scholarly journals KINEMATIC PAIRS: NOVEL KINDS AND SCIENTIFIC CLASSIFICATION

2021 ◽  
Vol 161 ◽  
pp. 38-74
Author(s):  
Stephen P. Radzevich
Keyword(s):  
Point Contact ◽  
Contact Geometry ◽  
Line Contact ◽  
General Sense ◽  
Gear Design ◽  
Functional Surfaces ◽  
Surface Contact ◽  
Scientific Classification

This paper deals with kinematic pairs in the most general sense, and, in particular, with those used in gear design. The paper begins with a brief overview of the earlier performed research in the field. Different kinds of kinematic pairs are distinguished, namely, point-contact kinematic pairs, line-contact kinematic pairs, and surface-to-surface-contact kinematic pairs. Contact geometry of functional surfaces in kinematic pairs is involved into the analysis aiming more in detail analysis of design, and the development of a scientific classification of kinematic pairs. A scientific classification of all possible kinds of kinematic pairs is developed. All known designs of kinematic pairs are covered by the classification. Moreover, kinematic pairs of all notknown yet designs are also covered by the classification. This means that the proposed classification of kinematic pairs possesses predictive properties.

MEDIATEXT IS A TOOL THAT DETERMINES THE QUALITY OF INFORMATION

2020 ◽  
Vol 6 (3) ◽  
pp. 158-164
Author(s):  
Navruza Yakhyayeva ◽  
Keyword(s):  
Functional Properties ◽  
Linguistic Features ◽  
Text Linguistics ◽  
Quality Of Information ◽  
The Creation ◽  
Linguistic Units ◽  
Scientific Classification

The quality and content of information in the article media text is based on scientific classification of linguistic features. The study of functional styles of speech, the identification of their linguistic signs, the discovery of the functional properties of linguistic units and their separation on the basis of linguistic facts is one of thetasks that modern linguistics is waiting for a solution. Text Linguistics, which deals with the creation, modeling of its structure and the study of the process of such activity, is of interest to journalists today as a science.

scholarly journals Optical Analysis of Ball Bearing Starvation

1971 ◽  
Vol 93 (3) ◽  
pp. 349-361 ◽  
Author(s):  
L. D. Wedeven ◽  
D. Evans ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
Ball Bearing ◽  
Point Contact ◽  
Experimental Measurements ◽  
Line Contact ◽  
Optical Analysis ◽  
Grease Lubrication ◽  
Theoretical Predictions ◽  
Pressure Stress ◽  
Starvation Conditions

Elastohydrodynamic oil film measurements for rolling point contact under starvation conditions are obtained using optical interferometry. The experimental measurements present a reasonably clear picture of the starvation phenomenon and are shown to agree with theoretical predictions. Starvation inhibits the generation of pressure and, therefore, reduces film thickness. It also causes the overall pressure, stress, and elastic deformation to become more Hertzian. Additional experiments using interferometry illustrate: the cavitation pattern, lubricant entrapment, grease lubrication, ball spin, and edge effects in line contact.

scholarly journals Microscopic and mechanical properties of undistributed and remoulded red clay from Guiyang, China

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanzhao Zhang ◽  
Shaoyun Pu ◽  
Rita Yi Man Li ◽  
Jing Zhang
Keyword(s):  
Point Contact ◽  
Morphological Properties ◽  
Line Contact ◽  
Red Clay ◽  
Undisturbed Soil ◽  
Pore Area ◽  
Distribution Index ◽  
Curved Slice ◽  
Clay Aggregates ◽  
Scanning Electron

Abstract Unconsolidated-undrained (UU) tests were conducted to investigate the mechanical and morphological properties of undisturbed and remoulded red clay, with the microscopic characteristics determined by scanning electron microscopy (SEM). The microanalysis showed that the red clay aggregate was granular, curved-slice and thin layered and flower-shaped ellipsoid, with X and Y-type cracks and pores in the undisturbed red clay. Moreover, the contact modes of red clay aggregates were point contact, line contact, surface contact and mosaic contact. In addition, the main microstructure red clay was flocculation, honeycomb and pseudosphere structures. The pores in undisturbed soil were arranged in one direction, with no obvious directionality in remoulded red clay. The pore area, perimeter and maximum length of undisturbed red clay were smaller than those of remoulded red clay, with a larger probability entropy, probability distribution index and fractal dimension of pore distribution of undisturbed red clay than remoulded red clay. UU tests showed that the shear strength of undisturbed red clay was higher than that of remoulded red clay.

scholarly journals A SCIENTIFIC CLASSIFICATION OF VOLATILITY MODELS

2010 ◽  
Vol 24 (1) ◽  
pp. 192-195
Author(s):  
Massimiliano Caporin ◽  
Michael McAleer
Keyword(s):  
Volatility Models ◽  
Scientific Classification

Restraint Analysis of Fixtures Which Rely on Surface Contact

1994 ◽  
Vol 116 (2) ◽  
pp. 207-215 ◽  
Author(s):  
E. C. DeMeter
Keyword(s):  
Point Contact ◽  
Linear Program ◽  
Static Equilibrium ◽  
Frictional Surface ◽  
Equilibrium Constraints ◽  
Modular Fixture ◽  
Surface Contact ◽  
Planar Contact

Total restraint analysis is used to evaluate the ability of a machining fixture to restrain workpiece motion. Thus far models have been limited to point contact and frictionless planar contact. This paper shows how to apply restraint analysis to a fixture which relies on frictionless or frictional surface contact. It presents models of the wrench systems defined by frictionless and frictional planar, spherical, and cylindrical contact as well as hard point contact. These models are applicable to the restraint analysis of other work holding devices such as gripper and assembly fixtures. In addition, they are the basis for other types of fixture analysis. This paper also presents a linear program which uses static equilibrium constraints to directly prove the existence of total restraint. Both the models and the linear program are applied to the analysis of a modular fixture.

A Three-Dimensional Model of Line-Contact Elastohydrodynamic Lubrication for Heterogeneous Materials with Inclusions

2016 ◽  
Vol 08 (02) ◽  
pp. 1650014 ◽  
Author(s):  
Kun Zhou ◽  
Qingbing Dong
Keyword(s):  
Film Thickness ◽  
Half Space ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Lubricant Film ◽  
Line Contact ◽  
Lubricant Film Thickness ◽  
Equivalent Inclusion Method ◽  
Surface Contact

This paper develops a three-dimensional (3D) model for a heterogeneous half-space with inclusions distributed periodically beneath its surface subject to elastohydrodynamic lubrication (EHL) line-contact applied by a cylindrical loading body. The model takes into account the interactions between the loading body, the fluid lubricant and the heterogeneous half-space. In the absence of subsurface inclusions, the surface contact pressure distribution, the half-space surface deformation and the lubricant film thickness profile are obtained through solving a unified Reynolds equation system. The inclusions are homogenized according to Eshelby’s equivalent inclusion method (EIM) with unknown eigenstrains to be determined. The disturbed half-space surface deformations induced by the subsurface inclusions or eigenstrains are iteratively introduced into the lubricant film thickness until the surface deformation finally converges. Both time-independent smooth surface contact and time-dependent rough surface contact are considered for the lubricated contact problem.

Analysis of Microelastohydrodynamic and Mixed Lubrication Effects in Gear Tooth Contacts

2003 ◽  
Author(s):  
M. J. A. Holmes ◽  
H. P. Evans ◽  
R. W. Snidle
Keyword(s):  
Contact Area ◽  
Transient Analysis ◽  
Gear Tooth ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Contact Analysis ◽  
Line Contact ◽  
Hydrodynamic Equations ◽  
Analysis Technique ◽  
Film Thinning

The paper presents results obtained using a transient analysis technique for point contact elastohydrodynamic lubrication (EHL) problems based on a formulation that couples the elastic and hydrodynamic equations. Results are presented for transverse ground surfaces in elliptical point contact that show severe film thinning at the transverse limits of the contact area. This thinning is caused by transverse leakage of the lubricant from the contact in the remaining deep valley features. A comparison is also made between the point contact results on the entrainment centre line and the equivalent line contact analysis.

Rough Surface Contact of Curved Conformal Surfaces: An Application to Rotor–Stator Rub

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Philip Varney ◽  
Itzhak Green
Keyword(s):  
Rough Surface ◽  
Contact Force ◽  
Contact Stiffness ◽  
Point Contact ◽  
Contact Model ◽  
Industrial Society ◽  
Real Surface ◽  
Linear Elastic ◽  
Surface Contact ◽  
Rough Surface Contact

Rotating machines and associated triboelements are ubiquitous in industrial society, playing a central role in power generation, transportation, and manufacturing. Unfortunately, these systems are susceptible to undesirable contact (i.e., rub) between the rotor and stator, which is both costly and dangerous. These adverse effects can be alleviated by properly applying accurate real-time diagnostics. The first step toward accurate diagnostics is developing rotor–stator rub models which appropriately emulate reality. Previous rotor–stator rub models disavow the contact physics by reducing the problem to a single esoteric linear contact stiffness occurring only at the point of maximum rotor radial deflection. Further, the contact stiffness is typically chosen arbitrarily, and as such provides no additional insight into the contacting surfaces. Here, a novel rotor–stator rub model is developed by treating the strongly conformal curved surfaces according to their actual nature: a collection of stochastically distributed asperities. Such an approach is advantageous in that it relies on real surface measurements to quantify the contact force rather than a heuristic choice of linear contact stiffness. Specifically, the elastoplastic Jackson–Green (JG) rough surface contact model is used to obtain the quasistatic contact force versus rotor radial deflection; differences and similarities in contact force between the linear elastic contact model (LECM) and JG model are discussed. Furthermore, the linear elastic model's point contact assumption is assessed and found to be inaccurate for systems with small clearances. Finally, to aid in computational efficiency in future rotordynamic simulation, a simple exponential curve fit is proposed to approximate the JG force–displacement relationship.

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