Non-cyclic shakedown/ratcheting boundary determination - Part 2: Numerical implementation

Adibi-Asl, R.; Reinhardt, Wolf

doi:10.1016/j.ijpvp.2011.06.007

Cited by 23 publications

(11 citation statements)

References 11 publications

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“…176,177 The proposed method divided the loading into the mean time invariant and completely reverse loading and determined shakedown-ratcheting boundary without employing cyclic history. 176,177 The proposed method divided the loading into the mean time invariant and completely reverse loading and determined shakedown-ratcheting boundary without employing cyclic history.…”

Section: A-r Methodsmentioning

confidence: 99%

“…The loading threshold is designed to achieve safe structural response as shakedown theorems are employed within safety domain of specified loads. Of the LMM category, several other methods including the lower bound noncyclic, 176,177 the hybrid 182 constituent method with Rolls Royce's hierarchical FE framework, and the RSD 179 enabling to decompose the residual stresses over steady loading cycles were emerged. This numerical approach was accompanied with an automated search algorithm enabling several trial-error iterations to determine the plastic shakedown 253 through a hierarchical FE framework.…”

Section: Ratcheting Analysis By Means Of Numerical Methodsmentioning

confidence: 99%

“…The lower bound formulation in shakedown on the basis of Melan's theorem was further developed by researchers. 176,177 The proposed method divided the loading into the mean time invariant and completely reverse loading and determined shakedown-ratcheting boundary without employing cyclic history. They employed the model along with Bree's diagram for an elbow under constant pressure and cyclic loads.…”

Section: A-r Methodsmentioning

confidence: 99%

“…The method ensured both equilibrium and compatibility at each stage of analysis. Of the LMM category, several other methods including the lower bound noncyclic, 176,177 the hybrid 182 constituent method with Rolls Royce's hierarchical FE framework, and the RSD 179 enabling to decompose the residual stresses over steady loading cycles were emerged. The Hybrid method 182,258 was implemented in the form of a lower bound ratchet analysis method by Jappy et al 182,259 They developed a strategy to evaluate ratcheting boundary through an implicit, lower bound, and multiaxial solution.…”

Section: Ratcheting Analysis By Means Of Numerical Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Ratcheting in pressurized pipes and equipment: A review on affecting parameters, modelling, safety codes, and challenges

Varvani‐Farahani

Nayebi

2018

Fatigue Fract Eng Mat Struct

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The current study has attempted to comprehensively review ratcheting response of materials involving various influential parameters such as loading spectra, thermal cycles, stress levels, stress raisers, strain rate, and visco‐plasticity and material types with a focus on pressurized pipes and equipment. The mechanism of deformation, types, and the rate of progress over stages of ratcheting were discussed. Safety design codes and procedures were highlighted for reliable design of pressurized pipes against progressive ratcheting and to safeguard the system against catastrophic failure at which both mechanical and thermal ratcheting were integrated. Boundaries and demarcation of ratcheting‐shakedown zones developed based on Bree's diagram were employed to assess plastic deformation accumulation over stress cycles. Shakedown and ratcheting boundaries were discussed through methods developed on the basis of Melan's theorem over last few decades. Ratcheting response of materials was reviewed through descriptions of parametric models and kinematic hardening rules involving various variables and parameters. Interaction of ratcheting with creep and low‐cycle fatigue has promoted progressive damage in materials. Pressurized pipes subjected to thermal cycles and external bending cycles were evaluated by numerical solutions along with kinematic hardening rules to assess ratcheting over stress cycles.

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Section: A-r Methodsmentioning

confidence: 99%

Section: Ratcheting Analysis By Means Of Numerical Methodsmentioning

confidence: 99%

Section: A-r Methodsmentioning

confidence: 99%

Section: Ratcheting Analysis By Means Of Numerical Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Ratcheting in pressurized pipes and equipment: A review on affecting parameters, modelling, safety codes, and challenges

Varvani‐Farahani

Nayebi

2018

Fatigue Fract Eng Mat Struct

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“…Adibi-Asl and Reinhardt raised a non-cyclic method for shakedown analysis employing a combination of linear and nonlinear FEA [4,5]. Abdalla et al proposed a simplified technique to predict the ratcheting boundary of elbow piping [6].…”

Section: Introductionmentioning

confidence: 99%

Cyclic plasticity behaviors of steam turbine rotor subjected to cyclic thermal and mechanical loads

Zhu

Chen²,

Xuan

et al. 2017

European Journal of Mechanics - A/Solids

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This version is available at https://strathprints.strath.ac.uk/61706/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the AbstractIn this paper, shakedown and ratchet analyses are performed to investigate the cyclic plasticity behaviors of the steam turbine rotor subjected to cyclic thermal and mechanical loads by employing Linear Matching Method (LMM). Traditionally, the shakedown or ratchet analysis mainly focus on the structure under general cyclic loading condition composed by constant mechanical load and cyclic thermal load, but the investigated steam turbine rotor here is subjected to cyclic mechanical load and cyclic thermal load that vary in phase and out of phase throughout the practical operation load cycle.The failure behaviours of structure under practical operation load cycle is studied and discussed. The novel shakedown and ratchet failure diagrams are plotted by calculating different combinations of cyclic mechanical load and cyclic thermal load. The innovative equation to acquire plastic strain range of the structure under steady state cycle is fitted, which is vital for low cycle fatigue (LCT) assessment.Moreover, detailed step-by-step inelastic analyses are also performed to verify the applicability and effectiveness of the limit boundaries calculated by the LMM. All the investigations demonstrate that the proposed LMM technique is capable of handling practical industrial application with complicated cyclic loads.

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A generalised method for ratchet analysis of structures undergoing arbitrary thermo‐mechanical load histories

Lytwyn

Chen

Ponter

2015

Numerical Meth Engineering

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This version is available at https://strathprints.strath.ac.uk/52828/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the University of Leicester, Leicester, LE1 7RH, UK AbstractA novel approach is presented based upon the Linear Matching Method framework in order to directly calculate the ratchet limit of structures subjected to arbitrary thermo-mechanical load histories. Traditionally, ratchet analysis methods have been based upon the fundamental premise of decomposing the cyclic load history into cyclic and constant components respectively, in order to assess the magnitude of additional constant loading a structure may accommodate before ratcheting occurs. The method proposed in this paper, for the first time, accurately and efficiently calculates the ratchet limit with respect to a proportional variation between the cyclic primary and secondary loads, as opposed to an additional primary load only. The method is a strain based approach and utilises a novel convergence scheme in order to calculate an approximate ratchet boundary based upon a predefined target magnitude of ratchet strain per cycle. The ratcheting failure mechanism evaluated by the method leads to less conservative ratchet boundaries compared to the traditional Bree solution. The method yields the total and plastic strain ranges as well as the ratchet strains for various levels of loading between the ratchet and limit load boundaries. Two example problems have been utilised in order to verify the proposed methodology.

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Non-cyclic shakedown/ratcheting boundary determination - Part 2: Numerical implementation

Cited by 23 publications

References 11 publications

Ratcheting in pressurized pipes and equipment: A review on affecting parameters, modelling, safety codes, and challenges

Ratcheting in pressurized pipes and equipment: A review on affecting parameters, modelling, safety codes, and challenges

Cyclic plasticity behaviors of steam turbine rotor subjected to cyclic thermal and mechanical loads

A generalised method for ratchet analysis of structures undergoing arbitrary thermo‐mechanical load histories

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