scholarly journals The axisymmetric stress analysis of double contact problem for functionally graded materials layer with arbitrary graded materials properties

2016 ◽  
Vol 96 ◽  
pp. 229-239 ◽  
Author(s):  
Tie-Jun Liu ◽  
Chuanzeng Zhang ◽  
Yue-Sheng Wang ◽  
Yong-Ming Xing
Keyword(s):  
Contact Problem ◽  
Stress Analysis ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Axisymmetric Stress ◽  
Graded Materials ◽  
Materials Properties

Stress analysis of rotating nano-disks of variable thickness made of functionally graded materials

2016 ◽  
Vol 109 ◽  
pp. 29-53 ◽  
Author(s):  
Mohammad Hosseini ◽  
Mohammad Shishesaz ◽  
Khosro Naderan Tahan ◽  
Amin Hadi
Keyword(s):  
Stress Analysis ◽  
Functionally Graded Materials ◽  
Variable Thickness ◽  
Functionally Graded ◽  
Graded Materials

Lubricated point heavily loaded contacts of functionally graded materials. Part 1. Dry contacts

2017 ◽  
Vol 23 (7) ◽  
pp. 1061-1080 ◽  
Author(s):  
Ilya I Kudish ◽  
Sergey S Volkov ◽  
Andrey S Vasiliev ◽  
Sergey M Aizikovich
Keyword(s):  
Contact Problem ◽  
Film Thickness ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Elastic Materials ◽  
Graded Materials ◽  
Lubrication Film ◽  
Lubricated Contacts ◽  
Dry Contact ◽  
Lubricated Contact

Over the last couple decades coatings attract more and more attention in practical applications. The present study addresses a question which is not well studied: how coated surfaces behave in lubricated contacts? In other words, this is a study of the effectiveness of functionally graded materials in heavily loaded point elastohydrodynamically lubricated contacts with straight lubricant entrainment. As a part of the study, some criteria of coating effectiveness are introduced and discussed. More specifically, the behavior of main parameters such as the lubrication film thickness and the frictional force in point heavily loaded lubricated contacts of functionally graded elastic materials are considered. The problem is studied based on the method of matched asymptotic expansions which allows us to split the problem into two separate problems: a dry contact problems for functionally graded elastic materials and an elastohydrodynamically lubricated problem for functionally graded materials. The elastohydrodynamically lubricated problem uses as input data not only the operational and physical parameters of the materials and lubricant but also the asymptotic behavior of the dry contact problem solution near the contact boundaries. Therefore, a sequence of two problems must be solved: the dry contact problems for functionally graded elastic materials and the elastohydrodynamically lubricated problem for functionally graded materials. Similar methods have been used for the analysis of an elastohydrodynamically lubricated problem for heavily loaded line contacts of functionally graded materials. The dry contact problem will be analyzed in Part 1 of the paper based on a semi-analytical bilateral method which produces correct asymptotic solutions for thin and thick coatings. The analytical expressions for contact pressure are obtained and analyzed for various combinations of coating thicknesses and elastic properties. The elastohydrodynamically lubricated problem will be considered in Part 2 of the paper based on the method of matched asymptotic expansions. In the analysis of the elastohydrodynamically lubricated problem, as in the case of homogeneous contact materials, it is shown that the whole contact region can be subdivided into three subregions: the central one which is adjacent to the other two regions occupied by the ends of the zones. The central region can be subdivided into the Hertzian region and then adjacent to it inlet and exit zones which, in turn, are adjacent to the inlet and exit boundaries of the contact, respectively. In the Hertzian region the elastohydrodynamically lubricated problem solution is very close to the solution of the corresponding dry (i.e. non-lubricated) contact problem for functionally graded elastic materials which have been analyzed. In the central region in the inlet and exit zones of a heavily loaded point elastohydrodynamically lubricated contact, the elastohydrodynamically lubricated problem for functionally graded elastic materials using certain scaling transforms can be reduced to asymptotically valid equations identical to the ones obtained in the inlet and exit zones of heavily loaded line elastohydrodynamically lubricated contacts for homogeneous elastic materials. Therefore, many of the well known properties of heavily loaded line elastohydrodynamically lubricated contacts for homogeneous elastic materials are also valid for heavily loaded point elastohydrodynamically lubricated contacts for functionally graded elastic materials. These asymptotically valid equations can be analyzed and numerically solved based on stable methods using a specific regularization approach, which were developed for lubricated line contacts. Also, this asymptotic analysis leads to an easy analytical derivation of formulas for the lubrication film thickness which take into account the inhomogeneity of the elastic materials. As a result of this analysis, some criteria for lubrication film thickness increase and friction force reduction are proposed. These criteria depend on lubricant properties as well as the properties of functionally graded elastic materials involved in lubricated contacts. Such a sequential solution of the elastohydrodynamically lubricated problem for functionally graded materials makes it perfectly clear what the dependence is of elastohydrodynamically lubricated contact parameters on the solid material (including the coating) and lubricant properties.

The Identification Analysis for Macro Distributions Curves of Functionally Graded Materials Properties Based on Materials Components

2011 ◽  
Vol 228-229 ◽  
pp. 50-54
Author(s):  
Chao Feng Ge
Keyword(s):  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Experimental Conditions ◽  
Graded Materials ◽  
Materials Properties ◽  
Dynamic Analyses ◽  
Identification Technique ◽  
Identification Analysis ◽  
The Given

There are much complex internal microstructures of functionally graded materials, and the mechanical parameters of functionally graded materials structures varied with the space coordinates. Therefore, it is generally difficult to measure point by point macro distributions curves of functionally graded materials properties based on available experimental conditions. The prerequisite for various analyses of the functionally graded materials structures is the determination of macro distributions curves of materials properties parameters. In practice, only the spatial distributions of different material components can be controlled in the course of materials production. Therefore, the functionally graded distributions curves need inversing and identifying by the materials components. In the present paper, the inversion and identification technique was put forward based on the positive static and dynamic analyses by the microelement method, which was applied to do the scale-span analyses for macro responses of functionally graded materials structures based on the given materials components distributions in production.

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