Effect of notch geometry on the fatigue strength and critical distance of TC4 titanium alloy

Hu, Xuteng; Xu, Jie; Bao, Zhenqiang; Song, Yang

doi:10.1007/s12206-017-0919-1

Cited by 24 publications

(5 citation statements)

References 21 publications

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“…The notch radius and SCF studies have direct relevance to understand the influence of surface roughness on the fatigue strength of materials. The studies on the effect of surface roughness on fatigue strength of aluminium alloy [25], the relationship between fatigue notch factor and strength [26], and the effect of notch geometry on fatigue strength [27] emphasize the role of theoretical SCF in fatigue analyses. There exists a well-established semi empirical method that relate the theoretical SCF, with the material and geometry dependent fatigue notch factor [6,9].…”

Section: Discussionmentioning

confidence: 99%

Characterising the notch root radii and analyses of stress concentration factors near the dominant valleys of rough surface profiles

Gebrehiwot,

Espinosa-Leal,

Remes

et al. 2023

RakMek

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Surface roughness is one of the key surface integrity factors affecting the strength and fatigue life of components. Stress concentrations occur due to the randomness of the surface profiles. The presence of a dominant valley, a complex geometry and interacting effects exasperate the severity of the stress concentrations. To estimate the theoretical stress concentration factor (SCF) at the valley, the notch root radius should be estimated carefully. We propose an effective method for estimating the root radius of the deepest valley using numerical derivative techniques. The surface roughness of a carefully sanded Alumec 89 block was measured using SJ-400 tester. The 1-D roughness data was used first to evaluate the root radius of the deepest valleys and then, estimate the SCF using analytical and computational methods. We used 2-D finite element (FE) models under uniaxial tension for the computational analyses. The validity of our method is based on determining the SCF using different theoretical methods and comparing the results to the FE calculations. The theoeritical estimations are made using the Neuber, Inglis and Arola-Ramulu approaches, whereas COMSOL Multiphysics is used for the FE analyses. Comparing the theoeritical methods with the FE calculations, the Arola-Ramulu approach was better, with a maximum of error. The minimum deviations can be explained by the model containing parameters such as , and which are inherent to the roughness profile of the material.

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Section: Discussionmentioning

confidence: 99%

Characterising the notch root radii and analyses of stress concentration factors near the dominant valleys of rough surface profiles

Gebrehiwot,

Espinosa-Leal,

Remes

et al. 2023

RakMek

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“…Results show that the modified equations provide better correlations with the experimental data than the previous one. Subsequently, Hu et al studied the effect of notch geometry on the fatigue strength as well as the value of critical distance for TC4 titanium alloy. On the basis of vast test data, they concluded that K t related model proposed by Wang and Yang cannot perfectly account for the variation of the critical distance with the geometry sizes.…”

Section: Critical Distance Theory and Its Applications To Fatiguementioning

confidence: 99%

Recent advances on notch effects in metal fatigue: A review

Liao

Zhu

Correia

et al. 2020

Fatigue Fract Eng Mat Struct

173

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Notch features including holes, fillets, shoulders, and grooves commonly exist in engineering components. When subjected to external loads, these geometrical discontinuities generally act as stress raisers and thus present significant influences on the component strength and life, which are more remarkable under complex loading paths. Accordingly, numerous theories and approaches have been developed to address notch effects in metal fatigue as well as damage modelling and life predictions, which aim to provide theoretical support for structural optimal design and integrity evaluation. However, most of them are self‐styled or focus on specific objects, which limits their engineering applicability. This review recalls recent developments and achievements in notch fatigue modelling and analysis of metals. In particular, four commonly used methods for fatigue evaluation of metallic notched components/structures are summarized and elaborated, namely, nominal stress approaches, local stress‐strain approaches, and critical distance theories and weighting control parameters‐based approaches, which intend to provide a reference for further research on notch fatigue analysis and promote the integration and/or development among different approaches for practice.

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“…Furthermore, as each specimen is tested multiple times, the experimental time taken per specimen can be higher than staircase testing. Nevertheless, these effects have not been fully characterized, and the testing strategy remains in use across the academic literature 18–37 . For these reasons, step sizes are generally advised to be above 5% of the fatigue limit 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, these effects have not been fully characterized, and the testing strategy remains in use across the academic literature. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] For these reasons, step sizes are generally advised to be above 5% of the fatigue limit. 4 However, this requires prior knowledge of material properties and is dependent on the life being tested, as well as the continued debate over whether this is sufficient to avoid damage/coaxing.…”

mentioning

confidence: 99%

Bayesian optimized collection strategies for fatigue strength testing

Magazzeni

Rose

Gearhart

et al. 2022

Fatigue Fract Eng Mat Struct

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A statistical framework is presented enabling optimal sampling and analysis of constant life fatigue data. Protocols using Bayesian maximum entropy sampling are built based on conventional staircase and stress step methods, reducing the requirement of prior knowledge for data collection. The Bayesian Staircase method shows improved parameter estimation efficiency, and the Bayesian Stress Step method shows equal accuracy to the standard method at larger step size allowing experimentalists to lessen concerns of loading history. Statistical methods for determining model suitability are shown, highlighting the influence of protocol. Experimental validation is performed, showing the applicability of the methods in laboratory testing.

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Effect of notch geometry on the fatigue strength and critical distance of TC4 titanium alloy

Cited by 24 publications

References 21 publications

Characterising the notch root radii and analyses of stress concentration factors near the dominant valleys of rough surface profiles

Characterising the notch root radii and analyses of stress concentration factors near the dominant valleys of rough surface profiles

Recent advances on notch effects in metal fatigue: A review

Bayesian optimized collection strategies for fatigue strength testing

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