Numerical Analysis for Influence of Plastic and Elastic Deformation of Rough Surfaces on PEHL for Line Contacts

Tribology ◽  
2005 ◽  
Author(s):  
R. J. Niu ◽  
P. Huang
Keyword(s):  
Plastic Deformation ◽  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Paper Analysis ◽  
Line Contact ◽  
Plastic Deformations ◽  
Rolling Contacts ◽  
Line Contacts ◽  
Elastic And Plastic Deformations ◽  
Strain Relationship

In the present paper, analysis of elasto-plasto-hydrodynamic lubrication (PEHL) in the line contact is carried out to investigate the effect of heavily loaded roll-over on the change in profile of indents. The pressure and film thickness profiles are obtained to solve the Reynolds and film thickness equations simultaneously. And, both the elastic and plastic deformations of the contact, featured with an indent, have been considered. A multi-grid numerical algorithm used in EHL of line contacts is modified and then used for the oil lubricated rolling contacts. In the program, stress and plastic deformation of the indent profile are calculated with the hardening plastic stress-strain relationship according to the theories of plasticity when pressure excesses the yield stress. The results, with and without considering plastic deformation, are compared to show the different influences on the pressure and film thickness. Analysis shows that since the plastic deformation will change the surface roughness, it will significantly change the pressure but film thickness.

Reflections on Some Aspects of Lubrication of Concentrated Line Contacts

1979 ◽  
Vol 101 (4) ◽  
pp. 528-531 ◽  
Author(s):  
P. H. Markho ◽  
D. B. Clegg
Keyword(s):  
Film Thickness ◽  
Curve Fitting ◽  
Line Contact ◽  
Intermediate Region ◽  
Force Component ◽  
Pressure Force ◽  
Tangential Pressure ◽  
Method Of Least Squares ◽  
End Conditions ◽  
Line Contacts

New formulas are presented for two important lubrication parameters of a flooded, concentrated line contact, namely the tangential pressure force component under elasto-hydrodynamic (EHD) conditions and the film thickness in the “intermediate” region defined by Dowson and Whitaker [1]. The latter region, which separates the rigid-isoviscous region from the elastic-piezoviscous (or EHD) region, has not, so far, been represented by an equation. The first formula was obtained simply by curve-fitting, using the method of least squares, from data largely available in the published literature; while the second is basically a third degree Hermite osculating polynomial with four end conditions.

Effect of elastic and plastic deformations on tribological behavior of graphene-reinforced Ni3Al matrix composites

2017 ◽  
Vol 232 (10) ◽  
pp. 1261-1272 ◽  
Author(s):  
Yuchun Huang ◽  
Xiaoliang Shi ◽  
Kang Yang ◽  
Jialiang Zou ◽  
Qiao Shen ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Tribological Properties ◽  
Tribological Behavior ◽  
Tribological Performance ◽  
Plastic Deformations ◽  
Wear Resistant ◽  
Elastic And Plastic Deformations ◽  
Resistant Layer ◽  
Al Matrix ◽  
Self Lubricating Composites

The elastic and plastic deformations have significant effect on the tribological properties of the graphene-reinforced Ni3Al matrix self-lubricating composites. The primary purpose of this study is to investigate the tribological behavior and wear mechanisms of graphene-reinforced Ni3Al matrix self-lubricating composites by researching the effects of different loads and the corresponding friction heat on the elastic or plastic deformation. The dry sliding tribology tests of graphene-reinforced Ni3Al matrix self-lubricating composites are carried out at the loads of 7, 10, 13, and 16N, respectively. The elastic or plastic deformation is judged by comparing the yield stress with the contact stress analyzed by the numerical simulation method. It is found that graphene-reinforced Ni3Al matrix self-lubricating composites exhibit good tribological properties at 13 N due to the elastic deformation, leading to the formation of relatively stable wear resistant layer. Graphene-reinforced Ni3Al matrix self-lubricating composites show poor tribological performance at 16 N for the plastic deformation, resulting in the destruction of the wear resistant layer and the generation of surface cracks and material spalling. From the mechanical mechanism of wear, the plastic deformation and thermal stress are the important factors to lead to the material spalling. The results could be used to guide the selection of suitable working conditions for having good tribological performance of low wear and long service life.

Elastoplastohydrodynamic Lubrication with Dent Effects

1996 ◽  
Vol 210 (4) ◽  
pp. 233-245 ◽  
Author(s):  
G Xu ◽  
D A Nickel ◽  
F Sadeghi ◽  
X Ai
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Line Contact ◽  
Sliding Contacts ◽  
Element Analysis ◽  
Elastic Case ◽  
Local Material

A line contact elastoplastohydrodynamic lubrication (EPHL) model has been developed to investigate the effect of a dent on heavily loaded rolling/sliding contacts. The Jinite element analysis (FEA) was used to obtain the plastic deformation of the surfaces caused by the high-pressure spikes that occur in the contact due to the presence of a dent. The effects of various dent sizes on the pressure and film thickness were studied. The results indicate that by including the plastic deformation of the surfaces in the analysis, the pressure spikes that occur due to a dent in the contact are smaller than those of the purely elastic case, and local material yielding occurs, resulting in bumps at the edges of the dent. Effects of diflerent bump shapes at the dent edges were then studied in elastohydrodynamic lubrication (EHL) contacts and the results indicated that these bumps can reduce the magnitude of pressure spikes.

Estimation of Minimum Thickness for Line Contacts in the Transition Region between the Isoviscous—Elastic and the Piezoviscous-Elastic Lubrication Regimes

1989 ◽  
Vol 203 (6) ◽  
pp. 379-386 ◽  
Author(s):  
M J Jaffar
Keyword(s):  
Film Thickness ◽  
Transition Region ◽  
Approximate Formula ◽  
Line Contact ◽  
Minimum Thickness ◽  
Lubrication Regimes ◽  
Minimum Film Thickness ◽  
Line Contacts ◽  
Good Agreement

This paper represents a solution for lubricated cylinders in line contact operating in the transition region between isoviscous-elastic and piezoviscous-elastic conditions. The computer solutions are used to generate a formula for the minimum film thickness. The approximate formula is compared with the existing formulae at the boundaries of the lubrication regimes where good agreement is obtained. Also, the influence of the starvation on pressure and film thickness is investigated.

scholarly journals Análise de um pavimento reforçado com geossintético a partir de resultados de ensaio em equipamento de grandes dimensões

TRANSPORTES ◽  
2011 ◽  
Vol 19 (3) ◽  
pp. 28
Author(s):  
Francis Massashi Kakuda ◽  
Alexandre Benetti Parreira ◽  
Glauco Tulio Pessa Fabbri
Keyword(s):  
Plastic Deformation ◽  
Numerical Modeling ◽  
Laboratory Tests ◽  
Resilient Modulus ◽  
Base Layer ◽  
Plastic Deformations ◽  
Elastic And Plastic Deformations ◽  
Back Calculation ◽  
Pavement Reinforcement ◽  
Elastic And Plastic Deformation

<p><strong>Resumo</strong>: O artigo analisa o beneficio do uso de uma geogrelha como reforço da camada de base de um pavimento. Seções do pavimento e subleito com dimensões próximas às reais submetidas a carregamentos cíclicos foram ensaiadas numa caixa metálica quadrada com lado de 1,5 m e altura de 1,2 m. Concluiu-se que a utilização da geogrelha proporciona a redução de deformações elásticas e permanentes, e que a eficiência do reforço posicionado na interface com o subleito é maior que a do reforço posicionado no horizonte médio da base. Foram ainda determinados os módulos de resiliência da base e do subleito a partir da retroanálise das bacias de deflexões obtidas nos ensaios. Finalmente, a análise numérica de um pavimento hipotético mostrou que a geogrelha pode proporcionar uma extensão expressiva na vida de fadiga do revestimento asfáltico.</p><p><strong>Palavras-chave</strong>: pavimentos reforçados com geosintéticos, geogrelha, ensaios de laboratório em verdadeira grandeza, deformações elásticas e plásticas sob carregamento cíclicos.</p><p><strong>Abstract</strong>: The article analyzes the benefits of the application of a geogrid as base layer pavement reinforcement. Cyclic loaded fullscale sections of pavement and subgrade were tested in a square metallic box with 1.5 m width and 1.2 m height. It was concluded that the geogrid reduces the elastic and plastic deformations and also that positioning the reinforcing at subgrade interface is more efficient than at base medium horizon. The base and subgrade resilient modulus were obtained by back calculation using the deflection basin results from the tests. Finally, a numerical modeling of a hypothetic pavement showed that the geogrid may conduct to an expressive increase of the bituminous surface life.</p><p><strong>Keywords</strong>: geosynthetic reforced pavement, geogrid, full-scale laboratory tests, elastic and plastic deformation under cyclic loadings.</p>

Microtwins of Transformation and their Effect on Excess Dislocation Density of FCC Deformed Material

2014 ◽  
Vol 1013 ◽  
pp. 72-76 ◽  
Author(s):  
Svetlana Kiseleva ◽  
Natal'ya Popova ◽  
Nina Koneva ◽  
Eduard Kozlov
Keyword(s):  
Plastic Deformation ◽  
Dislocation Density ◽  
Austenitic Steel ◽  
Internal Stresses ◽  
Plastic Deformations ◽  
Density Of Dislocations ◽  
Elastic And Plastic Deformations ◽  
Excess Density

The excess density of dislocations and internal stresses in local places of all polycrystal grain are determined. In work the methods of bending extinction contours observed by TEM is used to determine internal stresses of the deformed material. Thus depending on the deformation nature in each case components of elastic and plastic deformations or only plastic deformation was considered. The paper discusses the results of distribution of excess dislocation density and internal stresses within the grains of the austenitic steel deformed by tension (ε = 25%).

Numerical Analysis of Elastohydrodynamic Lubrication with Non-Newtonian Lubricant

2013 ◽  
Vol 388 ◽  
pp. 3-7
Author(s):  
Dedi Rosa Putra Cupu ◽  
Adli Bahari ◽  
Kahar Osman ◽  
Jamaluddin Md Sheriff
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Fluid Model ◽  
Contact Region ◽  
Roller Bearing ◽  
Elastohydrodynamic Lubrication ◽  
Physical Interaction ◽  
Infinite Length ◽  
Line Contact ◽  
Lubricated Contacts

Elastohydrodynamic lubrication is a form of hydrodynamic lubrication involving physical interaction between two contacting surfaces and liquid where elastic deformation of the contacting surfaces due to heavily loading applied will affect the elastohydrodynamic pressure and fluid film thickness significantly. In this paper, a line contact EHL is modeled through the cylinder contact to a flat surface to represent the application of roller bearing. This solution is limited to two dimensional line contact problem only, an infinite length of cylinder was used as physical modeling. The behavior of non-Newtonian fluid also was investigated using power law fluid model. Bearing speed is to be assumed in steady state and temperature is assumed constant. The bearing performance parameters such as pressure and film thickness of lubricated contacts are calculated using Newton-Raphson method.The results show that the peak pressure increases as the parameters such as velocity, load and material parameter were increases and the spike was found to shift to the center of roller. The film was almost flat at contact region and formed a dimple shape near the outlet flow. The value of pressure spike and minimum film thickness were smaller at lower speed and were increased during raising speed then the peak point was found to be shifted to center of roller.

A Biomimetic Approach to the Design of the Composite Bottle Cap and Deformation Analyses

2009 ◽  
Vol 2 ◽  
pp. 59-72
Author(s):  
Li Zhi Gu ◽  
Z. Zhang
Keyword(s):  
Plastic Deformation ◽  
Structural Feature ◽  
Thin Wall ◽  
Functional Requirements ◽  
Plastic Deformations ◽  
Pressing Force ◽  
Maximum Value ◽  
Elastic And Plastic Deformations ◽  
Biomimetic Approach

On the combination analog of the mussel ripple and leaf embrace, designed a new composite bottle cap consisting of the outer body, the inner lining washer, and the resin embrace, for multi-function, especially for better seal and ready open. According to the structural feature and the functional requirements of the cap, two fundamental components, the lining washer and the outer body, were abstracted into a plate and a cylinder with thin wall, respectively. Under the pressing force the elastic and plastic deformations of both were studied with Tresca’s yielding rule and the limitation of the plastic deformation was presented when the two components were assembled into a unit. For the production of this kind of bottle cap, the maximum value of the allowance press and the maximum pressing velocity were also provided.

Capillary forces drive buckling, plastic deformation, and break-up of 3D printed beams

Soft Matter ◽  
2021 ◽  
Vol 17 (14) ◽  
pp. 3886-3894
Author(s):  
Christopher S. O’Bryan ◽  
Alexandria Brady-Miné ◽  
Crystal J. Tessmann ◽  
Amanda M. Spotz ◽  
Thomas E. Angelini
Keyword(s):  
Plastic Deformation ◽  
Soft Materials ◽  
Capillary Forces ◽  
Plastic Deformations ◽  
Elastic And Plastic Deformations ◽  
3D Printed ◽  
Break Up

Capillary forces acting at the interfaces of soft materials lead to elastic and plastic deformations and instabilities that result in buckling, coiling, and break-up of 3D printed beams.

Sign in / Sign up

Export Citation Format

Share Document