Stress analysis for steady creep

Three-point bending creep tests using miniaturized specimen are proposed to assess creep constitutive properties of materials. Based on Norton's creep law, the analytical model for the three-point bending specimen is given. Through the analytical model, creep parameters can be obtained by regressing the bending test data. Maximum stress approach and reference stress approach are used to convert bending test data to equivalent uniaxial tensile test data. In order to verify these approaches, both three-point bending and uniaxial creep tests of 23CrMoNiWV88 steel are performed. The results show that the derived creep parameters from the bending test data are in reasonable agreement with those obtained from conventional uniaxial creep tests. The equivalent uniaxial creep data converted using reference stress approach are more reasonable than that using maximum stress approach. It has also been found that the large deformation may have a significant influence on the conversion relationship. The results are only accurate at relatively low load levels during testing.

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“…The maximum creep stress is evidently at y = h on the outside fiber, which can be obtained from equation (5). 29 Therefore…”

Section: Analytical Model Of Tpb Creep Testmentioning

confidence: 98%

Assessment of creep constitutive properties from three-point bending creep test with miniaturized specimens

Zhuang

Zhou

et al. 2014

The Journal of Strain Analysis for Engineering Design

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“…So far, several models have been introduced for these functions; the detailed description of these models can be found in Boyle and Spence. 40 In this paper, a nonlinear power law’s creep model of Norton–Bailey (equation (3)) is used to predict the creep behavior of the epoxy. This is a flexible model which can fit the creep strain, as the primary creep behavior is dominant.…”

Section: Theoretical Approachmentioning

confidence: 99%

A new theoretical creep model of an epoxy-graphene composite based on experimental investigation: effect of graphene content

Khabaz-Aghdam

Behjat

Silva

et al. 2020

Journal of Composite Materials

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In this paper, the creep behavior of an epoxy-based adhesive reinforced with different weight fractions of graphene up to 0.5 wt% was studied. Creep tests were performed in three stress levels, using the ultimate strength of the neat epoxy as a reference. Results indicated that the presence of graphene up to 0.5 wt% reduces the creep strain and strain rate of the epoxy. However, the dominant behavior in the creep of epoxy–graphene composites is the creep pattern of the neat epoxy. These experimental observations led to development of theoretical creep models to an appropriate creep model for graphene-reinforced composites by introducing a new function of the graphene weight ratio. A scanning electron microscopy analysis indicated that the strong bond between the graphene surface and epoxy matrix limits the mobility of the molecular chains of the neat epoxy and therefore reduces the creep strain.

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“…Introducing the following abbreviation the constitutive model (20) reduces to Equations (22) can be integrated with respect to the slow time variable providing the mean backstress and the mean creep strain. The numerical solution can be performed by standard time integration techniques developed for creep problems, for example, explicit Euler or Runge–Kutta methods 43 and does not require advanced cycle-by-cycle time step algorithms or cycle jumping techniques. For several loading cases, analytical solutions can be derived illustrating cycle-by-cycle evolution of mean inelastic strains.…”

Section: Analysis Of Cyclic Creepmentioning

confidence: 99%

Two-time-scales and time-averaging approaches for the analysis of cyclic creep based on Armstrong–Frederick type constitutive model

Altenbach

Breslavsky

Naumenko

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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The aim of this paper is the analysis of inelastic behavior under periodic cyclic loading regimes for materials showing recovery effects. Starting with the Armstrong–Frederick type model and applying the two-time-scale asymptotic technique, the constitutive equation for the mean inelastic strain rate and the evolution equation for the mean backstress variable are derived. The advantage of the presented technique is the closed analytical form of the solutions such that the influence of the loading profiles on the resulting slow cycle-by-cycle strain accumulation can be analyzed explicitly. To validate the derived equations, the original constitutive model is integrated numerically by applying the time-step procedure for various cyclic loading profiles. Numerical examples are presented to illustrate cyclic creep behavior of X20CrMoV12-1 heat resistant steel.

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Stress analysis for steady creep

Cited by 27 publications

References 6 publications

Assessment of creep constitutive properties from three-point bending creep test with miniaturized specimens

Assessment of creep constitutive properties from three-point bending creep test with miniaturized specimens

A new theoretical creep model of an epoxy-graphene composite based on experimental investigation: effect of graphene content

Two-time-scales and time-averaging approaches for the analysis of cyclic creep based on Armstrong–Frederick type constitutive model

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