Tensile Fracture Analysis of Key-Hole Notches by Means of the Strain Energy Density

Torabi, A.R.; Campagnolo, Alberto; Berto, Filippo

doi:10.1007/s11223-016-9761-4

“…The most recent research on ductile failure of notched components has been performed by Torabi et al [20]. In [20], the experimentally recorded tensile LCCs of the V-notched Al 7075-T6 plates reported in [10] have been well predicted by means of the EMC in conjunction the well-known energy-based brittle fracture criterion, namely the averaged strain energy density (ASED) criterion [21][22][23][24][25][26][27]. It has been found in [20] that the EMC-ASED criterion could work well on mode I ductile failure of notched aluminum plates under the MSY failure regime.…”

mentioning

confidence: 95%

Large-Scale Yielding Failure Prediction of Notched Ductile Plates by Means of the Linear Elastic Notch Fracture Mechanics

Torabi

¹

,

Campagnolo

²

,

Berto

³

2017

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à Ëàáîðàòîðèÿ èññëåäîâàíèÿ ðàçðóøåíèÿ, Ôàêóëüòåò èííîâàöèîííûõ òåõíîëîãèé, Òåãåðàíñêèé óíèâåðñèòåò, Òåãåðàí, Èðàí á Ôàêóëüòåò îðãàíèçàöèè ïðîèçâîäñòâà, Ïàäóàíñêèé óíèâåðñèòåò, Ïàäóÿ, Èòàëèÿ â Ôàêóëüòåò ìåíåäaeìåíòà è èíaeèíèðèíãà, Ïàäóàíñêèé óíèâåðñèòåò, Âè÷åíöà, Èòàëèÿ ã Ìåõàíèêî-ìàøèíîñòðîèòåëüíûé ôàêóëüòåò, Íîðâåaeñêèé óíèâåðñèòåò åñòåñòâåííûõ è òåõíè-÷åñêèõ íàóê, Òðîíõåéì, Íîðâåãèÿ Ïðåäëîaeåí êðèòåðèé ðàçðóøåíèÿ, îñíîâàííûé íà ëèíåéíîé óïðóãîé ìåõàíèêå ðàçðóøåíèÿ, äëÿ ïðîãíîçèðîâàíèÿ èíèöèèðîâàíèÿ òðåùèíû ðàñòÿaeåíèÿ îò çàòóïëåííîãî V-îáðàçíîãî íàäðåçà ïðè áîëüøîé ïëàñòè÷íîñòè âáëèçè íàäðåçà. Îïèñàíû íåêîòîðûå ñîâðåìåííûå ýêñïåðèìåíòàëüíûå ðåçóëüòàòû ïî ðàçðóøåíèþ ïðè ðàñòÿaeåíèè ïëàñòè÷íûõ àëþìèíèåâûõ ïëàñòèí ñ V-îáðàçíûì íàäðåçîì. Ñ öåëüþ èçáåaeàíèÿ ñëîaeíîãî è òðóäîåìêîãî óïðóãîïëàñòè÷åñêîãî àíàëèçà äëÿ ïðîãíîçèðîâàíèÿ íåñóùåé ñïîñîáíîñòè àëþìèíèåâûõ ïëàñòèí ñ V-îáðàçíûì íàäðåçîì èñïîëüçóþòñÿ êîíöåïöèÿ ýêâèâàëåíòíîãî ìàòåðèàëà è êðèòåðèé óñðåäíåííîé ïëîòíîñòè ýíåðãèè äåôîðìàöèè, áàçèðóþùèéñÿ íà ëèíåéíîé óïðóãîé ìåõàíèêå ðàçðóøåíèÿ. Ïîêàçàíî õîðîøåå ñîîòâåòñòâèå ìåaeäó ýêñïåðèìåíòàëüíûìè äàííûìè è ðåçóëüòàòàìè ïðîãíîçèðîâàíèÿ íà îñíîâå êîíöåïöèè ýêâèâàëåíòíîãî ìàòåðèàëà è êðèòåðèÿ óñðåäíåííîé ïëîòíîñòè ýíåðãèè äåôîðìàöèè.Êëþ÷åâûå ñëîâà: íàäðåç, ïëàñòè÷íûé ìàòåðèàë, çàðîaeäåíèå òðåùèíû, ïîíÿòèå ýêâèâàëåíòíîãî ìàòåðèàëà, êðèòåðèé óñðåäíåííîé ïëîòíîñòè ýíåðãèè äåôîðìàöèè, ïîëíîìàñøòàáíîå òå÷åíèå.Introduction. In general, ductile metallic materials are divided into two main categories. The first and second categories involve those materials exhibiting negligible and considerable strain-hardening in the plastic zone, respectively. An accurate factor to realize the category is normally the difference between the yield and tensile strengths of the material. The fracture mechanics analyses for the two categories are really different. The

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“…Works [30,31] considered the representative volume for determining the average deformation energy controlling the state of pre-failure. If to consider the EP criterion in the element of the 00 δδ  interaction layer, the EP by virtue of Neuber's -Novozhilov's concept will be recorded as…”

Section: Finding Linear Dimensionmentioning

confidence: 99%

A Body Failure Model With a Notch Based on the Scalable Linear Parameter

2018

PNRPU MB

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Berto F., Glagolev V.V., Markin A.A. A Body Failure Model with a Notch Based on the Scalable Linear Parameter // Вестник Пермского национального исследовательского политехнического университета. Механика.Based on the concept of the interactive layer (IL), the paper considers the deformation of a body with a thin deep notch in a linearly elastic formulation. The stress state in the interactive layer is determined on the basis of the constitutive relations of the Prandtl bonds type. The proposed formulation of the task explicitly includes a linear parameter (LP). Based on the analytical solution of the task in the beam approximation, the dependence of the wedge force on the thickness (IL) is obtained. The use of the classical strength criteria in this dependence leads to a zero critical force at zero thickness IL, which contradicts the Griffith-Irvin criterion. We use it as a universal criterion for the destruction of the energy product (EP), as a product of a linear size and an increase in the specific free energy of the layer is shown. A relationship is established between the dimensions of the sample and the critical force, which ensures independence with a given degree of accuracy of the critical force from the thickness IL. By comparing the solution obtained and the classical solution for the notch in the form of a mathematical cut, the assumptions under which EP criterion and the Griffith's criterion (GC) coincide are determined. By using the Neuber-Novozhilov approach, the structural volume of the material with averaged characteristics of the stress-strain state (SSS) is identified. This volume is considered as a representative volume for determining the increment of еру average free energy that controls the state of pre-destruction. The product of the increment of the average free energy and LP determines the average EP. The expression for the average EP is determined on the basis of the obtained analytical solution. It is shown that the transition to the averaged value of the EP on a square Neuber cell does not lead to an increase in the margin of error in determining the critical force. It has been established that starting with a certain value of LP, which depends on the geometric characteristics of the damaged body, the convergence of the average EP in the pre-destruction zone to the GC takes place with a specified degree of accuracy. © PNRPU Keywords:quasi-brittle failure, linear size, pre-failure zone, energy product.

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“…So far, a wide range of analytical, numerical and experimental techniques have been developed to predict the failure of notched members subjected to various loading conditions. For instance, extensive studies have been conducted to obtain theoretical solutions for fracture prediction of various types of notches, including sharp V- [11][12][13][14], blunt V- [15,16], U- [17][18][19][20], key-hole [21][22][23][24] and VO-shaped [25,26] notches. As computers have become more powerful, recent research has been more focused on computational methods such as phase-field [27][28][29], extended finite-element [30][31][32][33] and mesh-free [34,35] simulations.…”

Section: Introductionmentioning

confidence: 99%

Data-driven based fracture prediction of notched components

Talebi,

Bahrami,

Daneshfar

et al. 2023

Phil. Trans. R. Soc. A.

1

0

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A data-driven approach is developed to predict the fracture load of a notched component. To do so, more than 1500 fracture tests (507 unique experimental data points) on mixed-mode I/II loading of notched brittle samples were collected from the literature. After pre-processing the raw data, six features of maximum tangential stress ( σ θ θ max ) , maximum tangential stress angle ( θ σ θ θ max ) , ultimate tensile strength ( σ u ) , fracture toughness ( K I c ) , notch opening angle ( 2 α ) and notch tip radius ( ρ ) were selected by using the neighbourhood component analysis (NCA) technique. To predict the fracture load of various types of notched samples, several machine learning (ML) models were trained using the methods of Gaussian process regression (GPR), decision tree ensemble and artificial neural network (ANN). Then, the Bayesian optimization algorithm was applied to find the optimum hyperparameters for each model. Lastly, the performance of the models in predicting fracture load was evaluated against 124 unseen data points. The results revealed the high potential of data-driven methods for assessing the fracture load of notched brittle components with acceptable precisions of 92%, 89% and 88% accuracy, respectively, for GPR, decision tree ensemble and ANN models. The superior performance of the GPR method can be attributed to its ability to capture complex nonlinear relationships in the data while providing reliable uncertainty estimates. Furthermore, thanks to its interpolation capabilities, GPR is able to seamlessly fill the gaps between data points, resulting in more comprehensive and precise predictions across the entire range of input data. Additionally, the presented models were capable of predicting the fracture load of VO-shaped notched samples with acceptable accuracy, though this type of notch was not used in the model training process. This article is part of the theme issue 'Physics-informed machine learning and its structural integrity applications (Part 2)'.

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Tensile Fracture Analysis of Key-Hole Notches by Means of the Strain Energy Density

Cited by 9 publications

References 53 publications

Large-Scale Yielding Failure Prediction of Notched Ductile Plates by Means of the Linear Elastic Notch Fracture Mechanics

Large-Scale Yielding Failure Prediction of Notched Ductile Plates by Means of the Linear Elastic Notch Fracture Mechanics

A Body Failure Model With a Notch Based on the Scalable Linear Parameter

Data-driven based fracture prediction of notched components

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