Unified creep-plasticity constitutive equations for 2-1/4 Cr-1 Mo steel at elevated temperature

Robinson, D. N.; Swindeman, R.W.

doi:10.2172/708802

Cited by 30 publications

(15 citation statements)

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“…One of the internal state variable in the Robinson's model (Robinson and Swindeman, 1982) is the internal deviatoric stress or backstress a ij which accounts for the kinematic hardening. According to the Robinson's model, the growth law governing the evolution of internal state variable a ij is given by:…”

Section: Robinson's Viscoplastic Modelmentioning

confidence: 99%

“…Thus, it is concluded that many practical problems, which involve complex geometries as well as complex thermomechanical loading histories such as those arising in hot gaspath components of gas turbine engines and rocket engines, have to be solved in the environment of such numerical solution methodologies which could make these viscoplastic models adaptable for realistic structural and life analyses of this kind of structural components. Some of these numerous viscoplastic models have been proposed by Hart (1970), Hart et al (1976), Robinson and Swindeman (1982), Chan et al (1988) and Chaboche (1986) and have been tested for uniaxial time varying loading on various metals and alloys and the correlation between theory and experiment has generally been found to be very good and shown to faithfully represent experimentally observed material behavior in a variety of applications. Mukherjee (1977Mukherjee ( , 1979, , Morjaria et al ( , 1980c, Morjaria and Mukherjee (1981), Arya (1989Arya ( , 1990, Arya and Kaufman (1989) and Arya and Arnold (1992) presented boundary element methodologies (BEM) and finite element methodologies (FEM) for the solution of boundary value problems with material behavior governed by Hart's and Robinson's constitutive viscoplastic models, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Viscoplastic D/BEM analysis of metallic structures with dependence on thermomechanical history

Providakis

Kourtakis

2002

Engineering Computations

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The feasibility of advanced viscoplastic models for non-linear boundary element analysis of metallic structural components with dependence on thermomechanical history is investigated.Several numerical examples are presented using the boundary element implementation of two different internal state variable viscoplastic models to the solution of time-dependent inelastic problems arising in creeping metallic structural components under the combined action of high temperature loading gradients and quasi-static mechanical loading conditions. To demonstrate the efficiency of the implemented viscoplastic models, the results obtained using the direct boundary element methodology are compared with those obtained by both analytical and finite element solution as well as, for different numerical results of plane strain thermoviscoplastic deformation problems under general thermomechanical loading. IntroductionRecently a number of stress-strain constitutive models known as viscoplastic models have emerged. This is due to the effort to improve the high-temperature performance of structural components used in aerospace and nuclear industry. Inelasticity does not occur in these components as a result of mechanical loading but is induced mainly through thermal transient cycles and thermal gradients. The conventional constitutive equations and damage models fail to reflect the strong thermomechanical path dependence observed in, for example, the cyclic hardening behavior of some metals and alloys especially in the presence of metallurgical changes. So that the development of some realistic viscoplastic models accompanied by appropriate constitutive equations was crucial for the design of high-temperature energy system components. The motivation of these viscoplastic models was the treatment of all the inelastic strains (plastic, creep, relaxation, etc.) as a single quantity and this automatically includes any interaction among them. These viscoplastic models are intended to provide reliable derivation of this high-temperature,

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Section: Robinson's Viscoplastic Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Viscoplastic D/BEM analysis of metallic structures with dependence on thermomechanical history

Providakis

Kourtakis

2002

Engineering Computations

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“…Following Einstein's summation convention, the repeated subscripts in Equation (2) and elsewhere imply summation. The deviatoric stress Sij has the expression (3) With the back stress denoted by Bij, the effective stress I:ii is defined as I:ij = sij-Bij (4) The constitutive equations of the model are now given. …”

Section: Freed's Viscoplastic Modelmentioning

confidence: 99%

Finite element analysis of structural components by using viscoplastic models with application to a cowl lip problem

Arya

1991

Materials at High Temperatures

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“…The model qualitatively reproduced the hot wall thinning but incorporated the drawback that neither viscous effects nor cyclic hardening effects were taken into account in the material formulation. Improved material models, taking into account creep-plasticity interaction and cyclic hardening mechanisms, became available after the works of [10,11]. These were subsequently applied by Arya and co-workers [1,12] to assess the inelastic deformation of an experimental thrust chamber from [6].…”

Section: Introductionmentioning

confidence: 99%

Life prediction of thermally highly loaded components: modelling the damage process of a rocket combustion chamber hot wall

Schwarz¹,

Schwub

Quering³

et al. 2011

CEAS Space J

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During their operational life-time, actively cooled liners of cryogenic combustion chambers are known to exhibit a characteristic so-called doghouse deformation, pursued by formation of axial cracks. The present work aims at developing a model that quantitatively accounts for this failure mechanism. High-temperature material behaviour is characterised in a test programme and it is shown that stress relaxation, strain rate dependence, isotropic and kinematic hardening as well as material ageing have to be taken into account in the model formulation. From fracture surface analyses of a thrust chamber it is concluded that the failure mode of the hot wall ligament at the tip of the doghouse is related to ductile rupture. A material model is proposed that captures all stated effects. Basing on the concept of continuum damage mechanics, the model is further extended to incorporate softening effects due to material degradation. The model is assessed on experimental data and quantitative agreement is established for all tests available. A 3D finite element thermo-mechanical analysis is performed on a representative thrust chamber applying the developed material-damage model. The simulation successfully captures the observed accrued thinning of the hot wall and quantitatively reproduces the doghouse deformation.

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Unified creep-plasticity constitutive equations for 2-1/4 Cr-1 Mo steel at elevated temperature

Cited by 30 publications

References 0 publications

Viscoplastic D/BEM analysis of metallic structures with dependence on thermomechanical history

Viscoplastic D/BEM analysis of metallic structures with dependence on thermomechanical history

Finite element analysis of structural components by using viscoplastic models with application to a cowl lip problem

Life prediction of thermally highly loaded components: modelling the damage process of a rocket combustion chamber hot wall

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