Mechanism-Based Evaluation of Thermal Ratcheting due to Traveling Temperature Distribution

Igari, Toshihide; Wada, Hiroshi; Ueta, Masahiro

doi:10.1115/1.556162

Cited by 19 publications

(16 citation statements)

References 12 publications

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“…Igari et al (1990) studied the ratcheting mechanism experimentally, and confirmed the conservative nature of the method proposed by Wada et al The ratcheting strain depends on the traveling range of the temperature distribution, that is, accumulation of the ratcheting strain derived from short range traveling of the temperature distribution saturates at early stage. Igari et al (2000) proposed the mechanism-based evaluation method to evaluate the thermal ratcheting due to the temperature distribution traveling not only long range but also short range. In the "hot-spot model" used in their formulation, the range in which the plastic strain accumulates is equivalent to the traveling range of the temperature distribution.…”

Section: Introductionmentioning

confidence: 99%

A study on plastic strain accumulation caused by traveling of temperature distribution synchronizing with temperature rise

Okajima

2016

Mechanical Engineering Journal

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The prevention of excessive deformation by thermal ratcheting is important in the design of high-temperature components of fast breeder reactors (FBR). This includes evaluation methods for a new type of thermal ratcheting caused by an axial traveling of temperature distribution, which corresponds to moving-up of liquid sodium surface in startup phase. Long range traveling of the axial temperature distribution brings flat plastic deformation profile in wide range. Therefore, at the center of this range, residual stress that brings shakedown behavior does not accumulate. As a result, repeating of this temperature traveling brings continuous accumulation of the plastic strain, even if there is no primary stress. In contrast, in the case with short range traveling, residual stress is caused by constraint against elastic part, and finally it results in shakedown. Because of this mechanism, we supposed that limit for the shakedown behavior depends on distance from the elastic part (i.e. half length of region with plastic deformation). In this paper, we examined characteristics of the accumulation of the plastic strain caused by realistic heat transients, namely, traveling of temperature distribution synchronizing with temperature rise. This examination was based on finite element analyses using elastic-perfectly plastic material. As a result, we confirmed that the shakedown limit depends not on the traveling range of the temperature distribution but the plastic deformation range, which was predicted by the elastic analysis. In the actual application, we can control the plastic deformation range by changing rate of the moving-up of liquid sodium surface.

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Section: Introductionmentioning

confidence: 99%

A study on plastic strain accumulation caused by traveling of temperature distribution synchronizing with temperature rise

Okajima

2016

Mechanical Engineering Journal

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“…To consider the effect of travel distance, Igari et al (2000) proposed the mechanism-based evaluation method. They formulated the accumulated plastic strain and residual stress based on Timoshenko's shell theory (Timoshenko and Krieger, 1959).…”

Section: Formulation Of the Accumulated Plastic Strainmentioning

confidence: 99%

“…To reproduce the hot-spot model used in the formulation by Igari et al (2000) in the validation study, we used (d) Triangle-shaped models. In (e) Double-Ramp-shaped model, temperature distribution expands spatially with time.…”

Section: Validation Of the Proposed Criterion 41 Analyses Conditionsmentioning

confidence: 99%

“…Wada et al (1989Wada et al ( , 1993 proposed an evaluation method for increment in plastic strain due to long distance travel of temperature distribution. Igari et al (2000) proposed an evaluation method that considered the effect of travel distance. In addition, we have proposed and validated a screening criterion for this ratcheting mechanism (Okajima, 2016a(Okajima, , 2016b.…”

Section: Introductionmentioning

confidence: 99%

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Study on a unified criterion for preventing plastic strain accumulation due to long distance travel of temperature distribution

Okajima

Wakai

Kawasaki

2017

Mechanical Engineering Journal

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The prevention of excessive deformation by thermal ratcheting is important in the design of high-temperature components of fast breeder reactors (FBR). In an experimental study that simulated a fast breeder reactor vessel near the coolant surface, it was reported that the long distance travel of temperature distribution causes a new type of thermal ratcheting, even in the absence of primary stress. In this paper, we propose a simple screening criterion to prevent continuous accumulation of plastic strain derived from long distance travel of temperature distribution. The major cause of this ratcheting is the lack of residual stress that brings shakedown behavior at the center of yielding area. Because residual stresses are derived from constraint by the neighboring elastic region, we focused on the distance from the center of yielding area to the elastic region. Accordingly, the proposed criterion restricts the axial length of the full-section yield area, which is the double of the above distance. We validated the proposed criterion based on finite element analyses using an elastic-perfectly plastic material. As a result of the validation analyses, we confirmed that the accumulation of plastic strain saturates before second cycles in the cases satisfying the proposed criterion, regardless of the shape of temperature distribution.

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“…Since ratchetting in austenitic stainless steel structure includes plastic straining with cyclic hardening property, it is essential to involve sophisticated constitutive model to simulate inelastic behaviour such as in Lemaitre and Chaboche (1990), . There are various literatures available on thermal ratchetting for high temperature reactor components as in Chaboche (1994), Chellapandi et al (2000) and Igari et al (2000). Chaboche combined isotropic and kinematic hardening model is implemented in user defined subroutine with semi-implicit integration technique for plasticity calculation.…”

Section: Introductionmentioning

confidence: 99%

Progressive deformation behaviour of thin cylindrical shell under cyclic temperature variation using Combined Hardening Chaboche Model

Mishra

Kumar

Chellapandi

2014

Lat. Am. j. solids struct.

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This study intends to evaluate thermal ratchetting deformation due to cyclic thermal loading along the axis of a smooth cylindrical shell. Two cases of progressive deformation behaviour are discussed for different loading methods. The aim of the first case is to recognize the shakedown behaviour of the cylinder under applied loading cycles. Alternatively, second case is highlighting the ratchetting behaviour of the cylinder. Based on the loading method in second case, a smooth thin hollow cylinder is considered to simulate the progressive deformation. This condition simulates the 1/25 th scale down model of the Prototype Fast Breeder Reactor (PFBR) main vessel.

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Mechanism-Based Evaluation of Thermal Ratcheting due to Traveling Temperature Distribution

Cited by 19 publications

References 12 publications

A study on plastic strain accumulation caused by traveling of temperature distribution synchronizing with temperature rise

A study on plastic strain accumulation caused by traveling of temperature distribution synchronizing with temperature rise

Study on a unified criterion for preventing plastic strain accumulation due to long distance travel of temperature distribution

Progressive deformation behaviour of thin cylindrical shell under cyclic temperature variation using Combined Hardening Chaboche Model

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