Variations in Contact Stress Distribution of Real Rough Surfaces During Running-In

1993 ◽  
Vol 115 (4) ◽  
pp. 602-606 ◽  
Author(s):  
Xian Liang ◽  
Ji Kaiyuan ◽  
Ju Yongqing ◽  
Chen Darong
Keyword(s):  
Plastic Deformation ◽  
Stress Distribution ◽  
Contact Stress ◽  
Dimensionless Parameter ◽  
Gradual Increase ◽  
Rough Surfaces ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Exponential Form ◽  
Contact Stress Distribution

A numerical model for the elastic contact of three-dimensional real rough surfaces has been developed and applied to the study of the variations in contact stress distribution in running-in process. The specimens for calculation and experiment are washers with nominally flat grinding surfaces. The stresses of real contact between specimens at each stage of running-in are calculated and the contact stress distributions are given. It is shown that the contact stress distribution is in an exponential form which could be characterized by one dimensionless parameter: λ, the index of contact stress distribution. The proportion of plastic deformation β may be expressed as a function of λ. The results of the present work confirm the reasonableness of the early opinion that the running-in process can be considered as a gradual increase in the elastic component of deformation of the contact area and a decrease in the proportion of plastic deformation.

Simple Model for Contact Stress of Strands Bent over Circular Saddles

2016 ◽  
Author(s):  
Sherif Mohareb ◽  
Arndt Goldack ◽  
Mike Schlaich
Keyword(s):  
Simple Model ◽  
Stress Distribution ◽  
Contact Force ◽  
Contact Stress ◽  
Flexural Rigidity ◽  
Strong Nonlinearity ◽  
Stress Distributions ◽  
Maximum Contact ◽  
Contact Stress Distribution ◽  
Peak Value

Cable-stayed and extra-dosed bridges are today widely used bridge types. Recently, saddles have been used to deviate strands of cables in the pylons. Up to now the mechanics of strands on saddles are not well understood. It was found, that typical longitudinal contact stress distributions between strand and saddle show a strong nonlinearity and a high peak value around the detachment point, where the strand meets the saddle. This paper presents a procedure to analyse the longitudinal contact stress distribution obtained by FEM calculations: This contact stress can be idealised as a constant contact stress according to the Barlow's formula and a contact force at the detachment point due to the flexural rigidity of the bent tension elements. An analytical model is provided to verify this contact force. Finally, a formula is presented to calculate the maximum contact stress. This study provides the basis for further research on saddle design and fatigue of strands.

The Interface Boundary Conditions for Bolted Flanged Connections

1976 ◽  
Vol 98 (4) ◽  
pp. 277-282 ◽  
Author(s):  
J. C. Thompson ◽  
Y. Sze ◽  
D. G. Strevel ◽  
J. C. Jofriet
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Plate Theory ◽  
Contact Region ◽  
Three Dimensional ◽  
Surface Region ◽  
Prestressing Force ◽  
Flange Thickness ◽  
Interface Boundary Conditions ◽  
Contact Stress Distribution

In most bolted connections, the unknown interface pressure distribution and the extent of the contact region are essential parameters in any stress analysis. Concerning these parameters, experimental and numerical studies of a model of an isolated single-bolt region show the following. The contact region between the flanges depends almost exclusively on the ratio of the flange thickness to the diameter of the surface region of each flange over which the bolt prestressing force is distributed; the contact zone is virtually independent of both the level of prestressing force and of the size of the bolt hole; and the contact stress distribution for a typical range of parameters is very closely approximated by a truncated conical distribution. The studies also delineate the regions of the flanges around each bolt where the stress state is strongly three-dimensional and regions where simple plate theory is applicable. The relationships established between the contact stress distribution and the various geometric parameters are presented in a form immediately applicable by designers.

An Analysis of Circular Bolted Flanged Joints on Solid Round Bars Subjected to External Bending Moments

2000 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Tsuneshi Morohoshi ◽  
Akihiro Shimizu
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Three Dimensional ◽  
Bending Moment ◽  
Theory Of Elasticity ◽  
Load Factor ◽  
Bending Moments ◽  
Sealing Performance ◽  
Contact Stress Distribution ◽  
Good Agreement

Abstract In designing bolted joints, it is important to know the contact stress distribution which governs the clamping effect or the sealing performance and to estimate the load factor (the ratio of an increment in axial bolt force to an external load) from bolt design standpoint. The clamping force by bolts and the external bending moment are axi-asymmetrical loads and not many investigations have seen reported which treat axi-asymmetrical. In this paper, the clamping effect, and the load factor for the case of solid round bars with circular flanges, subjected to external bending moments, are analyzed as an axi-asymmetrical problem using the three-dimensional theory of elasticity. Experiments were carried out concerning the contact stress distribution, and the load factor for the external bending moment (a relationship between an increment in axial bolt force, and external bending moment). The analytical results were in fairly good agreement with the experimental ones.

Analysis of Cord-Reinforced Poly-Rib Serpentine Belt Drive With Thermal Effect

2005 ◽  
Vol 127 (6) ◽  
pp. 1198-1206 ◽  
Author(s):  
G. Song ◽  
K. Chandrashekhara ◽  
W. F. Breig ◽  
D. L. Klein ◽  
L. R. Oliver
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Three Dimensional ◽  
Single Layer ◽  
Material Model ◽  
Element Model ◽  
Shear Angle ◽  
Velocity Variation ◽  
Serpentine Belt ◽  
Contact Stress Distribution

This paper investigates the operation of an automotive poly-rib serpentine belt system. A three-dimensional dynamic finite element model, consisting of a driver pulley, a driven pulley, and a complete five-rib V-ribbed belt, was created. Belt construction accounts for three different elastomeric compounds and a single layer of reinforcing cords. Rubber was considered incompressible hyperelastic material, and cord was considered linear elastic material. The material model accounting for thermal strains and temperature-dependent properties of the rubber solids was implemented in ABAQUS∕EXPLICIT code for the simulation. A tangential shear angle and an axial shear angle were defined to quantify shear deformations. The shear angles were found to be closely related to velocity variation along contact arc and the imbalanced contact stress distribution on different sides of the same rib and on different ribs. The temperature effect on shear deformation, tension and velocity variation, and contact stress distribution was investigated and shown in comparison to the results for the same system operating at room temperature.

FEM Stress Analyses of the Contact Stress Distributions at the Bearing Surfaces in Bolted Joints Using Hexagon Bolts With Flanges

2010 ◽  
Author(s):  
Yukio Morozumi ◽  
Masahiko Okumura ◽  
Toshiyuki Sawa ◽  
Kengo Kuwaki
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Slope Angle ◽  
Bolted Joints ◽  
Stress Distributions ◽  
Bearing Surface ◽  
Permanent Set ◽  
Flange Thickness ◽  
The Difference ◽  
Contact Stress Distribution

In designing bolted joints, it is important to understand the contact stress distribution and permanent set at the bearing surface in the case of high initial axial tension. They are investigated using elasto-plastic FEM for hexagon bolts with flange. It is found that the difference in the contact stress distribution is large between elastic FEM and elasto-plastic FEM. Effects of the flange thickness and the flange slope angle on the contact stress distribution and permanent set are examined, and it is shown that they are substantially influential. In the experiments, hollow cylindrical specimens are compressed by the bolts with flange and permanent sets are measured at the bearing surface. The permanent sets are compared with permanent sets obtained from the elasto-plastic FEM and they are in a fairly good agreement. In addition, the equivalent length for the hexagon bolt with flange is proposed.

An Analytical Model for Predicting Contact Stress and Sliding Wear of a Three-Dimensional Textured Surface

2009 ◽  
Author(s):  
Elon J. Terrell ◽  
C. Fred Higgs
Keyword(s):  
Stress Distribution ◽  
Stress Analysis ◽  
Analytical Model ◽  
Contact Stress ◽  
Sliding Wear ◽  
Flat Surface ◽  
Three Dimensional ◽  
Textured Surface ◽  
Two Dimensional ◽  
Contact Stress Distribution

In this paper, an analytical model for predicting the contact stress and wear distribution between a textured surface and a compliant flat is presented. The modeling formulation is based upon a two-dimensional stress analysis of the flat, and it allows the contact stress distribution to be found from the distribution of the sample deflection into the flat surface. The wear evolution was calculated from the contact stress.

scholarly journals Numerical study on the applicability to manufacturing of contact-stress-optimised shaft-hub connections joined by lateral extrusion

2020 ◽  
Vol 7 ◽  
pp. 21
Author(s):  
Robert Jean-Phillipp Meissner ◽  
Mathias Liewald ◽  
Daniel Ulrich ◽  
Hansgeorg Binz
Keyword(s):  
Plastic Deformation ◽  
Stress Distribution ◽  
Contact Stress ◽  
Numerical Study ◽  
High Sensitivity ◽  
Industrial Applications ◽  
Negative Effects ◽  
Lateral Extrusion ◽  
Manufacturing Tolerances ◽  
Contact Stress Distribution

Shaft-hub connections, which are joined by plastic deformation of at least one component (e.g. joining by lateral extrusion), can meet today's contradictory requirements for high power densities with low manufacturing costs. As opposed to classical manufacturing methods, the tight manufacturing tolerances of shafts and hubs are not required here since the shaft is formed in the hub during the process to generate a combined frictional and positive-locking connection. However, plastic deformation generally results in an uneven distribution of contact stress, which causes negative effects such as increased hub stress and deformation, as well as the reduced transmission capacity of the connection. To overcome this effect, an iterative design approach for plastically stressed shaft-hub connections was developed in Ulrich et al. (2019)[1], in which the contact-stress distribution is influenced by contouring of the hub contact surface. Nonetheless, one major challenge in this process is the high sensitivity of the stress distribution to contour changes, particularly in the edge area of the connection, meaning that a dependency on tight manufacturing tolerances is present here, too. Therefore, an investigation is conducted to determine the extent to which deviations in the manufacturing process of the components, in the tool quality and during joining by lateral extrusion influence the resulting contact stress. In order to achieve this goal, numerical investigations are carried out, and the effects on the resulting contact-stress distribution are analysed. Finally, recommendations for manufacturing accuracy and process limits are derived in order to ensure manufacturability and enable the transfer of technology to industrial applications involving shaft-hub connections joined by lateral extrusion.

Contact stress variations near the insulated rail joints

2002 ◽  
Vol 216 (4) ◽  
pp. 265-273 ◽  
Author(s):  
Y. C. Chen ◽  
J. H. Kuang
Keyword(s):  
Contact Stress ◽  
Three Dimensional ◽  
Hertzian Contact ◽  
Stress Distributions ◽  
Linear Elastic ◽  
Contact Points ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Stress Variations ◽  
Contact Stress Distribution

The effect of an insulated rail joint (IRJ) on the contact stress variation near wheel-rail contact zones was simulated by employing three-dimensional finite element models. Three linear elastic IRJ materials, i.e. epoxy-fibreglass, polytetrafluoroethylene (PTFE) and Nylon-66, were investigated. Contact elements were used to simulate the interaction between the wheel and rail contact points. Numerical results showed that the presence of IRJ might significantly affect the wheel-rail contact stress distributions. Results also indicated that the traditional Hertzian contact theory is no longer available to predict the contact stress distribution around the rail joints.

Elastoplastic Frictional Contact Study on Interference Fits of Compressor

2011 ◽  
Vol 211-212 ◽  
pp. 535-539
Author(s):  
Ai Hua Liao
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Frictional Contact ◽  
Contact Problems ◽  
Boundary Problems ◽  
Interference Fit ◽  
Parametric Variational Principle ◽  
Design And Manufacturing ◽  
Contact Stress Distribution ◽  
Fit Tolerance

The impeller mounted onto the compressor shaft assembly via interference fit is one of the key components of a centrifugal compressor stage. A suitable fit tolerance needs to be considered in the structural design. A locomotive-type turbocharger compressor with 24 blades under combined centrifugal and interference-fit loading was considered in the numerical analysis. The FE parametric quadratic programming (PQP) method which was developed based on the parametric variational principle (PVP) was used for the analysis of stress distribution of 3D elastoplastic frictional contact of impeller-shaft sleeve-shaft. The solution of elastoplastic frictional contact problems belongs to the unspecified boundary problems where the interaction between two kinds of nonlinearities should occur. The effect of fit tolerance, rotational speed and the contact stress distribution on the contact stress was discussed in detail in the numerical computation. The study play a referenced role in deciding the proper fit tolerance and improving design and manufacturing technology of compressor impellers.

Finite Element Analysis of Poor Distal Contact of the Femoral Component of a Cementless Hip Endoprosthesis

1993 ◽  
Vol 207 (4) ◽  
pp. 255-261 ◽  
Author(s):  
M Taylor ◽  
E W Abel
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Hip Endoprosthesis ◽  
Applied Loading ◽  
Femoral Geometry ◽  
Contact Models

The difficulty of achieving good distal contact between a cementless hip endoprosthesis and the femur is well established. This finite element study investigates the effect on the stress distribution within the femur due to varying lengths of distal gap. Three-dimensional anatomical models of two different sized femurs were generated, based upon computer tomograph scans of two cadaveric specimens. A further six models were derived from each original model, with distal gaps varying from 10 to 60 mm in length. The resulting stress distributions within these were compared to the uniform contact models. The extent to which femoral geometry was an influencing factor on the stress distribution within the bone was also studied. Lack of distal contact with the prosthesis was found not to affect the proximal stress distribution within the femur, for distal gap lengths of up to 60 mm. In the region of no distal contact, the stress within the femur was at normal physiological levels associated with the applied loading and boundary conditions. The femoral geometry was found to have little influence on the stress distribution within the cortical bone. Although localized variations were noted, both femurs exhibited the same general stress distribution pattern.

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