Theoretical approach of characterizing the crack-tip constraint effects associated with material’s fracture toughness

Lv, Junnan; Yu, Lie; Du, Wei; Li, Qun

doi:10.1007/s00419-018-1392-8

Cited by 23 publications

(5 citation statements)

References 46 publications

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“…Recently different variations of Anderson -Dodds -Kirk unified measure of constraint have been considered and theoretical investigation on their validity has been performed (e.g. see [45,46]). For example, a CTOD based unified measure of constraint, .…”

Section: Unified Measure Of Constraintmentioning

confidence: 99%

Unifying the effects of in and out-of-plane constraint on the fracture of ductile materials

Tonge

Simpson

Reinhard

et al. 2020

Journal of the Mechanics and Physics of Solids

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Effects of plastic constraint on the fracture of materials have been studied extensively. Often in such studies, the plastic constraint is divided into in-plane and out-of-plane directions and each treated separately. Such a separation adds considerable complexity to the engineering structural integrity assessment analyses. Despite previous suggestions for unifying the effects of constraint in a single parameter, the current engineering assessments have not been updated due to lack of direct experimental validation of such parameters. In this study, we directly measured the effects of in-plane and out-of-plane constraints, for the first time, in the form of plastic zone around the crack using advanced experimental techniques. The measurement of constraints in four specimens with different levels of in and out of plane constraints, allowed us to show and relate the interdependency of in and out of plane constraints. The tests were carried out using synchrotron X-ray tomography with in-situ loading. Attenuation contrast between the constituents of the metal matrix composite material used allowed the tomograms to be analysed using digital volume correlation which calculated the full-field displacement within the samples. The displacement fields were used via a finite element framework to calculate the energy release rate in the form of the J-integral along the crack fronts. The measured plastic zone sizes, dependent on the combined level of in plane and out of plane constraints, were used successfully to rank the J-Integral at fracture of the samples. It was therefore proved the level of plastic constraint can be quantified by using the size of the plastic zone as without separating it into two components thus simplifying the treatment of constraint in structural analyses significantly.

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Section: Unified Measure Of Constraintmentioning

confidence: 99%

Unifying the effects of in and out-of-plane constraint on the fracture of ductile materials

Tonge

Simpson

Reinhard

et al. 2020

Journal of the Mechanics and Physics of Solids

View full text Add to dashboard Cite

show abstract

“…It has been shown that the two parameters A p and A d can characterize both in‐plane and out‐of‐plane constraints for specimens and cracked components under both brittle and ductile fracture conditions 24–26 . Recent theoretical analyses and experimental investigations in the literature 5,27,28 further verify the ability of the crack‐tip plastic area to measure both in‐plane and out‐of‐plane constraints.…”

Section: Introductionmentioning

confidence: 94%

“…Constraints can be divided into in-plane and out-of-plane constraints, 3 and the former is associated with crack depth, specimen geometry, and loading type, whereas the latter is mainly related to the specimen thickness. 4,5 Various constraint parameters have been proposed by researchers to quantify the constraint effects, and their capabilities for characterizing both constraints are different. The linear-elastic T-stress (T 11 ), 6 A 2 , 7 A, [8][9][10] and Q 11,12 can characterize the in-plane constraint.…”

Section: Introductionmentioning

confidence: 99%

Validation and application of a two‐parameter J‐A_d approach for fracture behaviour prediction

Wang

et al. 2020

Fatigue Fract Eng Mat Struct

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In this work, the two-parameter J-A d approach was applied to predict thefracture toughness of test single-edge-notched-bend (SEN(B)) specimens with different in-plane and out-of-plane constraints for two materials with different mechanical properties. The results show that for most SEN(B) specimens, the predicted fracture toughness agrees with the experimental data; thus, the capability and applicability of the two-parameter J-A d approach are validated. The approach correctly predicts that the fracture toughness decreases with increasing in-plane and out-of-plane constraints. Compared with the prediction results of the three-parameter J-Q-T z approach in the literature, the J-A d approach has better prediction accuracy and wider application ranges. The calculation procedure of the J-A d approach is also simple and convenient for engineering application.

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“…[19][20][21][22] To capture both in-plane and out-of-plane constraints in structures containing defects, over the last decade, the unified constraint parameters have been investigated and developed. 1,2,[32][33][34][35][36] These parameters are usually defined based on the area or size of the crack-tip plastic zone. Because the essence of constraint is an obstruction of a structure geometry against the plastic deformation at the crack tip, 37 overall constraint level (it consists of both constraints) in a structure or specimen may be directly measured by the plastic deformation amount around the crack tip.…”

Section: Introductionmentioning

confidence: 99%

“…In applying these correlation equations in fracture assessment, the out‐of‐plane constraint effect in actual three‐dimensional (3D) defective structures may not be fully captured 19–22 . To capture both in‐plane and out‐of‐plane constraints in structures containing defects, over the last decade, the unified constraint parameters have been investigated and developed 1,2,32–36 . These parameters are usually defined based on the area or size of the crack‐tip plastic zone.…”

Section: Introductionmentioning

confidence: 99%

Correlation between fracture toughness and constraint of bi‐material interfaces with different mechanical mismatches

Xiao

Wang

Xuan

et al. 2022

Fatigue Fract Eng Mat Struct

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In this work, the correlation between ductile fracture toughness and a new unified constraint parameter A d * for bi-material interfaces with different mechanical mismatches (strength and hardening mismatches) has been investigated based on finite element analysis and experimental data validation. The results show that with increasing crack depth (geometric constraint) and mechanical mismatch level (increasing undermatch or overmatch level), the J-R curves and fracture toughness J C of bi-material interfaces decrease. The constraint parameter A d * values of bi-material interface cracks are basically independent of the strength and hardening mismatches. A general correlation equation between fracture toughness J C and constraint parameter A d * has been obtained, which may be applied to prediction of fracture toughness of any specimens or components with different geometric constraints and material properties mismatches (including homogeneous materials). The prediction capability of the correlation equation has been validated by experimental fracture toughness data of cracks with different strength and hardening mismatches in dissimilar metal welded joints.

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Theoretical approach of characterizing the crack-tip constraint effects associated with material’s fracture toughness

Cited by 23 publications

References 46 publications

Unifying the effects of in and out-of-plane constraint on the fracture of ductile materials

Unifying the effects of in and out-of-plane constraint on the fracture of ductile materials

Validation and application of a two‐parameter J‐A_d approach for fracture behaviour prediction

Correlation between fracture toughness and constraint of bi‐material interfaces with different mechanical mismatches

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Theoretical approach of characterizing the crack-tip constraint effects associated with material’s fracture toughness

Cited by 23 publications

References 46 publications

Unifying the effects of in and out-of-plane constraint on the fracture of ductile materials

Unifying the effects of in and out-of-plane constraint on the fracture of ductile materials

Validation and application of a two‐parameter J‐Ad approach for fracture behaviour prediction

Correlation between fracture toughness and constraint of bi‐material interfaces with different mechanical mismatches

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Validation and application of a two‐parameter J‐A_d approach for fracture behaviour prediction