Shake-Down Analysis for Perfectly Plastic and Kinematic Hardening Materials

1993 ◽  
pp. 175-244 ◽  
Author(s):  
E. Stein ◽  
G. Zhang ◽  
R. Mahnken
Keyword(s):  
Kinematic Hardening ◽  
Perfectly Plastic

Shakedown Limit Load Determination for a Kinematically Hardening 90-Degree Pipe Bend Subjected to Constant Internal Pressure and Cyclic Bending

2007 ◽  
Author(s):  
Hany F. Abdalla ◽  
Mohammad M. Megahed ◽  
Maher Y. A. Younan
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Limit Load ◽  
Material Behavior ◽  
Pipe Bend ◽  
Cyclic Bending ◽  
Perfectly Plastic ◽  
Shakedown Limit

A simplified technique for determining the shakedown limit load of a structure employing an elastic-perfectly-plastic material behavior was previously developed and successfully applied to a long radius 90-degree pipe bend. The pipe bend is subjected to constant internal pressure and cyclic bending. The cyclic bending includes three different loading patterns namely; in-plane closing, in-plane opening, and out-of-plane bending moment loadings. The simplified technique utilizes the finite element method and employs small displacement formulation to determine the shakedown limit load without performing lengthy time consuming full cyclic loading finite element simulations or conventional iterative elastic techniques. In the present paper, the simplified technique is further modified to handle structures employing elastic-plastic material behavior following the kinematic hardening rule. The shakedown limit load is determined through the calculation of residual stresses developed within the pipe bend structure accounting for the back stresses, determined from the kinematic hardening shift tensor, responsible for the translation of the yield surface. The outcomes of the simplified technique showed very good correlation with the results of full elastic-plastic cyclic loading finite element simulations. The shakedown limit moments output by the simplified technique are used to generate shakedown diagrams of the pipe bend for a spectrum of constant internal pressure magnitudes. The generated shakedown diagrams are compared with the ones previously generated employing an elastic-perfectly-plastic material behavior. These indicated conservative shakedown limit moments compared to the ones employing the kinematic hardening rule.

Plastic Collapse of Steep Conical Shells under Axial Compression

1972 ◽  
Vol 1 (3) ◽  
pp. 121-128 ◽  
Author(s):  
H. Ramsey
Keyword(s):  
Axial Compression ◽  
Kinematic Hardening ◽  
Yield Condition ◽  
Experimental Results ◽  
Plastic Collapse ◽  
Conical Shells ◽  
Plastic Behaviour ◽  
Perfectly Plastic ◽  
Collapse Mode ◽  
Axisymmetric Plastic

Analysis and experimental results are presented for two axisymmetric plastic collapse modes in steep, truncated conical shells under axial compression. The two collapse modes are strongly dependent on cone height and the boundary conditions. One collapse mode, which consists of flaring of the large end of the cone, can be analyzed satisfactorily on the basis of rigid-perfectly plastic behaviour. The Tresca sandwich-shell yield condition is used and close agreement is obtained with the experimental results. The other collapse mode is a local bulging of the small end. It is shown in the analysis that perfectly plastic behaviour cannot account for this collapse mode. Consideration of kinematic-hardening leads to a pseudo-elastic analysis of a uniform shell. The observed deformation is found to be due to buckling of the Shanley type. Rayleigh’s method is employed to obtain an estimate of a length parameter which characterizes the critical condition for buckling. Agreement with the experimental results is not very satisfactory, probably because a constant value for the tangent modulus was assumed.

Evaluating the Effect of Buckling-Restrained Brace Model on Seismic Structural Responses

2017 ◽  
Vol 11 (02) ◽  
pp. 1750002 ◽  
Author(s):  
Yulong Feng ◽  
Jing Wu ◽  
Chunlin Wang ◽  
Shaoping Meng
Keyword(s):  
Kinematic Hardening ◽  
Stiffness Ratio ◽  
Braced Frames ◽  
Simplified Models ◽  
Buckling Restrained Brace ◽  
Perfectly Plastic ◽  
Seismic Design Code ◽  
Structural Responses ◽  
Buckling Restrained Braced Frames ◽  
Elastic Perfectly Plastic

Numerical simulation is an important measure to study the seismic performance of buckling-restrained braced frames (BRBFs). Practically, some simplified models, such as the elastic–plastic with kinematic hardening model and the elastic perfectly-plastic model, are used to simulate the behavior of buckling-restrained brace (BRBs). To provide structural engineers the reference of errors when simplified models are used, this paper comparatively evaluates the effect of the BRB model on seismic structural responses using the OpenSees software. A comparison is made on six-storey and 16-storey BRBFs with rigid beam-to-column connections; these are designed according to Chinese seismic design code. Moreover, the effects of the post-yielding stiffness ratio of frame [Formula: see text] and the stiffness ratio of BRB to frame [Formula: see text] on the errors are specifically investigated through a parametric study of both BRBFs. The results show that the seismic response average errors of the simplified models are mostly less than 5%, which satisfies the engineering requirements.

An Assessment of Kinematic Hardening Thermal Ratcheting

1974 ◽  
Vol 96 (3) ◽  
pp. 214-221 ◽  
Author(s):  
T. M. Mulcahy
Keyword(s):  
Thermal Loading ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Strain Accumulation ◽  
Hardening Material ◽  
Perfectly Plastic ◽  
Thermal Ratcheting

Analytical comparisons are made between the thermal ratcheting response of a kinematic hardening material, a perfectly plastic, and an isotropic hardening material for a two-element assembly. Significant differences were found in the range of mechanical and thermal loading for which ratcheting occurred and the magnitude of the strain accumulation when ratcheting did occur. The kinematic hardening strain accumulation predicted was always smallest.

An Improved Thermo-Ratcheting Boundary of Pressure Pipeline

2016 ◽  
Vol 725 ◽  
pp. 311-315
Author(s):  
Qian Hua Kan ◽  
Jian Li ◽  
Han Jiang ◽  
Guo Zheng Kang
Keyword(s):  
Mechanical Stress ◽  
Nuclear Power ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Plastic Strain Increment ◽  
Perfectly Plastic ◽  
Axial Tensile ◽  
Thermal Ratcheting ◽  
Pressure Pipeline ◽  
Elastic Perfectly Plastic

The thermal ratcheting boundary of pressure pipeline is a popular topic in nuclear power engineering. The existed thermal ratcheting boundary based on the Bree diagram is conservative for structures subjected to the thermo-mechanically coupled loadings since it was obtained only from an elastic-perfectly plastic model. Therefore, it is necessary to improve the existed thermal ratcheting boundary based on a reasonable constitutive model. The Bree diagram was validated firstly by the linear relationship between the plastic strain increment and mechanical stress by finite element method. And then the influences of different constitutive models, such as elastic-perfectly plastic, multi-linear kinematic hardening, Chaboche and Abdel Karim-Ohno models, on the thermal ratcheting boundary of pressure pipeline were investigated numerically. It is found that the elastic-perfectly plastic and multi-linear kinematic hardening models provide the lower and upper bounds for the thermal ratcheting boundary, respectively. Finally, an improved thermal ratcheting boundary by introducing the dimensionless axial tensile stress was proposed based on the Bree diagram, the improved thermal ratcheting boundary covered the present cases with different ratios of mechanical stress over thermal stress.

Some Achievements of the European Project LISA for FEM Based Limit and Shakedown Analysis

2002 ◽  
Author(s):  
M. Staat
Keyword(s):  
Large Scale ◽  
Optimization Problems ◽  
Kinematic Hardening ◽  
Plastic Limit ◽  
Limit States ◽  
Surface Plasticity ◽  
Perfectly Plastic ◽  
Large Scale Analysis ◽  
Load Carrying ◽  
Element Discretizations

The load-carrying capacity or the safety against plastic limit states are central questions in the design of pressure equipment. The new European standard prEN 13445-3 reflects the fact that plastic limit states can be calculated simply by perfectly plastic limit and shakedown analyses. These methods can be derived from static and kinematic theorems for lower and upper bound analysis, respectively. Both may be formulated as optimization problems for finite element discretizations of structures. The problems of large-scale analysis have been solved in an European research project. The methods could be made more realistic by extension to other material models such as a two-surface plasticity model of kinematic hardening. Limit and shakedown analyses are briefly demonstrated with illustrative examples, which are chosen to show some limitations of the 3Sm criterion and the effect of kinematic hardening.

Elasto-Plastic Finite Element Analyses of Two-Dimensional Rolling and Sliding Contact Deformation of Bearing Steel

1989 ◽  
Vol 111 (2) ◽  
pp. 309-314 ◽  
Author(s):  
A. M. Kumar ◽  
G. T. Hahn ◽  
V. Bhargava ◽  
C. Rubin
Keyword(s):  
Finite Element ◽  
Rail Steel ◽  
Kinematic Hardening ◽  
High Hardness ◽  
High Strength ◽  
Bearing Steel ◽  
Sliding Contact ◽  
Plastic Behavior ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

In the past, the mechanics of repeated rolling and sliding contact could only be treated for the idealized, elastic-perfectly-plastic (and isotropic) cyclic materials behavior, albeit approximately. They have not proven useful because the real cyclic plastic behavior of contacting materials is anything but perfectly plastic or isotropic. Using finite element methods, the authors have developed techniques for treating elastic-linear-kinematic hardening-plastic (ELKP) behavior, an idealization that comes much closer to the behavior of low, medium, and high hardness steels. In an earlier paper, the authors have examined rolling and sliding on rail steel, which is much softer than hardened bearing steel and displays quite different ELKP properties. The present paper offers the first results for repeated rolling and sliding for high strength bearing steel ELKP behavior and material properties.

Finite Element Based Unloading of an Elastic Plastic Spherical Stick Contact for Varying Tangent Modulus and Hardening Rule

2013 ◽  
Vol 1 (1) ◽  
pp. 13-32
Author(s):  
Biplab Chatterjee ◽  
Prasanta Sahoo
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Tangent Modulus ◽  
Isotropic Hardening ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Hardening Models ◽  
Qualitative Similarity ◽  
Elastic Perfectly Plastic

Loading-unloading behavior of a deformable sphere with a rigid flat under full stick contact condition is investigated for varying strain hardening. The study considers various tangent modulus using the finite element software ANSYS. Both the bilinear kinematic hardening and isotropic hardening models are considered. Numerical simulation reveals the qualitative similarity between kinematic and isotropic hardening regarding the variation of interfacial parameters during loading-unloading for various tangent modulus. It is found that the material with kinematic hardening dissipates more energy than the material with isotropic hardening during unloading. However for elastic perfectly plastic material, the loading-unloading behavior is insensitive to hardening model.

Elastoplastic Finite Element Analysis of Three-Dimensional, Pure Rolling Contact at the Shakedown Limit

1990 ◽  
Vol 57 (1) ◽  
pp. 57-65 ◽  
Author(s):  
S. M. Kulkarni ◽  
G. T. Hahn ◽  
C. A. Rubin ◽  
V. Bhargava
Keyword(s):  
Finite Element ◽  
Half Space ◽  
Kinematic Hardening ◽  
Three Dimensional ◽  
Element Model ◽  
Rolling Contact ◽  
Stress Strain ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Shakedown Limit

This paper describes a three-dimensional elastoplastic finite element model of repeated, frictionless rolling contact. The model treats a sphere rolling on an elastic-perfectly plastic and an elastic-linear-kinematic-hardening plastic, semi-infinite half space. The calculations are for a relative peak pressure (po/k) = 4.68 (the theoretical shakedown limit for perfect plasticity). Three-dimensional rolling contact is simulated by repeatedly translating a hemispherical (Hertzian) pressure distribution across an elastoplastic semi-infinite half space. The semi-infinite half space is represented by a finite mesh with elastic boundaries. The calculations describe the distortion of the rim, the residual stress-strain distributions, stress-strain histories, and the cyclic plastic strain ranges in the vicinity of the contact.

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