A one-parameter nonlinear fatigue damage accumulation model

Pulsating tension tests with constant amplitude (CA) and variable amplitude (VA) were conducted to investigate the interior failure mechanisms of a carburized Cr steel, and a cumulative damage model with the fine granular area (FGA) formation process was proposed in this study. Such a steel represents the continuously descending S‐N (stress‐number of cycles) curve characteristics associated with inclusion‐FGA‐fisheye induced failure even under variable amplitude. Due to crack growth retardations and accelerations resulted from the interaction effect between stepwise resets of the applied stress, the crack morphology under variable amplitude loading is much rougher. The interior failure mechanism was elucidated in combination with the determination of stress intensity factor values at different crack tips. Based on proposed damage model, the agreement between the predicted and experimental results is fairly good within the factor‐of‐two range.

“…That is, Equation can be given by

\frac{\sqrt{{area}_{FGA, n_{i}}}}{\sqrt{{area}_{FGA, N_{i}}}} = {(\frac{n_{i}}{N_{i}})}^{f (();, σ, p)} .

q_{i} = {(\frac{2 σ_{i}}{σ_{normalb}})}^{- 0.75}

q_{i} = {(\frac{2 σ_{i}}{0.8 σ_{s}})}^{- 0.75} .

Therefore, the interior damage process at σ i can be expressed as

\frac{\sqrt{{area}_{FGA, n_{i}}}}{\sqrt{{area}_{FGA, N_{i}}}} = {(\frac{n_{i}}{N_{i}})}^{{((), \frac{2 σ_{i}}{0.8 σ_{normals}})}^{- 0.75}} .

Section: Resultsmentioning

confidence: 99%

Interior induced fatigue of surface‐strengthened steel under constant and variable loading: Failure mechanism and damage modeling

Sun

Gao

et al. 2019

“…However, the linear damage accumulation rule would result in an overestimated fatigue life in the case of HL block loading and a shorter predicted fatigue life in the LH loading path . To overcome this shortcoming, numerous nonlinear cumulative fatigue damage models had been proposed considering the influence of loading history . Fatemi et al and Schijve comprehensively reviewed the accumulative fatigue damage models with detailed discussion on the influencing factors.…”

Section: Introductionmentioning

confidence: 99%

“…[10][11][12] To overcome this shortcoming, numerous nonlinear cumulative fatigue damage models had been proposed considering the influence of loading history. [13][14][15][16][17][18][19] Fatemi et al 10 and Schijve 20 comprehensively reviewed the accumulative fatigue damage models with detailed discussion on the influencing factors. Nonlinear damage accumulation theories are generally categorized as S-N diagram related, 21 crack growth related, 22 continuum damage mechanics related, 23 and strain energy related.…”

Section: Introductionmentioning

confidence: 99%

Residual fatigue life prediction based on a novel damage accumulation model considering loading history

Shi

et al. 2020

The influence of prior low‐cycle fatigue (LCF) on the residual fatigue life was investigated experimentally. A Ni‐based alloy was cyclically loaded under stress‐controlled low‐high (LH) block loading. In the first loading step, low‐amplitude loading was performed with the stress amplitude of 283.5MPa at 710°C. Different cycles of preloading were performed, varying from 100 to 10 000. Subsequently, high‐amplitude fatigue loading was carried out with the stress amplitude of 315MPa at 800°C. Experimental results show that the previous loading was beneficial to the residual fatigue life when the consumed life fraction is below 0.2 and detrimental when the consumed life fraction is larger than 0.2. A novel nonlinear fatigue damage accumulation model was proposed to estimate the residual LCF life under LH loading path considering the effects of load sequence and preloading cycles. The proposed model provided a better life prediction than some existing models, such as Kwofie‐Rahbar model, Miner' rule, Peng model, and Ye‐Wang model. Lastly, this model was further validated using various materials under LH and high‐low block loadings.

“…More specifically, a proposal on generalization of the Kohout‐Věchet model is elaborated for several fatigue damage parameters. Rege et al presented a nonlinear fatigue damage cumulative model with only one parameter included for residual life estimation. Using an S‐N curve under constant amplitude loading, Theil developed a simple fatigue life prediction method by considering the effect of overloading blocks, which provides more accurate estimations than the Miner's rule.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear fatigue damage accumulation and life prediction of metals: A comparative study

Zhu

Hao

Correia

et al. 2018

Fatigue damage modelling and life prediction of engineering components under variable amplitude loadings are critical for ensuring their operational reliability and structural integrity. In this paper, five typical nonlinear fatigue damage accumulation models are evaluated and compared by considering the influence of load sequence and interaction on fatigue life of P355NL1 steels. Moreover, a new nonlinear fatigue damage accumulation model is proposed to account for these two effects. Experimental datasets of pressure vessel steel P355NL1 and four other materials under two‐block loadings are used for model comparative study. Results indicate that the proposed model yields more accurate fatigue life predictions for the five materials than the other models.