carrying capacity and the frictional performance of the piston ring–liner system. The ring profile, plateau roughness, and operating conditions are taken into consideration. The main findings are that for nonflat ring, shallow and wide groove textures are beneficial for friction reduction, and there exists an optimum groove density that makes the friction minimum; for flat ring, wide and sparse grooves help improving the tribological performance, and there exists an optimum groove depth that makes the friction minimum.

scholarly journals Porosity Elimination in Modified Direct Laser Joining of Ti6Al4V and Thermoplastics Composites

2019 ◽  
Vol 9 (3) ◽  
pp. 411 ◽  
Author(s):  
Haipeng Wang ◽  
Yang Chen ◽  
Zaoyang Guo ◽  
Yingchun Guan
Keyword(s):  
Glass Fiber ◽  
Fracture Strength ◽  
Joint Strength ◽  
Surface Texturing ◽  
Practical Applications ◽  
Laser Joining ◽  
Glass Fiber Reinforced ◽  
Hybrid Joints ◽  
Direct Laser ◽  
Joining Process

Hybrid lightweight components with strong and reliable bonding qualities are necessary for practical applications including in the automotive and aerospace industries. The direct laser joining method has been used to produce hybrid joints of Ti6Al4V and glass fiber reinforced polyamide (PA66-GF30). Prior to the laser joining process, a surface texturing treatment is carried out on Ti6Al4V to improve joint strength through the formation of interlock structures between Ti6Al4V and PA66-GF30. In order to reduce the generated micro-pores in Ti6Al4V-PA66-GF30 joints, a modified laser joining method has been proposed. Results show that only very few small micro-pores are generated in the joints produced by the modified laser joining method, and the fracture strength of the joints is significantly increased from 13.8 MPa to 41.5 MPa due to the elimination of micro-pores in the joints.

scholarly journals Effects of bushing profiles on the elastohydrodynamic lubrication performance of the journal bearing under steady operating conditions

2019 ◽  
Vol 20 (2) ◽  
pp. 207 ◽  
Author(s):  
Chongpei Liu ◽  
Bin Zhao ◽  
Wanyou Li ◽  
Xiqun Lu
Keyword(s):  
Journal Bearing ◽  
Elastohydrodynamic Lubrication ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Parabolic Profile ◽  
Leakage Flow Rate ◽  
Lubrication Performance ◽  
Load Carrying ◽  
Edge Wear ◽  
Flow Rate Change

The bushing profiles have important effects on the performance of journal bearing. In this article, the effects of plain profile, double conical profile, and double parabolic profile on the elastohydrodynamic lubrication of the journal bearing under steady operating conditions are investigated. The journal misalignment and asperity contact between journal and bushing surface are considered, while the modification of the bushing profiles due to running-in is neglected. Finite element method is used for the elastic deformation of bushing surface, while the numerical solution is established by using finite difference method and overrelaxation iterative method. The numerical results reveal that the double parabolic profile with appropriate size can significantly increase the minimum film thickness and reduce the asperity contact pressure and friction, while the maximum film pressure, load-carrying capacity, and leakage flow rate change slightly under steady operating conditions. This study may help to reduce the edge wear and prolong the service life of the journal bearing.

Tribological performance of textured parallel sliding contact under mixed lubrication condition by considering mass conservation condition and couple-stress parameter

2020 ◽  
pp. 135065012094508
Author(s):  
Annadi Ramana Reddy ◽  
Syed Ismail
Keyword(s):  
Couple Stress ◽  
Surface Texturing ◽  
Frictional Coefficient ◽  
Mass Conservation ◽  
Tribological Performance ◽  
Mixed Lubrication ◽  
Numerical Code ◽  
Performance Parameters ◽  
Mixed Lubrication Regime ◽  
Surface Modification Techniques

To enhance the tribological performance of mechanical parts, one of the reliable methods is surface topography modification, in which the surface of one/both interacting contacts were to be modified. Surface texturing is one of the surface modification techniques. In the present work, a numerical code is developed to address the effect of texture shape (elliptical and triangular), size and distribution (parallel and zigzag) on the tribological performance parameters (minimum film thickness, percentage of hydrodynamic load from the total generated pressure and frictional coefficient) under mixed lubrication regime for a known value of load support. In the present analysis, the mass conservative, i.e. Jakobson-Floberg-Ollson (JFO) cavitation condition and couple stresses of lubricant are considered. In addition, surface irregularities are considered by using the flow factors of Patir-Cheng model. The results show that texture shape has a significant effect, whereas the texture distribution has a slight effect on the tribological performance parameters. Moreover, the couple stress of lubricant has a prominent effect on the tribological performance.

Effects of double parabolic profiles with groove textures on the hydrodynamic lubrication performance of journal bearing under steady operating conditions

2020 ◽  
Vol 21 (3) ◽  
pp. 301
Author(s):  
Chongpei Liu ◽  
Wanyou Li ◽  
Xiqun Lu ◽  
Bin Zhao
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Operating Conditions ◽  
Lubricating Oil ◽  
Asperity Contact ◽  
Adiabatic Flow ◽  
Lubrication Performance ◽  
Load Carrying ◽  
Edge Wear ◽  
Journal Misalignment

The textures on the bushing surface have important effects on the performance of journal bearing. In this study, the effects of double parabolic profiles with groove textures on the hydrodynamic lubrication performance of journal bearing under steady operating conditions are investigated theoretically. The journal misalignment, asperity contact and thermal effects are considered, while the profile modifications due to running-in are neglected. The Winkler/Column model is used to calculate the elastic deformation of bushing surface and the adiabatic flow hypothesis is adopted to obtain the effective temperature of lubricating oil. The numerical solution is established by using finite difference and overrelaxation iterative methods, and the rupture zone of oil film is determined by Reynolds boundary conditions. The numerical results reveal that the double parabolic profiles with groove textures with proper location and geometric sizes can increase load carrying capacity and reduce friction loss under steady operating conditions, which effectively overcome the drawbacks of double parabolic profiles. This novel bushing profile may help to reduce the bushing edge wear and enhance the lubrication performance of journal bearing.

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