A New Method for the Analysis of Deformation and Load in a Ball Bearing With Variable Contact Angle

1999 ◽  
Vol 123 (2) ◽  
pp. 304-312 ◽  
Author(s):  
Neng Tung Liao ◽  
Jen Fin Lin
Keyword(s):  
Contact Angle ◽  
Elastic Deformation ◽  
Newton Method ◽  
Contact Surface ◽  
Ball Bearing ◽  
Three Dimensional ◽  
Position Angle ◽  
New Method ◽  
Mechanism Analysis ◽  
Acting Force

The contact angle of a ball in a ball bearing is conventionally assumed to be a constant value in the mechanism analysis; in reality, this is not true. This assumption is made for the purpose of simplifying calculations, but the real elastic deformation produced at the position of each ball due to the acting force varying with the contact angle is unable to be considered. This study tries to establish a simple, three-dimensional expression for the elastic deformation at different position angles in terms of the geometry of the contact surface at the inner and outer races. Simply using the Newton method when the bearing deformations in the radial and axial directions are available can solve the contact angle as a function of position angle. Several characteristics arising from the variable contact angle will be discussed.

Pitch bearing/raceway fretting: Influence of contact angle

2018 ◽  
Vol 233 (5) ◽  
pp. 1734-1749 ◽  
Author(s):  
Peiyu He ◽  
Rongjing Hong ◽  
Hua Wang ◽  
Cheng Lu
Keyword(s):  
Contact Angle ◽  
Maximum Stress ◽  
Ball Bearing ◽  
Three Dimensional ◽  
Contact Angles ◽  
Critical Parameters ◽  
Relative Slip ◽  
Contact State ◽  
Pitch Bearing ◽  
Bearing Raceway

In this paper, a three-dimensional numerical simulation (using ABAQUS) of the radial and tangential wear between a ball bearing and a raceway is presented. The aim was to study the influence of the contact angle between ball and raceway on the fretting. A range of contact angles was studied with critical parameters such as contact stress, relative slip, plastic deformation, and contact state. The model was validated against experimental data. The results show that with an increase in the contact angle, the area of maximum stress increases, the bearing capacity of the raceway decreases, and the maximum radial stress moves from the sub-surface to the raceway surface. The raceway surface is shown to be prone to peeling and wear, which reduces the service life of the raceway.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

scholarly journals A New Method to Evaluate Trueness and Precision of Digital and Conventional Impression Techniques for Complete Dental Arch

2021 ◽  
Vol 11 (10) ◽  
pp. 4612
Author(s):  
KweonSoo Seo ◽  
Sunjai Kim
Keyword(s):  
Intraclass Correlation ◽  
Three Dimensional ◽  
New Method ◽  
Digital Impression ◽  
Dental Arch ◽  
Digital Models ◽  
Digital Impressions ◽  
Measuring Machine ◽  
Master Model ◽  
Conventional Impression

Purpose: The aim of this study was to present a new method to analyze the three-dimensional accuracy of complete-arch dental impressions and verify the reliability of the method. Additionally, the accuracies of conventional and intraoral digital impressions were compared using the new method. Methods: A master model was fabricated using 14 milled polyetheretherketone cylinders and a maxillary acrylic model. Each cylinder was positioned and named according to its corresponding tooth position. Twenty-five definitive stone casts were fabricated using conventional impressions of the master model. An intraoral scanner was used to scan the master model 25 times to fabricate 25 digital models. A coordinate measuring machine was used to physically probe each cylinder in the master model and definitive casts. An inspection software was used to probe cylinders of digital models. A three-dimensional part coordinate system was defined and used to compute the centroid coordinate of each cylinder. Intraclass correlation coefficient (ICC) was evaluated to examine the reliability of the new method. Independent two sample t-test was performed to compare the trueness and precision of conventional and intraoral digital impressions (α = 0.05). Results: ICC results showed that, the new method had almost perfect reliability for the measurements of the master model, conventional and digital impression. Conventional impression showed more accurate absolute trueness and precision than intraoral digital impression for most of the tooth positions (p < 0.05). Conclusions: The new method was reliable to analyze the three-dimensional deviation of complete-arch impressions. Conventional impression was still more accurate than digital intraoral impression for complete arches.

A new method for volumetric measurement of the normal female cervix by three‐dimensional transvaginal ultrasound

2021 ◽  
Author(s):  
Matija Prka ◽  
Albert Despot ◽  
Alemka Brnčić Fischer ◽  
Herman Haller ◽  
Ana Tikvica Luetić ◽  
...  
Keyword(s):  
Transvaginal Ultrasound ◽  
Three Dimensional ◽  
New Method ◽  
Normal Female ◽  
Volumetric Measurement

scholarly journals Three-dimensional analysis of the root canal preparation with Reciproc Blue®, WaveOne Gold® and XP EndoShaper®: a new method in vivo

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Javier Caviedes-Bucheli ◽  
Nestor Rios-Osorio ◽  
Diana Usme ◽  
Cristian Jimenez ◽  
Adriana Pinzon ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Root Canal ◽  
Paired Comparison ◽  
Three Dimensional ◽  
New Method ◽  
Root Canal Preparation ◽  
Paired Data ◽  
Before And After ◽  
Student’S T

Abstract Background The purpose of this study was to evaluate the changes in canal volume after root canal preparation in vivo with 3 different single-file techniques (Reciproc-Blue®, WaveOne-Gold® and XP-EndoShaper®), with a new method using CBCT and 3D reconstruction. Methods In this prospective study, thirty human lower premolars from healthy patients were used, in which extraction was indicated for orthodontic reasons. All the teeth used were caries- and restoration-free with complete root development, without signs of periodontal disease or traumatic occlusion, and with only one straight canal (up to 25º curvature). Teeth were randomly divided into three different groups: Reciproc-Blue, WaveOne-Gold and XP-EndoShaper. CBCT scans before root canal preparation were used to create a 3D reconstruction with RHINOCEROS 5.0 software to assess the initial canal volume, and then compared with 3D reconstructions after canal preparation to measure the increase in canal volume. Student’s t test for paired data were used to determine statistically significant differences between the before and after canal volumes. Anova test was used to determine statistically significant differences in the percentage of canal volume increase between the groups and Tukey's post-hoc test were used to paired comparison. Results Reciproc-Blue showed the higher increase in canal volume, followed by WaveOne-Gold and XP-EndoShaper (p = 0.003). XP-EndoShaper did not show a statistically significant increase in canal volume after root canal preparation (p = 0.06). Conclusion With this model, Reciproc-Blue showed higher increase in root canal volume, followed by WaveOne-Gold, while XP-EndoShaper did not significantly increase root canal volume during preparation.

Measurement of the Interfacial Stresses in Rolling Using the Elastic Deformation of the Roll

1987 ◽  
Vol 109 (4) ◽  
pp. 362-369 ◽  
Author(s):  
D. J. Meierhofer ◽  
K. A. Stelson
Keyword(s):  
Elastic Deformation ◽  
Normal Pressure ◽  
New Method ◽  
Frictional Stress ◽  
Stress Distributions ◽  
Strain Gages ◽  
Experimental Rolling ◽  
Mechanical Isolation ◽  
Roll Gap ◽  
Future Work

A new method to measure the frictional stresses and normal pressure in the roll gap during cold rolling, and experimental verification of this new method, are presented. The method overcomes many of the shortcomings of pin-type sensors. The elastic deformation of the roll itself is measured with strain gages, and is used to calculate the stresses between the sheet and the roll. Since no modification of the roll is necessary, the deformation process is undisturbed by the measurement. Mechanical isolation of the sensor is unnecessary. The mathematical procedure used to calculate the normal pressure and frictional stresses from the measured strains explicitly acknowledges that these strains are the result of the entire distribution of pressures and shears in the roll gap. An experimental rolling mill was constructed to verify the proposed method. Lead was rolled, and the resulting pressure and frictional stress distributions in the roll gap were measured. Several features of these distributions are in agreement with measurements made by various investigators using other techniques, thereby confirming the usefulness of the new method. Future work is proposed to increase the accuracy with which the roll gap stresses may be measured.

New method of holographic three-dimensional tracking of living cells exploiting their morphological properties

2013 ◽  
Author(s):  
Pasquale Memmolo ◽  
Maria Iannone ◽  
Maurizio Ventre ◽  
Paolo Antonio Netti ◽  
Andrea Finizio ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Living Cells ◽  
New Method ◽  
Morphological Properties

Effect of Steady Rest in Cylindrical Traverse Grinding of Slender Workpiece

2020 ◽  
Author(s):  
Hidetaka Fujii ◽  
Takashi Onishi ◽  
Chinhu Lin ◽  
Moriaki Sakakura ◽  
Kazuhito Ohashi
Keyword(s):  
Elastic Deformation ◽  
Contact Point ◽  
Traverse Speed ◽  
Grinding Force ◽  
New Method ◽  
Beam Model ◽  
Shape Error ◽  
Form Error ◽  
Low Stiffness ◽  
Traverse Grinding

Abstract In the case of traverse grinding of a slender workpiece, the ground workpiece is easily deformed by the normal grinding force due to its low stiffness. To reduce the form error caused by the elastic deformation of the workpiece, a steady rest is widely used. Generally, a steady rest is set to push the ground area of the workpiece. However, the stepped shape error is generated at the contact point where a steady rest pushed the workpiece because the pushing force of a steady rest is decreased after the material of the contact point is removed. In this study, to reduce the stepped shape error of the ground workpiece, we proposed a new method to set a steady rest. In this method, the steady rest was set to push the area where was not ground. In addition, the traverse speed of the workpiece was adjusted to keep the elastic deformation of the workpiece constant. The suitable method to control the traverse speed was estimated by using a beam model that could simulate the elastic deformation of the workpiece during the grinding process. It was confirmed that the new method could improve the form accuracy of a slender workpiece through grinding experiments.

Sign in / Sign up

Export Citation Format

Share Document