Estimation of Creep Failure Life of Rotor Grade Steel by Using Time–Temperature Parametric Methods

Mehta, Manish; Kashyap, B.P.; Singh, Rajeev Kumar; Kadam, Ruthvik; Bapat, Sachin

doi:10.1007/s12666-015-0755-x

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…Boundary conditions are obtained from symmetry conditions and constraint in radial (z 1 ) direction. Analysis of convergence of obtained results depending on number of unknowns in finite element model has been carried out using comparison of distribution of dimensionless stress intensity [10] for meshes with 1074, 3344, and 9596 unknowns. Inaccuracy of stresses determination under elastic deformation reaches around 2%.…”

Section: Results Of Finite Element Modeling Of Continual Fracture Andmentioning

confidence: 99%

Finite Element Analysis of Influence of Non-homogenous Temperature Field on Designed Lifetime of Spatial Structural Elements under Creep Conditions

Pyskunov

Maksimyk

Валер

2016

Applied Mathematics and Nonlinear Sciences

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The techniques of modeling of continual fracture process for spatial bodies under long-term static force loading condition in non-homogenous temperature field are presented. The scalar damage parameter is used to describe the material continual fracture process. A stress-strain problem solution made with semianalytic finite element method (SFEM). Results of lifetime determination of responsible parts are presented.

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Section: Results Of Finite Element Modeling Of Continual Fracture Andmentioning

confidence: 99%

Finite Element Analysis of Influence of Non-homogenous Temperature Field on Designed Lifetime of Spatial Structural Elements under Creep Conditions

Pyskunov

Maksimyk

Валер

2016

Applied Mathematics and Nonlinear Sciences

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“…The crazing mechanism is mainly divided into craze initiation, craze growth and craze failure (Mehta et al, 2016;Courtenry, 2005;Thomas et al, 2007;Hui et al, 1992;Bucknall, 2007;Mariseen, 2000;De Focatiis and Paul Buckley, 2008;Argon, 2011;Kramer, 1983;Donald and Kramer, 1981): Craze initiation starts by extension of the chain coils and pulling them from the bulk material, giving rise to fibrils bridging. The large contrast between inter-chain and strong intra-chain is the main reason for the currency of this phenomenon (Luo and Liu, 2007;Sokkar et al, 2014;Sokkar and EI-Farahaty, 2016).…”

Section: Morphology Initiation and Growth Of Crazingmentioning

confidence: 99%

Residual life assessment method for polymethyl methacrylate

Wei¹,

Zhao²,

Gao³

et al. 2020

MMMS

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PurposeFatigue and creep are the key factors for the failure of polymethyl methacrylate (PMMA) in the engineering structure, so a great of quantity attention is focused on the life prediction under the creep and fatigue conditions. This paper aims to mainly summarize the traditional life assessment method (S–N curve), life assessment method based on crazing density and life assessment method based on transmittance. S–N curve and classical creep curve are introduced on the traditional life assessment method; the variation of the craze density with the logarithm of cyclic numbers is given in different fatigue load. A linear relationship is obtained, and a higher stress leads to a higher slope, suggesting a faster growth of craze. Furthermore, a craze density model is purposed to describe this relationship; the variation of craze density with the time at different creep load is given. The craze density has two obvious stages. At the first stage, craze density ranged from approximately 0.02 to 0.17, and a linear relationship is obtained. In the following stage, a nonlinear relationship appears till specimen rupture, a new creep life model is proposed to depict two stages. The relationship between transmission and time under creep load is shown. With increasing of time, the transmittance shows a nonlinear decrease. Through polynomial nonlinear fitting, a relationship between the transmittance and residual life can be obtained. To provide reference for the life assessment of transparent materials, the paper compares three life assessment methods of PMMA.Design/methodology/approachThis paper uses the traditional life assessment method (S–N curve), life assessment method based on crazing density, life assessment method based on transmittance.FindingsThe variation of the craze density with the logarithm of cyclic numbers is given in different fatigue loads. A linear relationship is obtained, and a higher stress leads to a higher slope, suggesting a faster growth of craze. Furthermore, a craze density model is proposed to describe this relationship, and the variation of craze density with the time at different creep loads is given. The craze density has two obvious stages. The relationship between transmission and time under creep load is shown. With increasing of time, the transmittance shows a nonlinear decrease. Through polynomial nonlinear fitting, a relationship between the transmittance and residual life can be obtained.Originality/valueFatigue and creep are the key factors for the failure of PMMA in the engineering structure, so a great of quantity attention is focused on the life prediction under the conditions of creep and fatigue. This paper mainly summarizes traditional life assessment method (S–N curve), life assessment method based on crazing density and life assessment method based on transmittance.

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“…The Original Larson-Miller relation is obtained from the Arrhenius relationship (Equation.3) at constant mechanical stress by considering temperature and activation energy [24].…”

Section: Proposed Creep Life Model Considering Humiditymentioning

confidence: 99%

Probabilistic Life Assessment of Gas Turbine Blade Alloys under Creep

Mohammadlou

Pourgolmohamad

Yazdani

2020

IJRRS

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Deformations occur gradually in the gas turbine components since they are working under high temperature and stress. In the turbine blade alloys, creep is the most significant failure mechanism. In this research, creep life has been estimated for the blade alloys by considering humidity. A method is proposed to estimate the creep life by direct consideration of humidity on the creep life of the gas turbine blade. In the proposed model, the humidity factor is added to the classic Larson Miller creep life estimation method. This model is capable of predicting creep life with known dry temperature (Water Air Ratio=0), mechanical stress, and humidity. In this approach, there is no need to measure blade temperature variation during operation. As a case study, the creep life of first-stage turbine blade alloy is predicted using the proposed method and benchmarked with published (Finite element analysis) FEA results. The reliability of the blades was estimated by considering different success criteria using Monte Carlo simulation. The reliability of the creep rupture life of Nimonic-90 steel was carried out using SCRI mode based on the Z-parameter. The scattered data has been considered for creep rupture of materials in this part. The results show that creep life increases with humidity increase. It is also shown that with an increase in mechanical stress and temperature fluctuations, the reliability of the turbine blade creep life decreases sharply.

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Estimation of Creep Failure Life of Rotor Grade Steel by Using Time–Temperature Parametric Methods

Cited by 7 publications

References 4 publications

Finite Element Analysis of Influence of Non-homogenous Temperature Field on Designed Lifetime of Spatial Structural Elements under Creep Conditions

Finite Element Analysis of Influence of Non-homogenous Temperature Field on Designed Lifetime of Spatial Structural Elements under Creep Conditions

Residual life assessment method for polymethyl methacrylate

Probabilistic Life Assessment of Gas Turbine Blade Alloys under Creep

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