Curvature Analysis of Surfaces in Higher Pair Contact—Part 1: An Analytical Investigation

1976 ◽  
Vol 98 (2) ◽  
pp. 397-402 ◽  
Author(s):  
S. G. Dhande ◽  
J. Chakraborty
Keyword(s):  
Velocity Ratio ◽  
Analytical Investigation ◽  
Principal Curvatures ◽  
Curvature Analysis ◽  
Contact Surfaces ◽  
Contact Part

In this paper, the analytical investigation is done to evaluate the normal and principal curvatures of contacting surfaces in higher pair contact. The velocity ratio of the members connected with the higher-pair-contact surfaces is assumed to be variable. The principal curvatures of the generated or driven surface are expressed in terms of those of the generating or driving surface.

Curvature Analysis of Surfaces in Higher Pair Contact—Part 2: Application to Spatial Cam Mechanisms

1976 ◽  
Vol 98 (2) ◽  
pp. 403-409 ◽  
Author(s):  
S. G. Dhande ◽  
J. Chakraborty
Keyword(s):  
Three Dimensional ◽  
Principal Curvatures ◽  
Numerical Example ◽  
Curvature Analysis ◽  
Contact Part

In this paper curvature analysis is performed for different three-dimensional cam mechanisms. In every case the expressions for principal curvatures of the cam surface are given in closed forms for ready use. A numerical example is given to show the usefulness of the proposed procedure.

scholarly journals Multiscale 3D Curvature Analysis of Processed Surface Textures of Aluminum Alloy 6061 T6

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 257 ◽  
Author(s):  
Tomasz Bartkowiak ◽  
Christopher A. Brown
Keyword(s):  
Principal Curvatures ◽  
Surface Textures ◽  
Curvature Analysis ◽  
Mass Finishing ◽  
Dependent Behavior ◽  
Surface Topographies ◽  
Laser Confocal Microscope ◽  
Curvature Tensors ◽  
Alloy 6061

The objectives of this paper are to demonstrate the viability, and to validate, in part, a multiscale method for calculating curvature tensors on measured surface topographies with two different methods of specifying the scale. The curvature tensors are calculated as functions of scale, i.e., size, and position from a regular, orthogonal array of measured heights. Multiscale characterization of curvature is important because, like slope and area, it changes with the scale of observation, or calculation, on irregular surfaces. Curvatures can be indicative of the topographically dependent behavior of a surface and, in turn, curvatures are influenced by the processing and use of the surface. Curvatures of surface topographies have not been well- characterized yet. Curvature has been used for calculations in contact mechanics and for the evaluation of cutting edges. Manufactured surfaces are studied for further validation of the calculation method because they provide certain expectations for curvatures, which depend on scale and the degree of curvature. To study a range of curvatures on manufactured surfaces, square edges are machined and honed, then rounded progressively by mass finishing; additionally, a set of surfaces was made by turning with different feeds. Topographic measurements are made with a scanning laser confocal microscope. The calculations use vectors, normal to the measured surface, which are calculated first, then the eigenvalue problem is solved for the curvature tensor. Plots of principal curvatures as a function of position and scale are presented. Statistical analyses show expected interactions between curvature and these manufacturing processes.

The Generation of Contact Surfaces of Indexing Cam Mechanisms: A Unified Approach

1990 ◽  
Author(s):  
M. A. Gonzalez-Palacios ◽  
J. Angeles ◽  
Ch. Cai
Keyword(s):  
Angular Velocity ◽  
Velocity Ratio ◽  
Rigid Bodies ◽  
Ruled Surfaces ◽  
Time Varying ◽  
Unified Approach ◽  
Unified Framework ◽  
Spatial Mechanisms ◽  
Contact Surfaces

Abstract In this paper the ruled surfaces of two rigid bodies that are in contact while moving with a prescribed time-varying angular-velocity ratio are generated. These are then used as the contact surfaces of indexing cam mechanisms. In this way, planar, spherical and spatial mechanisms can be synthesized in a unified framework. The approach is illustrated with various examples.

Fretting Wear Characteristics of Tube-Support Components for a Steam Generator in Elevated Temperature

2005 ◽  
Author(s):  
Sung-Hoon Jeong ◽  
Young-Ze Lee
Keyword(s):  
High Pressure ◽  
Wear Mechanisms ◽  
Nuclear Power ◽  
Fretting Wear ◽  
Wear Volume ◽  
Steam Generators ◽  
Flow Induced Vibration ◽  
Wear Characteristics ◽  
Contact Surfaces ◽  
Contact Part

Tubes in nuclear steam generators are held up by supports because the tubes are long and slender. Fluid of high-pressure and high-temperature flows in the tubes and the flows cause oscillating motions between tubes and supports. This is called FIV (flow induced vibration) which cause fretting wear in contact part of tube-support. The fretting wear of tube-support can threaten the safety of nuclear power plant. Therefore, a research about the fretting wear characteristics of tube-support is required. This work is focused on investigations of fretting wear characteristics and wear mechanisms of tube-support. Results are that the wear rate of tube is proportional to that of support and as water temperature increases the wear volume of tube-support decreases because the oxidation rate decreases due to lack of the oxygen concentration in contact surfaces. Also, the wear mechanisms of tube-support are abrasive and oxidational wear.

Wear Characteristics of Tube-Support Components for a Nuclear Steam Generator under Fretting Conditions

2007 ◽  
Vol 120 ◽  
pp. 181-186 ◽  
Author(s):  
Sung Hoon Jeong ◽  
Young Ze Lee
Keyword(s):  
Wear Mechanisms ◽  
Nuclear Power ◽  
Fluid Flows ◽  
Fretting Wear ◽  
Wear Volume ◽  
Steam Generators ◽  
Flow Induced Vibration ◽  
Wear Characteristics ◽  
Contact Surfaces ◽  
Contact Part

Tubes in nuclear steam generators are held up by supports because the tubes are long and slender. Fluid flows of high-pressure and high-temperature flows in the tubes cause oscillating motions between tubes and supports. This is called as FIV (flow induced vibration) which cause fretting wear in contact part of tube-support. The reduction of tube thickness due to fretting wear of tube-support can threaten the safety of nuclear power plant. Therefore, a research on the fretting wear characteristics of tube-support is required. This work is focused on investigations of fretting wear characteristics and wear mechanisms of tube-support. Results show that the wear rate of tube is proportional to that of support and that with increasing the water temperature the wear volume of tube-support decreases because the oxidation rate decreases due to reduction of the oxygen concentration in contact surfaces. Also, the wear mechanisms of tube-support are abrasive and oxidational wear.

scholarly journals Multi-scale curvature tensor analysis of machined surfaces

2016 ◽  
Vol 36 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Tomasz Bartkowiak ◽  
Christopher Brown
Keyword(s):  
Surface Characterization ◽  
Multiple Scales ◽  
Geometric Analysis ◽  
Principal Curvatures ◽  
Multi Scale ◽  
Curvature Analysis ◽  
Dependent Behavior ◽  
Surface Topographies ◽  
Laser Confocal Microscope ◽  
Conventional Machining

Abstract This paper demonstrates the use of multi-scale curvature analysis, an areal new surface characterization technique for better understanding topographies, for analyzing surfaces created by conventional machining and grinding. Curvature, like slope and area, changes with scale of observation, or calculation, on irregular surfaces, therefore it can be used for multi-scale geometric analysis. Curvatures on a surface should be indicative of topographically dependent behavior of a surface and curvatures are, in turn, influenced by the processing and use of the surface. Curvatures have not been well characterized previously. Curvature has been used for calculations in contact mechanics and for the evaluation of cutting edges. In the current work two parts were machined and then one of them was ground. The surface topographies were measured with a scanning laser confocal microscope. Plots of curvatures as a function of position and scale are presented, and the means and standard deviations of principal curvatures are plotted as a function of scale. Statistical analyses show the relations between curvature and these two manufacturing processes at multiple scales.

The Generation of Contact Surfaces of Indexing Cam Mechanisms—A Unified Approach

1994 ◽  
Vol 116 (2) ◽  
pp. 369-374 ◽  
Author(s):  
M. A. Gonza´lez-Palacios ◽  
J. Angeles
Keyword(s):  
Angular Velocity ◽  
Velocity Ratio ◽  
Rigid Bodies ◽  
Ruled Surfaces ◽  
Time Varying ◽  
Unified Approach ◽  
Unified Framework ◽  
Pressure Angle ◽  
Spatial Mechanisms ◽  
Contact Surfaces

In this paper the ruled surfaces of two rigid bodies that are in contact while moving with a prescribed time-varying angular-velocity ratio are generated. These are then used as the contact surfaces of indexing cam mechanisms. In this way, planar, spherical, and spatial mechanisms are synthesized in a unified framework, the pressure angle, for all these cases, being analyzed. The approach is illustrated with various examples.

Mathematical model of curvature analysis for conjugate surfaces with generalized motion in three dimensions

2001 ◽  
Vol 215 (4) ◽  
pp. 487-502 ◽  
Author(s):  
C-K Chen ◽  
S-T Chiou ◽  
Z-H Fong ◽  
C-K Lee ◽  
C-H Chen
Keyword(s):  
Mathematical Model ◽  
Differential Geometry ◽  
Three Dimensions ◽  
Cnc Machine ◽  
Principal Curvatures ◽  
Tooth Contact Analysis ◽  
Curvature Analysis ◽  
Computer Numerically Controlled ◽  
General Mathematical Model ◽  
Conjugate Surfaces

A general mathematical model is proposed to determine the direct relations between the principal curvatures and directions of two conjugate surfaces in continuous tangency along a line at every instant. Without any assumption regarding the motion of mating surfaces, this model, created on the basis of kinematics, the theory of gearing and differential geometry, is especially suitable for calculating the curvatures of a surface generated on a computer numerically controlled (CNC) machine with surface modifications by non-constant-speed supplemental correcting motions. The model has simplified dramatically the calculation of curvatures by comparison with the differential geometry approach. The principal curvatures of a generated surface and dimensions of contact ellipses can be obtained by the model without the need for complicated equations of the generated surface. For verification of the model, a helical gear set comprising a gear with involuted teeth and a pinion with modified circular arc teeth is investigated. The tooth contact analysis (TCA) technique is also applied to study the shift of bearing contacts and dimensions of contact ellipses under three different kinds of generation setting.

Curvature Analysis Method for Ship-Hull Plate Forming

2005 ◽  
Vol 21 (02) ◽  
pp. 65-72
Author(s):  
Zhang Xuebiao ◽  
Ji Zhuoshang ◽  
Liu Yujun
Keyword(s):  
Principal Curvature ◽  
Ship Hull ◽  
Analysis Method ◽  
Principal Curvatures ◽  
Line Heating ◽  
Bending Angle ◽  
Curvature Analysis ◽  
Curvature Distribution ◽  
Ship Hull Plate ◽  
Adjustment Of Parameters

Ship-hull plate forming by line heating requires hard and skillful labor. Initially, the plate is curved in one direction by rolling. Then, the curved plate is transported to the line-heating workshop to obtain the required shrinkage. However, this two-step forming leads to a series of problems. This paper presents a method to change the two-step forming into line-heating forming by using curvature analysis. The principal curvatures of the formed plate can be calculated directly from the offset data. The principal curvature distribution provides information on the deformation distribution and the heating lines. Heating along a line will result in a uniform bending angular deformation. A numerical method to determine the heating lines to produce the required bending angle is presented. This kind of heating line does not require adjustment of parameters in line heating. It would benefit temperature control and facilitate plate forming automatically.

Analytical Investigation of Commercial Geranium Oils from Pelargonium graveolens L'Hér

Planta Medica ◽  
2012 ◽  
Vol 78 (05) ◽  
Author(s):  
M Wang ◽  
A Chittiboyina ◽  
B Avula ◽  
J Zhao ◽  
N Tabanca ◽  
...  
Keyword(s):  
Analytical Investigation ◽  
Pelargonium Graveolens
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