Modelling low-cycle fatigue tests using a gradient-enhanced continuum damage model

Mattos, H.S. da Costa

doi:10.1177/1056789516653244

Cited by 7 publications

(7 citation statements)

References 37 publications

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“…Models can be either empirical or internal-state-variable based formulations. Among the various formulations, continuum damage models have been extensively employed for the description of creep (Wang et al., 2020), fatigue (Da Costa Mattos, 2017; Mareau and Morel, 2019), creep–fatigue interaction (Guo et al., 2020; Wang and Liu, 2019) and fretting-fatigue (Sun et al., 2017) behaviour of wide range of materials used in engineering applications. In the present study, the influence of three different nitrogen contents on the creep deformation and damage creep behaviour of type 316L SS has been investigated in the framework of widely accepted continuum damage mechanics based Kachanov–Rabotnov model (Kachanov, 1960; Rabotnov, 1969).…”

Section: Introductionmentioning

confidence: 99%

Influence of varying nitrogen on creep deformation and damage behaviour of type 316L in the framework of continuum damage mechanics approach

Christopher

Praveen

Ganesan

et al. 2020

International Journal of Damage Mechanics

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In the present study, Kachanov–Rabotnov continuum damage model has been employed to describe the steady state and tertiary creep deformation and damage behaviour of 316L austenitic stainless steel with different nitrogen contents of 0.07, 0.11 and 0.22 wt%, at 923 K. For all the nitrogen contents, the model appropriately predicts the creep strain–time data, creep rupture strain and rupture life. The model parameters such as characteristic strain and damage rates systematically decrease with the increase in nitrogen content. The derived iso-damage contours superimposed on creep strain–time data indicate that the evolution kinetics of strain, as well as damage, are unique at each applied stress level. For nitrogen added type 316L SS, the critical damage value ( ωcr) at which creep failure takes place is found to be less than 1 and is in the range of 0.35–0.60. It is observed that the dominance of damage rate ([Formula: see text]) over the strain rate ([Formula: see text]) increases with increasing nitrogen content from 0.07 to 0.22% N for the steel. A direct correlation has been established between the creep rupture ductility and the ratio of strain rate to damage rate, i.e. [Formula: see text]/[Formula: see text] using the Kachanov–Rabotnov model for different nitrogen contents and stress levels.

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Section: Introductionmentioning

confidence: 99%

Influence of varying nitrogen on creep deformation and damage behaviour of type 316L in the framework of continuum damage mechanics approach

Christopher

Praveen

Ganesan

et al. 2020

International Journal of Damage Mechanics

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“…To obtain the numerical solution for the unknowns Δp and Δr, one can consider Equations ( 38) and (40) as two coupled equations . In the sequel, the local residuals are defined by…”

Section: Return Mapping Algorithmmentioning

confidence: 99%

“…In general, a similar profile of the actual stress with respect to the strain is obtained in Figure 3 compared to the result of Da Costa Mattos. 40 According to the examination of the two important parameters  and 𝜂 cr of the softening function in Equation (35), expected simulation results are obtained. Hence, the present model is capable of capturing an expected fatigue damage behavior for material failure.…”

Section: A Cube With Uniaxial Loadingmentioning

confidence: 99%

Thermomechanical fatigue life prediction of metallic materials by a gradient‐enhanced viscoplastic damage approach

Yin

Zreid

Zhao

et al. 2022

Numerical Meth Engineering

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Fatigue failure plays an important role in engineering applications, especially when structural components experience significant cyclic thermal loading and complex force loading simultaneously. During the last decades, several post-processing techniques have been developed based on empirical investigations of experimental evidence to predict the fatigue life of materials. The work at hand postulates a conventional continuum damage theory for thermomechanical fatigue failure modeling. In particular, an implicit gradient-enhanced approach is employed to address the ill-posedness of the partial differential equation system when the damage onsets. An internal fatigue variable is phenomenologically defined based on the accumulation of viscoplasticity. In the sequel, a regularized fatigue variable is obtained to further yield the damage softening function, which straightforwardly applies to the stress, material tangent, and viscoplastic dissipation. A multi-field problem, consisting of the strain field, the temperature, and the non-local variable, is taken into consideration, leading to a fully coupled system. This numerical methodology is consistently derived and implemented into the context of the finite element method. Several representative and demonstrative examples are performed, which yield good numerical stability and agreement with experimental data. Conclusive findings and further perspectives close this article.

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“…Experimental results show that the steel exhibits obvious ratcheting behaviors and cyclic softening characteristic from 25 to 250 °C, and in the range of 250 °C to 350 °C dynamic strain aging effect was observed. Da Costa Mattos et al [8] have investigated the modeling of low-cycle fatigue tests by using a gradientenhanced continuum damage model. This model considers for the coupling between plasticity and damage, including a mathematically consistent description of the softening behavior and size dependency.…”

Section: Introductionmentioning

confidence: 99%

The ratcheting behavior of carbon steel piping elbows under cyclic bending moment and temperature

Zakavi

Aghaei

2020

J Braz. Soc. Mech. Sci. Eng.

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In this paper, the effect of temperature and out-of-plane dynamic moments on ratcheting behavior of pressurized elbows have been investigated. The combined hardening model (Chaboche kinematic hardening model with isotropic hardening rule) is used for the plastic analysis of materials. Piping elbow specimens had temperatures of 50, 100, 150 and 200 °C. By using of many tension-compression-stabilized tests of specimens under symmetric strain-controlled, constant parameters for materials are obtained. The results obtained by the FE method of specimens show that the deformations occurred mainly because of creep at high temperature and ratcheting strain by out-of-plane moments. Also, ratcheting rate increases by increasing moment bending and temperatures. Initial, strain accumulation rate is low, and it increases with the increasing temperatures, which express softening phenomenon due to thermal creep. The strain accumulation is highest along the hoop direction at flanks, similar to results from experimental data without considering temperature effects. The results show that the increase in ratcheting due to high temperature may lead to incontrollable damages to pipework structures. Of course, the prediction of strain accumulation is improved in the presence of isotropic hardening rule. Keywords Ratcheting • Elbow pipe • Out-of-plane bending moment • Temperature • Strain hardening List of symbols b, Q ∞ Materials constants for isotropic hardening 0 Yield stress at zero plastic strain p Plastic stress tensor p

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Modelling low-cycle fatigue tests using a gradient-enhanced continuum damage model

Cited by 7 publications

References 37 publications

Influence of varying nitrogen on creep deformation and damage behaviour of type 316L in the framework of continuum damage mechanics approach

Influence of varying nitrogen on creep deformation and damage behaviour of type 316L in the framework of continuum damage mechanics approach

Thermomechanical fatigue life prediction of metallic materials by a gradient‐enhanced viscoplastic damage approach

The ratcheting behavior of carbon steel piping elbows under cyclic bending moment and temperature

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