An Elastic-Plastic Analysis of Profile Evolution in Cylindrical Roller Bearings

2012 ◽  
Author(s):  
Spiridon S. Creţu ◽  
Marcelin I. Benchea
Keyword(s):  
Residual Stresses ◽  
Pressure Distribution ◽  
Kinematic Hardening ◽  
Stable State ◽  
Elastic Analysis ◽  
Elastic Plastic ◽  
Roller Bearings ◽  
Plastic Analysis ◽  
Roller Profile ◽  
Cylindrical Roller

The roller profile appears to be the key element to attain a longer rating life for both cylindrical and tapered roller bearings. A genuine elastic analysis is able to optimize the roller profile to obtain a stress distribution in the contact zones that provides enhanced operational reliability and greater insensitivity to misalignment. For traditional cylindrical-crowned roller profile design class I discontinuities exist at the intersection points of roller profile with the crowning radius as well as at the end chamfer. In an elastic analysis these discontinuities generate very sharp increases in pressure distribution diminishing the rating life of the bearing. In fact, these local increases in pressure distribution are able to overcome, locally, the yield limit and to induce both plastic deformations and residual stresses. After a certain number of cycles the material will shakedown elastically to a slightly modified roller profile and a stable state of compressive residual stresses. If were taken place, these changes have to be considered in the life evaluation. An analysis model has been developed to simulate the nonlinear strain rate dependent deformation of rolling bearing steel stressed in the elastic-plastic domain. The model is developed in the frame of the incremental theory of plasticity by using the von Mises yield criterion and Prandtl-Reuss equations. By considering an isotropic and non-linear kinematic hardening laws the model accounts for the cyclic hardening phenomena. For each new load increment new increments for the components of stress and strain tensors, but also increments of residual stresses, are computed for each point of the 3D mesh. Both the new contact geometry and residual stresses distributions, are further considered as initial values for the next loading cycle, the incremental technique being reiterated. The cyclic evaluation process of both the plastic strains and residual stresses is performed until the material shakedowns. For the case of cylindrical roller bearings with cylindrical-crowned roller profile, the role played by the crowning geometry on pressure distribution is pointed out for both the elastic analysis and elastic-plastic analysis. Further, the modified rating lives are evaluated using the methodology given in ISO 16281-2008.

Elastic-Plastic Analysis of Fretting Contacts

2015 ◽  
Vol 642 ◽  
pp. 248-252
Author(s):  
Chang Hung Kuo
Keyword(s):  
Kinematic Hardening ◽  
Carbon Steels ◽  
Plastic Behavior ◽  
Rule Based ◽  
Elastic Plastic ◽  
Hardening Rule ◽  
Chaboche Model ◽  
Plastic Analysis ◽  
Finite Element Procedure ◽  
Elastic Shakedown

A finite element procedure is implemented for the elastic-plastic analysis of carbon steels subjected to reciprocating fretting contacts. The nonlinear kinematic hardening rule based on Chaboche model is used to model the cyclic plastic behavior in fretting contacts. The results show that accumulation of plastic strains, i.e. ratchetting, may occur near the contact edge while elastic shakedown is likely to take place in substrate.

The Elastic-Plastic Analysis of Tubes—IV: Thermal Ratchetting

1992 ◽  
Vol 114 (2) ◽  
pp. 236-245 ◽  
Author(s):  
W. Jiang
Keyword(s):  
Steady State ◽  
Plastic Strain ◽  
Centrifugal Force ◽  
Kinematic Hardening ◽  
Elastic Plastic ◽  
External Pressures ◽  
Plastic Analysis ◽  
Steady Solutions ◽  
Number Of Cycles

This paper continues the investigation of the shakedown behavior of tubes subjected to cyclic centrifugal force and temperature, and sustained internal and external pressures. It is found that when ratchetting occurs, the plastic strain builds up with each cycle, but finally reaches a steady state after a large number of cycles for kinematic hardening materials. The steady solutions for three kinds of ratchetting behavior are found and given in this paper.

An Analytical Approach to Elastic-Plastic Stress Analysis of Rolling Contact

1994 ◽  
Vol 116 (3) ◽  
pp. 577-587 ◽  
Author(s):  
Yanyao Jiang ◽  
Huseyin Sehitoglu
Keyword(s):  
Residual Stresses ◽  
Stress Analysis ◽  
Analytical Approach ◽  
Kinematic Hardening ◽  
Tangential Force ◽  
Rolling Contact ◽  
Approximate Determination ◽  
Elastic Plastic ◽  
Surface Plasticity ◽  
Plastic Stress

Based on a stress invariant hypothesis and a stress/strain relaxation procedure, an analytical approach is forwarded for approximate determination of residual stresses and strain accumulation in elastic-plastic stress analysis of rolling contact. For line rolling contact problems, the proposed method produces residual stress distributions in favorable agreement with the existing finite element findings. It constitutes a significant improvement over the Merwin-Johnson and the McDowell-Moyar methods established earlier. The proposed approach is employed to study combined rolling and sliding for selected materials, with special attention devoted to 1070 steel behavior. Normal load determines the subsurface residual stresses and the size of the subsurface plastic zone. On the other hand, the influence of tangential force penetrates to a depth of 0.3a, where a is the half width of the contact area, and has diminishing influence on the residual stresses beyond this thin layer. A two-surface plasticity model, commensurate with nonlinear kinematic hardening, is utilized in solution of incremental surface displacements with repeated rolling. It is demonstrated that a driven wheel undergoes greater plastic deformation than the driving wheel, suggesting that the driven wheel experiences enhanced fatigue damage. Furthermore, the calculated residual stresses are compared with the existing experimental data from the literature with exceptional agreements.

Proposal of Use of Mises Criteria for Elastic Analysis in Appendix 9 of ASME Section VIII Division 3

2020 ◽  
Author(s):  
Susumu Terada
Keyword(s):  
Flow Stress ◽  
Plastic Collapse ◽  
Elastic Analysis ◽  
Stress Evaluation ◽  
Stress Theory ◽  
Elastic Plastic ◽  
Primary Stress ◽  
Plastic Analysis ◽  
Section Viii ◽  
Von Mises

Abstract The stress evaluation by elastic analyses for protection against plastic collapse in Appendix 9 is based on maximum shear stress theory (Tresca theory). On the other hand, the stress evaluation by elastic-plastic analysis and design equations by flow stress for design pressure for cylindrical shell and spherical shell in KD-221 is based on distortion energy yield stress theory (von Mises theory). With regard to materials with low and intermediate Sy/Su, in particular the primary stress evaluation based on Tresca stress for elastic analysis in current Div.3 is much more conservative than that based on flow stress equations similar to elastic-plastic analysis from experimental results. In Section VIII Div.2, von Mises yield criterion is used for stress evaluation for elastic analysis because it matches experimental results more closely than Tresca yielding criterion and is also consistent with plasticity algorithms used in elastic-plastic analysis. Therefore in Div.3 von Mises stress should be used for elastic analysis in the same way as in Sec. VIII Div.2. For materials with high Sy/Su, the primary stress evaluation based on von Mises criterion for elastic analysis is less conservative than that based on flow stress equations similar to elastic-plastic analysis because of a difference in design factor of 1.5 for elastic analysis and 1.732 for flow stress equations. Therefore, we propose using von Mises criterion for protection against plastic collapse with design correction factor using Sy/Su in Appendix 9 in order to remove excessive conservativeness for materials with low and intermediate Sy/Su. The validity of this proposal is shown in this paper.

A Shell-Element–Based Elastic Analysis Predicting Welding-Induced Distortions for Ship Panels

2007 ◽  
Vol 51 (02) ◽  
pp. 128-136
Author(s):  
Gonghyun Jung
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Shell Element ◽  
Significant Loss ◽  
Buckling Analysis ◽  
Elastic Analysis ◽  
Plastic Strains ◽  
Elastic Plastic ◽  
Distortion Analysis ◽  
Plastic Analysis

A new numerical model, Q-Weld (Edison Welding Institute, Columbus, OH), which is a shell-element-based elastic analysis, is proposed for the prediction of the distortion induced in ship panels. Based on the results of the three-dimensional thermal-elastic-plastic analyses, it was found that the shell element-based model excluding the geometry of fillet welds and including only transverse and longitudinal plastic strains is valid without significant loss of accuracy. The developed Q-Weld predicts well-agreed distortions with the three-dimensional thermal-elastic-plastic analysis and demonstrates its potential in welding-induced distortion analysis, including buckling analysis.

A Simplified Technique for Shakedown Load Determination of a 90 Degree Pipe Bend Subjected to Constant Internal Pressure and Cyclic In-Plane Bending

2005 ◽  
Author(s):  
Hany F. Abdalla ◽  
Maher Y. A. Younan ◽  
Mohammed M. Megahed
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Internal Pressure ◽  
High Heat ◽  
Heat Fluxes ◽  
Elastic Analysis ◽  
Pipe Bend ◽  
Elastic Plastic ◽  
Plastic Analysis ◽  
Plane Bending

In this paper a simple technique is presented to determine the shakedown load of a 90 degree pipe bend subjected to constant internal pressure and cyclic in-plane bending using the finite element method. Through the proposed technique, the shakedown load is determined without performing time consuming cyclic loading simulations or conventional iterative elastic techniques. Instead, the shakedown load is determined through performing only two analyses namely; an elastic analysis and an elastic-plastic analysis. By extracting the results of the two analyses, the shakedown load is determined through the calculation of the residual stresses developed in the pipe bend. In the elastic analysis, performed only once and stored, an in-plane closing moment is applied preserving structure stresses within the material elastic range. In the elastic-plastic analysis, a constant internal pressure, below the pressure to cause yielding, is applied in addition to an increasing moment magnitude that causes the material yield strength to be exceeded. For verification purposes, the results of the simplified technique are compared to the results of full cyclic loading finite element simulations where the pipe bend is subjected to constant internal pressure and cyclic in-plane closing moment loading. In order to have confidence in the proposed technique, it is applied beforehand on the Bree cylinder [1] subjected to constant internal pressure and cyclic high heat fluxes across its wall. The results of the proposed technique showed very good correlation with the, analytically determined, Bree diagram of the cylinder.

Study on Collapse Characteristics and CSRF Method for 45 Deg Cylinder-to-Cylinder Intersections

2012 ◽  
Author(s):  
Takuro Honda ◽  
Shunji Kataoka ◽  
Takuya Sato
Keyword(s):  
Plastic Strain ◽  
High Stress ◽  
Elastic Analysis ◽  
Collapse Pressure ◽  
Elastic Plastic ◽  
Replacement Method ◽  
Inelastic Analysis ◽  
Collapse Strength ◽  
Collapse Characteristics ◽  
Plastic Analysis

It is known that the collapse strength of complex three dimensional structures is hard to evaluate accurately with elastic analysis, and more accurate results require the use of inelastic analysis. A cylinder-to-cylinder acute lateral intersection is one of basic structures of process plants. It is known that a high stress concentration occurs at an acute lateral more than 90 deg-lateral. In general, the area replacement method and the elastic analysis are applied for the design of acute lateral. However, these results may provide overly-conservative designs. In the previous work, the authors proposed CSRF (Collapse Strength Reduction Factor) method. The CSRF was defined as a ratio of the simple cylinder collapse pressure to the cylinder-to-cylinder collapse pressure. The proposed CSRF method provided more reasonable design than the elastic analysis. In this paper, the concept of the CSRF was redefined by using the maximum allowable working pressure. The CSRF were evaluated on the 45 deg and 90 deg-laterals based on the area replacement method, the elastic analysis, the limit load analysis and the elastic plastic analysis to study the collapse characteristics of 45 deg-laterals. The 45 deg-laterals are weaker than 90 deg-laterals, and inelastic analysis provides greater strength of 45 deg-laterals than elastic analysis. The results of elastic plastic analysis showed that overly-large plastic strain occurs on 45 deg-laterals. This plastic strain should be evaluated in addition to the collapse pressure.

The Elastic-Plastic Analysis of Tubes—I: General Theory

1992 ◽  
Vol 114 (2) ◽  
pp. 213-221 ◽  
Author(s):  
W. Jiang
Keyword(s):  
General Theory ◽  
Constitutive Equations ◽  
Kinematic Hardening ◽  
Elastic Plastic ◽  
Hardening Rule ◽  
Plastic Analysis ◽  
Made In

A study is made in this paper of the elastic-plastic analysis of tubes subjected to various loads and temperatures. The kinematic hardening rule is used in the analysis and constitutive equations are developed for the tube problems. By piecing several elastic and plastic solutions together, various tube problems can be solved in closed forms.

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