scholarly journals Optimization of Contact Edge Profile for Minimizing Contact Pressure in a Press-fitted Shaft

2018 ◽  
Vol 165 ◽  
pp. 22029 ◽  
Author(s):  
Dong-Hyung Lee ◽  
Ha-Young Choi ◽  
Seok-Jin Kwon ◽  
Jeong-Won Seo

In the shrink or press-fitted shafts such as railway axles, the rotor of a steam turbine or coupling, a high-stress concentration takes place in the close of contact edge due to relative slip between shaft and boss in a press-fitted shaft and this is a major cause of fatigue failure of the shaft. The object of this paper is to build a finite element analysis model for analysing press-fitted and bending load condition in a pressfitted assembly and is to propose a hub shape optimization method to minimize a contact pressure in the close of shaft contact edge. Numerical asymmetric-axisymmetric finite element model was developed to predict the contact stress state of the press-fitted shaft. Global optimization method, genetic algorithm, and local optimization method, sequential quadratic programming, was applied to the press-fitted assembly to optimize the hub contact edge geometry. The results showed that the maximum contact pressure with optimized hub shape decreased more than 60% compared to conventional hub shape, the maximum contact stress affecting fatigue life reduced about 47%. In addition, hub shape optimization design could be a useful tool, able to increase the load capabilities of press fits concerning wear and fatigue behaviour.

Author(s):  
T Stewart ◽  
Z M Jin ◽  
D Shaw ◽  
D D Auger ◽  
M Stone ◽  
...  

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.


2012 ◽  
Vol 268-270 ◽  
pp. 737-740
Author(s):  
Yang Yu ◽  
Yi Hua Dou ◽  
Fu Xiang Zhang ◽  
Xiang Tong Yang

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.


Author(s):  
Zhonglai Wang ◽  
Bo Yang ◽  
Hong-Zhong Huang ◽  
Qiang Miao ◽  
Dan Ling

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.


2013 ◽  
Vol 442 ◽  
pp. 229-232 ◽  
Author(s):  
Li Mei Wu ◽  
Fei Yang

According to the cutting theory of involute tooth profile, established an exact three-dimensional parametric model by UG. Used ABAQUS to crate finite element model for gear meshing. After simulated the meshing process, discussed the periodicity of the tooth surface contact stress. Based on the result of finite element analysis, made a comparison of the maximum contact stress between finite element solution and Hertz theoretical solution, analyzed the contact stress distribution on tooth width, and researched the effect of friction factor on contact stress. All that provided some theoretical basis for gear contact strength design.


Author(s):  
Chris Alexander ◽  
Wade Armer ◽  
Stuart Harbert

KOCH Heat Transfer Company contracted Stress Engineering Services, Inc. to perform a design/parameter study of a return bonnet used in hairpin heat exchangers that employs an elliptical flange design. The return bonnet is an important component of the heat exchanger as it can be removed to permit inspection of the heat exchanger tubes. The return bonnet is bolted to the hairpin leg flange. To maintain sealing integrity a gasket is placed between the return bonnet flange and the hairpin leg flange. The sealing efficiency of two return bonnet sizes (24-inch and 30-inch) was investigated in this study using finite element analysis. The sealing efficiency is an indication of how the contact pressure changes circumferentially around the gasket and is calculated by dividing the local contact pressure by the maximum contact pressure calculated in the gasket for each respective design. The study assessed the effects of geometric changes to the mating flanges. Using an iterative design process using finite element analysis, the elliptical flanges were optimized to maximize sealing efficiency. Upon completion of the study, the manufacturer successfully employed the modifications as evidenced with multiple successful hydrotests.


Author(s):  
Li Yuan ◽  
Han Bao ◽  
Xuefeng Yao ◽  
Jianguo Lu ◽  
Jie Liu

The pressure distribution of conformal contact in spherical plain bearings is studied adopting both theoretical methods and finite element simulations. The effects of normal loads and friction coefficients on the distribution of both axial and circumferential contact stress are investigated. The results show that the circumferential stress can be exactly described with the complete spherical conformal contact theory while the axial one presents strong free-edge effects, mainly caused by the compressive strain. In addition, the distribution of contact stress tends to be uniform with the increase of the load and the friction coefficient, referring to a decrease of contact pressure in the central region and a rise on both edges of the outer ring, which can be attributed to the obstruction effects of friction on the deformation of bearings and the corresponding alteration of contact area.


Author(s):  
Louay S. Yousuf ◽  
Yaakob K. H. Dabool

Abstract The bending deflection of the disc cam profile and the dynamic response of the follower were discussed and analyzed for three paths of contact. The objective of this paper was to study the influence of maximum contact pressure on the bending deflection of the cam profile. Numerical simulation was carried out using SolidWorks Software to simulate the follower displacement, velocity and acceleration. Finite element analysis was used taking into account the use of ANSYS package to calculate the bending deflection. The experiment setup had been done through an infrared camera device. The bending deflection of point (18) is bigger than the bending deflection of point (4) because of the bigness of radius of curvature of nose (2).


2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Sunghwan Kim ◽  
Mark Carl Miller

A finite element (FE) elbow model was developed to predict the contact stress and contact area of the native humeroradial joint. The model was validated using Fuji pressure sensitive film with cadaveric elbows for which axial loads of 50, 100, and 200 N were applied through the radial head. Maximum contact stresses ranged from 1.7 to 4.32 MPa by FE predictions and from 1.34 to 3.84 MPa by pressure sensitive film measurement while contact areas extended from 39.33 to 77.86 mm2 and 29.73 to 83.34 mm2 by FE prediction and experimental measurement, respectively. Measurements from cadaveric testing and FE predictions showed the same patterns in both the maximum contact stress and contact area, as another demonstration of agreement. While measured contact pressures and contact areas validated the FE predictions, computed maximum stresses and contact area tended to overestimate the maximum contact stress and contact area.


2011 ◽  
Vol 130-134 ◽  
pp. 2306-2310
Author(s):  
Yan Gang Wei ◽  
Meng Sun

According to the theory of contact mechanics, the radial stiffness, the maximum contact stress, and the maximum radial load of pre-loaded cylindrical roller bearings, including both solid roller and hollow roller bearings, are calculated with the finite element method. The effects of load on the radial stiffness, the maximum contact stress, and the maximum radial load of bearing are analyzed. The analysis results show that the effect of load on the radial stiffness is complex. Under the different magnitude loads, the effects of both hollowness and interference magnitude on the radial stiffness and on the maximum contact stress are not same. Thus the effects of load magnitude must be considered in the design and application of pre-loaded cylindrical roller bearings.


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