Prediction of fracture toughness dependence on constraint parameter A using the weakest link model

Comparison of the constraint parameters in elastic-plastic fracture mechanics

“…Change of the constraint conditions is achieved by varying crack length in the specimen. To avoid numerous experiments it is desirable to develop computational approaches for predicting the fracture toughness as a function of the constraint parameter A. Estimating change of the fracture toughness J C with variation of the constraint parameter A can be based on an assumption that fracture under different constraint conditions corresponds to constant fracture probability P f [19].…”

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

“…In the past few decades, on the basis of the crack‐tip stress field analysis, some constraint parameters, such as T ‐stress, 12 , Q , 13,14 A 2 , 15 A , 16–18 and T Z , 19,20 have been proposed and developed. Among these contributions, the parameters T ‐stress, Q , A , and A 2 are defined based on the plane strain–stress field at the crack tip, and they are primarily used to quantify the in‐plane constraint, which is related to crack depth or uncracked ligament length in a specimen or structure 21,22 .…”

“…This method is time consuming and costly. Thus, the methods based on the local fracture criterion (local approach) have been investigated and developed 17,27–29 . Such as in some studies, 17,27,28 the dependence of cleavage fracture toughness of materials on the constraint parameters ( A , Q , and T ‐stress) has been predicted according to the Beremin cleavage fracture model (the weakest link model) 30 .…”

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

“…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. Guo [13][14][15] proposed a parameter T z to quantify the out-of-plane constraint.…”

“…By determining the crack driving force parameters (such as stress intensity factor K or J ‐integral) and the constraint parameter, the fracture prediction or assessment of a specimen or component can be performed. The typical two‐parameter fracture mechanics like K‐T , 6 J‐A 2 , 7 J‐A , 8–10 and J‐Q 11,12 have been proposed and applied to the constraint‐dependent fracture assessments. The K‐T and J‐Q approaches have been included in some defect assessment procedures, such as in R6 29 and BS 7910 30 .…”