Size effect in fatigue based on the extreme value distribution of defects

Makkonen, Lasse; Rabb, R.; Tikanmäki, Maria

doi:10.1016/j.msea.2013.11.045

Cited by 23 publications

(10 citation statements)

References 11 publications

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“…previous work [37,39], to use an extension of the Murakami approach [20] proposed by Makkonen et al [40]. As per this approach, the cumulative distribution function of the critical pore size at the crack initiation site associated with the loaded volume V is given by:…”

Section: Pore Size Distribution Used For Fatigue Strength Predictionmentioning

confidence: 99%

Interpretation of the fatigue anisotropy of additively manufactured TA6V alloys via a fracture mechanics approach

Pessard

Morel

et al. 2019

Engineering Fracture Mechanics

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This work is focused on the influence of porosity when dealing with the fatigue behaviour of TA6V alloys fabricated by the selective laser melting (SLM) process. The presence of porosity is one of the major issues facing additive manufacturing (AM) of metallic components subjected to fatigue loading. In order to study the effect of porosity on the fatigue behaviour, a vast experimental campaign has been undertaken. Seven specimen batches, fabricated by the SLM process with different building directions (horizontal, vertical and diagonal) were tested and a large amount of data was obtained. The link between the applied stress, the fatigue life and the pore size is highlighted by using generalized Kitagawa-Takahashi maps. It is shown that the effect of porosity on the fatigue strength is much more pronounced compared to the effect of the mi-crostructure. In the modelling section, two approaches based on fracture mechanics are considered. The first one is based on the Paris law which is used to model long fatigue crack growth. The second approach was proposed by Caton et al. (2001) for modelling small fatigue crack growth. Finally, a simulation of the generalized Kitagawa-Takahashi is presented and good agreement with the experimental data is shown.

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Section: Pore Size Distribution Used For Fatigue Strength Predictionmentioning

confidence: 99%

Interpretation of the fatigue anisotropy of additively manufactured TA6V alloys via a fracture mechanics approach

Pessard

Morel

et al. 2019

Engineering Fracture Mechanics

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“…The different measurements are then used to build and identify a Large Extreme Value Distribution (LEVD) associated to the defect size [16,17]. This statistical law, which is associated to the inspected section S 0 , can then be manipulated to predict the LEVD associated to the volume V of the loaded part by accounting for volume effects [18]. More recently, a similar concept of extreme value statistics was applied on CT scan observations to assess the probability related to the size of the largest defect contained in the volume V of AlSi10Mg parts produced by SLM [19].…”

Section: Introductionmentioning

confidence: 99%

Effect of hot isostatic pressing on the critical defect size distribution in AlSi7Mg0.6 alloy obtained by selective laser melting

Bonneric

Brugger

Saintier

2020

International Journal of Fatigue

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This study focuses on the influence of defect density on the sizes of the critical defects responsible for fatigue failure in AlSi7Mg0.6 alloy produced by Selective Laser Melting. Samples having similar microstructures and different defect densities were obtained combining Hot Isostatic Pressing and T6 treatments. Defect populations were analyzed using X-ray tomography, and fatigue tests were performed to determine the critical defect distributions. A method allowing for the prediction of these distributions from the CT scan data was then proposed, and discussed with regard to the actual distributions obtained from the fatigue tests.

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“…In order to assess the decrease in fatigue strength with elevated probabilities of critical defects, the EVIR methodology of Murakami [68] is invoked, as utilized in various preliminary studies [83,84,85]. Hereby, a reduced variate yj is calculated and plotted in a Gumbel probability paper—see Figure 12.…”

Section: Resultsmentioning

confidence: 99%

On the Statistical Size Effect of Cast Aluminium

et al. 2019

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Manufacturing process based imperfections can reduce the theoretical fatigue strength since they can be considered as pre-existent microcracks. The statistical distribution of fatigue fracture initiating defect sizes also varies with the highly-stressed volume, since the probability of a larger highly-stressed volume to inherit a potentially critical defect is elevated. This fact is widely known by the scientific community as the statistical size effect. The assessment of this effect within this paper is based on the statistical distribution of defect sizes in a reference volume V 0 compared to an arbitrary enlarged volume V α . By implementation of the crack resistance curve in the Kitagawa–Takahashi diagram, a fatigue assessment model, based on the volume-dependent probability of occurrence of inhomogeneities, is set up, leading to a multidimensional fatigue assessment map. It is shown that state-of-the-art methodologies for the evaluation of the statistical size effect can lead to noticeable over-sizing in fatigue design of approximately 10 % . On the other hand, the presented approach, which links the statistically based distribution of defect sizes in an arbitrary highly-stressed volume to a crack-resistant dependent Kitagawa–Takahashi diagram leads to a more accurate fatigue design with a maximal conservative deviation of 5 % to the experimental validation data. Therefore, the introduced fatigue assessment map improves fatigue design considering the statistical size effect of lightweight aluminium cast alloys.

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Size effect in fatigue based on the extreme value distribution of defects

Cited by 23 publications

References 11 publications

Interpretation of the fatigue anisotropy of additively manufactured TA6V alloys via a fracture mechanics approach

Interpretation of the fatigue anisotropy of additively manufactured TA6V alloys via a fracture mechanics approach

Effect of hot isostatic pressing on the critical defect size distribution in AlSi7Mg0.6 alloy obtained by selective laser melting

On the Statistical Size Effect of Cast Aluminium

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