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.

The Elastic-Plastic Analysis of Tubes—III: Shakedown Analysis

1992 ◽  
Vol 114 (2) ◽  
pp. 229-235 ◽  
Author(s):  
W. Jiang
Keyword(s):  
Steady State ◽  
Centrifugal Force ◽  
Kinematic Hardening ◽  
Steady States ◽  
Shakedown Analysis ◽  
Elastic Plastic ◽  
External Pressures ◽  
Plastic Analysis ◽  
Elastic Shakedown ◽  
Steady State Solutions

This paper presents an investigation of the shakedown behavior of tubes subjected to cyclic centrifugal force and temperature, and sustained internal and external pressures. It is found that the steady states can always be attained as a result of the kinematic hardening. Then, when shakedown occurs, the stresses and strains will cycle between the cooling state and the heating state. The steady-state solutions for the cases of elastic shakedown and reversed plasticity are discussed and given in this paper.

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.

Effects of Local Peak Stress Distribution on the Ratchet Limit

2002 ◽  
Author(s):  
Nobuyoshi Yanagida ◽  
Masaaki Tanaka ◽  
Norimichi Yamashita ◽  
Yukinori Yamamoto
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Plastic Strain ◽  
Equivalent Stress ◽  
Equivalent Plastic Strain ◽  
Peak Stress ◽  
Element Analysis ◽  
Stress Evaluation ◽  
Elastic Plastic ◽  
Plastic Analysis

Alternative stress evaluation criteria suitable for Finite Element Analysis (FEA) proposed by Okamoto et al. [1],[2] have been studied by the Committee on Three Dimensional Finite Element Stress Evaluation (C-TDF) in Japan. Thermal stress ratchet criteria in plastic FEA are now under consideration. Two criteria are proposed: (1) Evaluating variations in plastic strain increments, and (2) Evaluating the width of the area in which Mises equivalent stress exceeds 3Sm. To verify of these criteria, we selected notched cylindrical vessel models as prime elements. To evaluate the effect of the local peak stress distribution on these criteria, cylindrical vessels with a semicircular notch on the outer surface were selected for this analysis. We used two notch configurations for our analysis, and the stress concentration factor for the notches was set to 1.5 and 2.0. We conducted elastic-plastic analysis to evaluate the ratchet limit. Sustained pressure and alternating enforced longitudinal displacements which causes secondary stress were used as parameters for the elastic-plastic analysis. We found that when no ratchet was observed, the equivalent plastic strain increments decreased and the area in which Mises equivalent stress exceeds 3Sm are below the certain range.

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.

Comparative Study on the Nonlinear Calculation of Ratcheting Deformation Using Different Constitutive Model

2020 ◽  
Author(s):  
Xuejiao Shao ◽  
Hai Xie ◽  
Furui Xiong ◽  
Xiaolong Fu ◽  
Kaikai Shi ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Constitutive Model ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Fatigue Analysis ◽  
Constitutive Law ◽  
Elastic Plastic ◽  
Bending Strain ◽  
Cumulative Strain ◽  
Membrane Strain

Abstract In the fatigue assessment of nuclear components following the RCC-M B3200, if the results using the simplified elastic-plastic method cannot meet the Code’s requirements, it is necessary to conduct a detailed elastic-plastic fatigue analysis of the component. In this paper, the A-F and Chaboche nonlinear kinematic hardening constitutive models are used to conduct an elasto-plastic fatigue analysis for a typical nozzle component, aiming to calculate the secondary cumulative cyclic plastic strain of the structure induced by the rapid temperature change transient. The calculation method of nonlinear ratcheting behavior under cyclic loading is studied. The method of determining the parameters of constitutive model based on cyclic stable stress-strain curve is also studied. A sensitive study of the parameters for the same constitutive law is presented, including the results of cumulative plastic strain. The ratcheting behavior simulation calculated by different constitutive models are compared. The results show that the A-F model has a conservative prediction of ratcheting behavior as the dynamic recovery term is too strong. It was found that the Chaboche constitutive model is the better methodology for ratcheting analysis. In order to evaluate the bearing ability of the section, the membrane strain and bending strain is obtained by linearizing the node strain along the cross section. The ratios of membrane strain and membrane plus bending strain to total strain are calculated, which is helpful to determining the limit criteria for the cumulative strain of structures.

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.

Plastic Strain of GlidCop for Materials of High Heat Load Components

2013 ◽  
Vol 772 ◽  
pp. 123-127 ◽  
Author(s):  
Mutsumi Sano ◽  
Sunao Takahashi ◽  
Atsuo Watanabe ◽  
Hideo Kitamura ◽  
Ayumi Shiro ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Heat Load ◽  
High Heat ◽  
Analytic Solutions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plastic Analysis ◽  
High Heat Load ◽  
Number Of Cycles

We investigated the plastic strain of GlidCopTM, copper that is dispersion strengthened with aluminum oxide, by X-ray diffraction using synchrotron radiation. The purpose of this study is to verify the accuracy of the elastic-plastic analysis, which has been employed to predict the fatigue life of GlidCop. As a result, the plastic strain was estimated to be 0.7- 1.3% at any number of cycles, which is slightly smaller than the analytic solutions.

Thermal Elastic-Plastic Stress Analysis of Structural Elements With Creep

2005 ◽  
Author(s):  
R. Sarala ◽  
B. Sutharson ◽  
D. Jaya Kanth
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Kinematic Hardening ◽  
Transient State ◽  
Structural Elements ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Plastic Analysis ◽  
Plastic Stress

Finite element analysis of thermo-mechanical problems is reported here. From the literature, it may be seen that the thermal-elastic plastic analysis of structural elements has continued to remain a research topic for a couple of decades. No one computationally verified the thermal elastic plastic stress analysis with creep using triangular elements or quadrilateral elements. Finite element analysis code TSAP (Thermal Structural Analysis Programme) was developed in FORTRAN to handle the elastic-plastic stress analysis on two-dimensional planar or three dimensional axisymmetry structures subjected to combined thermal and mechanical loads. In this work, thermo elastic plastic analysis is extended to creep support. A triangular or quadrilateral element has been used to analysis of structures with inclusion of creep. The formulation is based on isotropic or kinematic hardening rule. The validation checks on the program are carried out using results available in the literature. The parameters are considered while analyses are (1.) Type of materials used (2.) Type of elements used (3.) Structure geometry (axisymmetry, plane stress or plane strain) (3.) Type of analysis (steady state or transient state) (4.) Type of loading (5.) Various boundary conditions (conductive or heat flux boundary) (6.) Effect of creep inclusion.

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