scholarly journals Research on Sealing Properties and its Influence Factors of Spherical Mechanical Seal Based on ANSYS

2016 ◽  
Vol 10 (1) ◽  
pp. 160-172
Author(s):  
Xuhui Zhou ◽  
Zhenglin Liu ◽  
Li Zou ◽  
Xingxin Liang ◽  
Huanjie Wang ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Thermal Structure ◽  
Contact Region ◽  
Engineering Application ◽  
Underwater Vehicles ◽  
Outer Diameter ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
Study Results ◽  
Maximum Contact

When a marine stern shaft is bent with shafting misalignment and stern bearing wear factors, etc., the sealing properties of a plane mechanical seal is declined with the increase of both contact pressure and temperature of sealing surface, so a spherical mechanical seal which can automatically adjust the contact state of sealing surfaces is proposed to replace the plane mechanical seal in order to solve the aforementioned problems. The sealing properties of a spherical mechanical seal is directly influenced by the sealing structure size such as sealing spherical radius, the distance between stator and rotary ring seats, inner and outer diameters of stator ring. The thermal-structure coupling model of the spherical mechanical seal in underwater vehicles is built with ANSYS finite element method, and the influence of structure size on the sealing performances of the spherical mechanical seal is discussed. The study results show that as spherical radius is increased, the contact region of spherical sealing surfaces is decreased and the opening region is expanded, and the highest temperature and maximum contact pressure on the spherical sealing surfaces are raised. As inner or outer diameter of stator ring is increased, the maximum contact pressure of the former is raised, and one of the latter is declined, but the highest temperatures of both on sealing surfaces are enhanced linearly. When the distance between static and rotary ring seats is increased, the highest temperature of sealing surface and maximum contact pressure are increased in a nonlinear way. These conclusions are of important theoretical significance and engineering application value for the structure optimization of spherical mechanical seals in vessels, particularly underwater vehicles.

Analysis of contact mechanics in McKee-Farrar metal-on-metal hip implants

2003 ◽  
Vol 217 (5) ◽  
pp. 333-340 ◽  
Author(s):  
A Yew ◽  
M Jagatia ◽  
H Ensaff ◽  
Z M Jin
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Region ◽  
Radial Clearance ◽  
Geometrical Parameters ◽  
Contact Pressure Distribution ◽  
Acetabular Cup ◽  
Metal On Metal ◽  
Half Angle ◽  
Maximum Contact

Contact mechanics analysis for a typical McKee-Farrar metal-on-metal hip implant was carried out in this study. The finite element method was used to predict the contact area and the contact pressure distribution at the bearing surfaces. The study investigated the effects of the cement and underlying bone, the geometrical parameters such as the radial clearance between the acetabular cup and the femoral head, and the acetabular cup thickness, as well as other geometrical features on the acetabular cup such as lip and studs. For all the cases considered, the predicted contact pressure distribution was found to be significantly different from that based upon the classical Hertz contact theory, with the maximum value being away from the centre of the contact region. The lip on the cup was found to have a negligible effect on the predicted contact pressure distribution. The presence of the studs on the outside of the cup caused a significant increase in the local contact pressure distribution, and a slight decrease in the contact region. Reasonably good agreement of the predicted contact pressure distribution was found between a three-dimensional anatomical model and a simple two-dimensional axisymmetric model. The interfacial boundary condition between the acetabular cup and the underlying cement, modelled as perfectly fixed or perfectly unbonded, had a negligible effect on the predicted contact parameters. For a given radial clearance of 0.079 mm, the decrease in the thickness of the acetabular cup from 4.5 to 1.5 mm resulted in an increase in the contact half angle from 15° to 26°, and a decrease in the maximum contact pressure from 55 to 20 MPa. For a given acetabular cup thickness of 1.5 mm, a decrease in the radial clearance from 0.158 to 0.0395mm led to an increase in the contact half-angle from 20° to 30°, and a decrease in the maximum contact pressure from 30 to 10 MPa. For zero clearance, although the contact pressure was significantly reduced over most of the contact area, the whole acetabular cup came into contact with the femoral head, leading to stress concentration at the edge of the cup. Design optimization of the geometrical parameters, in terms of the acetabular cup thickness and the radial clearance, is important, not only to minimize the contact stress at the bearing surfaces, but also to avoid equatorial and edge contact.

scholarly journals Theoretical Basis of Face Contact Pressure Design of Zero-leakage Mechanical Seal

2021 ◽  
Author(s):  
Wei Zheng ◽  
Jianjun Sun ◽  
Chenbo Ma ◽  
Qiuping Yu
Keyword(s):  
Liquid Medium ◽  
Contact Pressure ◽  
Working Conditions ◽  
Pressure Range ◽  
Working Condition ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
Medium Temperature ◽  
The Face ◽  
Long Life

Abstract Based on the percolation theory, the critical porosity of zero-leakage at the wetting and non-wetting sealing interface working in liquid medium is first discussed. The influence of end-face frictional heat on end-face friction and wear is then investigated. The design criteria for the face contact pressure of mechanical seals with zero-leakage and long-life operation are established. Afterwards, the face contact pressure range of the mechanical seal working in conventional different liquid medium is calculated, and the influence of different working conditions speed, medium temperature and pressure on the face contact pressure range change is analyzed. Existing studies have shown that mechanical seals can achieve zero-leakage and long-life operation. As for the wettable sealing interface, the minimum face contact pressure, corresponding to the zero-leakage condition, is only related to the morphological parameters of the sealing interface, and has nothing to do with the sealing medium. Under the rotating and stationary rings physical parameters and given working conditions, the face contact pressure range of the sealing medium water and propane propylene is 0.477~1.132 MPa. The diesel sealing medium has a larger face contact pressure range than that of water and propane propylene, which can reach 0.477~2.183 MPa. The working condition speed, medium temperature and medium pressure have an influence on the face contact pressure range, while the influence of the working condition speed is the most significant.

Analysis of the Contact Deformation of a Radial Tire with Camber Angle

1995 ◽  
Vol 23 (1) ◽  
pp. 26-51 ◽  
Author(s):  
S. Kagami ◽  
T. Akasaka ◽  
H. Shiobara ◽  
A. Hasegawa
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Region ◽  
Contact Deformation ◽  
Contact Pressure Distribution ◽  
Radial Tire ◽  
Ring Model ◽  
Camber Angle ◽  
Contact Free ◽  
Good Agreement

Abstract The contact deformation of a radial tire with a camber angle, has been an important problem closely related to the cornering characteristics of radial tires. The analysis of this problem has been considered to be so difficult mathematically in describing the asymmetric deformation of a radial tire contacting with the roadway, that few papers have been published. In this paper, we present an analytical approach to this problem by using a spring bedded ring model consisting of sidewall spring systems in the radial, the lateral, and the circumferential directions and a spring bed of the tread rubber, together with a ring strip of the composite belt. Analytical solutions for each belt deformation in the contact and the contact-free regions are connected by appropriate boundary conditions at both ends. Galerkin's method is used for solving the additional deflection function defined in the contact region. This function plays an important role in determining the contact pressure distribution. Numerical calculations and experiments are conducted for a radial tire of 175SR14. Good agreement between the predicted and the measured results was obtained for two dimensional contact pressure distribution and the camber thrust characterized by the camber angle.

Experimental and Theoretical Study of the Contact Mechanics of Five Total Knee Joint Replacements

1995 ◽  
Vol 209 (4) ◽  
pp. 225-231 ◽  
Author(s):  
T Stewart ◽  
Z M Jin ◽  
D Shaw ◽  
D D Auger ◽  
M Stone ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Knee Joint ◽  
Contact Pressure ◽  
Contact Stress ◽  
Linear Elasticity ◽  
Contact Area ◽  
Elasticity Analysis ◽  
Joint Replacements ◽  
Total Knee ◽  
Maximum Contact

The tibio-femoral contact area in five current popular total knee joint replacements has been measured using pressure-sensitive film under a normal load of 2.5 kN and at several angles of flexion The corresponding maximum contact pressure has been estimated from the measured contact areas and found to exceed the point at which plastic deformation is expected in the ultra-high molecular weight polyethylene (UHMWPE) component particularly at flexion angles near 90°. The measured contact area and the estimated maximum contact stress have been found to be similar in magnitude for all of the five knee joint replacements tested. A significant difference, however, has been found in maximum contact pressure predicted from linear elasticity analysis for the different knee joints. This indicates that varying amounts of plastic deformation occurred in the polyethylene component in the different knee designs. It is important to know the extent of damage as knees with large amounts of plastic deformation are more likely to suffer low cycle fatigue failure. It is therefore concluded that the measurement of contact areas alone can be misleading in the design of and deformation in total knee joint replacements. It is important to modify geometries to reduce the maximum contact stress as predicted from the linear elasticity analysis, to below the linear elastic limit of the plastic component.

Analysis and Comparison of Seal Ability of Premium Tubing Connections under Axial Alternating Load

2013 ◽  
Vol 423-426 ◽  
pp. 2035-2039
Author(s):  
Long Cang Huang ◽  
Yin Ping Cao ◽  
Yang Yu ◽  
Yi Hua Dou
Keyword(s):  
Contact Pressure ◽  
Oil And Gas ◽  
Element Analysis ◽  
Gas Well ◽  
Cycle Number ◽  
Compression Load ◽  
Well Production ◽  
Maximum Contact ◽  
Contact Pressures ◽  
Better Than

In the process of oil and gas well production, tubing connection stand the axial alternating load during open well, shut well and fluid flow. In order to know premium connection seal ability under the loading, two types of P110 88.9mmx6.45mm premium tubing connections which called A connection and B connection are performed with finite element analysis, in which contact pressures and their the regularities distribution on sealing surface are analyzed. The results show that with the increasing of cycle number, the maximum contact pressures on sealing surface of both A connection and B connection are decreased. The decreasing of the maximum contact pressures on B connection is greater than those on A connection. With the increasing of cycle number of axial alternating compression load, the maximum contact pressure on sealing surface of A connection is decreased, and the maximum contact pressure on sealing surface of B connection remains constant. Compared the result, it shows that the seal ability of A connection is better than B connection under axial alternating tension load, while the seal ability of B connection is better than type A connection under axial alternating compression load.

Analysis of Premium Connection of Connecting and Sealing Ability Loaded by Axial Tensile Loads

2012 ◽  
Vol 268-270 ◽  
pp. 737-740
Author(s):  
Yang Yu ◽  
Yi Hua Dou ◽  
Fu Xiang Zhang ◽  
Xiang Tong Yang
Keyword(s):  
Finite Element ◽  
Contact Pressure ◽  
Tensile Load ◽  
Element Model ◽  
Sealing Ability ◽  
Axial Tensile ◽  
High Level ◽  
Maximum Contact ◽  
Contact Pressures ◽  
The Finite Element Model

It is necessary to know the connecting and sealing ability of premium connection for appropriate choices of different working conditions. By finite element method, the finite element model of premium connection is established and the stresses of seal section, shoulder zone and thread surface of tubing by axial tensile loads are analyzed. The results show that shoulder zone is subject to most axial stresses at made-up state, which will make distribution of stresses on thread reasonable. With the increase of axial tensile loads, stresses of thread on both ends increase and on seal section and shoulder zone slightly change. The maximum stress on some thread exceed the yield limit of material when axial tensile loads exceed 400KN. Limited axial tensile loads sharply influence the contact pressures on shoulder zone while slightly on seal section. Although the maximum contact pressure on shoulder zone drop to 0 when the axial tensile load is 600KN, the maximum contact pressure on seal section will keep on a high level.

Impact on Beams

1936 ◽  
Vol 3 (2) ◽  
pp. A55-A61
Author(s):  
H. L. Mason
Keyword(s):  
Historical Development ◽  
Contact Region ◽  
Local Deformation ◽  
Lateral Vibration ◽  
Transverse Impact ◽  
Concentrated Mass ◽  
Impact Theory ◽  
Inelastic Impact ◽  
Maximum Contact

Abstract This paper deals with transverse impact on beams the mass of which is of importance. Experimental results are presented for comparison with theory. Impacts which appear single to the eye are shown to consist in reality of several blows in quick succession. Section 1 of the paper traces the historical development of this subject by discussing the investigations of Young, Hodgkinson, Cox, Saint Venant, and Timoshenko. Section 2 treats a simplified system in which a concentrated mass strikes a smaller concentrated mass having a “soft” spring restraint. For elastic impact, theory predicts for the struck mass a path composed of sinusoidal elements separated by instantaneous blows. For inelastic impact it predicts a joint harmonic motion. Records of the paths of both masses were obtained experimentally. Section 3 of the paper uses Timoshenko’s method of combining local deformation of the contact region with lateral vibration of the beam. An experimental investigation of maximum contact pressure and of blow duration gives what is believed to be the first confirmation of this theory. Section 4 describes an experimental determination of flexural stresses in elastic and inelastic impact on a 3-in. I-beam by the use of a Westinghouse magnetic strain gage. The indication is that stresses may be higher than those calculated by the usual approximations.

CHANGES IN THE MORPHOMETRIC PARAMETERS OF THE BASILAR ARTERY WALL WHEN ITS COURSE IS GEOMETRICALLY ABNORMAL (KINKING AND COILING OF THE BASILAR ARTERY)

2020 ◽  
pp. 48-52
Author(s):  
Наталия Тимофеевна Алексеева ◽  
Светлана Валерьевна Клочкова ◽  
Дмитрий Борисович Никитюк ◽  
Арина Михайловна Карандеева ◽  
Анна Гуладиевна Кварацхелия
Keyword(s):  
Elastic Properties ◽  
Basilar Artery ◽  
Vascular Wall ◽  
Acute Angle ◽  
Morphometric Parameters ◽  
Geometric Configuration ◽  
Outer Diameter ◽  
Significant Excess ◽  
Study Results ◽  
Basilar Arteries

Цель - выявить закономерность изменения морфометрических параметров базилярной артерии при изменении геометрической конфигурации ее хода с формированием острого угла, спирали или петли. Материал и методы. Исследовали 16 нефиксированных макропрепаратов головного мозга. Анатомию базилярной артерии изучали методами макро-и микропрепарирования, проводили ангиоморфометрию с последующей обработкой результатов исследования. Результаты. В ходе ангиоморфометрии 16 базилярных артерий в 68,75 % случаев выявлен нормальный линейный ход сосуда. Величина показателя упругих свойств составила 0,33±0,01. В 31,25 % случаев выявлено изменение геометрической конфигурации хода базилярной артерии. В 40 % случаев от общего числа единиц с патологическим ходом сосуда формируется кинкинг базилярной артерии, в 60 % случаев - койлинг. Величина показателя упругих свойств составила 0,34±0,01, что существенно не отличается от средних значений для артерий мышечного типа. Исследование длины, толщины стенки, наружного диаметра и диаметра просвета сосудов показало значительное превышение данных показателей в сравнении с таковыми при нормальным линейном ходе артерий. Выводы. Данные, полученные в ходе исследования, свидетельствуют об увеличении наружного диаметра базилярной артерии, толщины сосудистой стенки и внутреннего просвета в случае образования кинкинга или койлинга. Objective - to reveal the pattern of changes in the morphometric parameters of the basilar artery when the geometric configuration of its course alters with the formation of an acute angle, spiral or loop. Material and methods. We studied 16 non-fixed human brain specimens. Anatomy of the basilar artery was studied by methods of macro- and micro-preparation, angiomorphometry was carried out with subsequent processing of the results of the study. Results. During angiomorphometry of 16 basilar arteries, normal straight course of the vessel was detected in 68,75 % of the cases. The value of the elastic properties index was 0,33±0,01. In 31,25 % of cases, a change in the geometric configuration of the course of the basilar artery was revealed. The basilar artery kinking was formed in 40 % and coiling - in 60 % of the total number of all cases with abnormal vessel course. The value of the elastic properties index was 0,34±0,01, which is not significantly different from the average values for muscle-type arteries. The study of the length, wall thickness, outer diameter and lumen diameter of the vessels showed a significant excess of these parameters in comparison with the vessels with normal linear course. Conclusions. The data obtained during the study indicate an increase in the outer diameter of the basilar artery, as well as an increase in the thickness of the vascular wall and the inner lumen in the case of kinking or coiling.

scholarly journals Elasto-plastic analysis of the contact region between a rigid ellipsoid and a semi-flat surface

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879739 ◽  
Author(s):  
Pengyang Li ◽  
Lingxia Zhou ◽  
Fangyuan Cui ◽  
Quandai Wang ◽  
Meiling Guo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Contact Pressure ◽  
Contact Region ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Effective Plastic Strain ◽  
Normal Forces ◽  
Von Mises

When the load acting on a mechanical structure is greater than the yield strength of the material, the contact surface will undergo plastic deformation. Cumulative plastic deformation has an important influence on the lifespan of mechanical parts. This article presents a three-dimensional semi-analytical model based on the conjugate gradient method and fast Fourier transform algorithm, with the aim of studying the characteristic parameters of the contact region between a rigid ellipsoid and elasto-plastic half-space. Moreover, normal forces and tangential traction were considered, as well as the contact pressure resulting from various sliding speeds and friction coefficients. The contact pressure, effective plastic strain, von Mises stress, and residual stress were measured and shown to increase with increasing sliding velocity. Finally, when the friction coefficient, contact pressure, and effective plastic strain are increased, the von Mises stress is also shown to increase, whereas the residual stress decreases.

Approximate Analytical Model for Hertzian Elliptical Wheel/Rail or Wheel/Crossing Contact Problems

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
F. D. Fischer ◽  
M. Wiest
Keyword(s):  
Contact Pressure ◽  
Contact Problems ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Technical Accuracy ◽  
Elliptical Contact ◽  
Current Approximation ◽  
Analytical Expressions ◽  
Maximum Contact ◽  
Hertzian Contact Theory

The Hertzian contact theory is approximated according to a concept by Tanaka (2001, “A New Calculation Method of Hertz Elliptical Contact Pressure,” ASME J. Tribol., 123, pp. 887–889) yielding simple analytical expressions for the elliptical semi-axes, the maximum contact pressure, the mutual approach and the contact spring constant. Several configurations are compared using the exact Hertz theory and the current approximation. The results agree within technical accuracy.

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