Two-parameter fracture prediction for cracked plates under bending

Unified creep constraint parameter solutions for surface cracks in plates under tensile and bending loads

“…The parameter A c for cracked plates was calculated using finite element method (FEM). The surface cracks in plates were simplified as regular semi-elliptic cracks, [52][53][54] as shown in Figure 1. The 2W, 2H, t, a, and 2c stand for the plate width, length, thickness, crack depth, and crack length, respectively.…”

“…49,50 In a recent work of authors, 51 the elastic-plastic constraint parameter A d was applied to predict the fracture toughness of single-edge-notched-bend (SEN[B]) test specimens. And based on the parameter A d , a load independent unified constraint parameter A d * 52,53 has been investigated and developed using the cracked plates. In a recent paper of authors, 54 the solutions of the parameter C* for surface cracked plates subjected to tensile and bending loads have been investigated and obtained.…”

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

“…For instance, for a crack in a plate, its CTOD value is δ J at a certain J ‐integral, and the CTOD value of a standard plane strain reference specimen (such as a SEN(B) specimen with B = 16 mm, W = 2 B , and a / W = 0.5 recommended by ASTM E1820 52 ) is δ Jref at the same J ‐integral. The ratio of δ J and δ Jref is the A d * value in Equation (1), which represents the constraint level of the plate crack 40,41 . If the A d * value of the plate crack is greater than one ( A d * > 1), it implies that its constraint level is lower than that of the standard plane strain reference specimen.…”

“…Equation (2) has been incorporated in ASTM E1820 52 for calculating CTOD from J ‐integral in fracture toughness test, and the expression of the parameter m as a function of crack depth a / W and material properties is given for the standard plane strain C(T) and SEN(B) specimens. For nonstandard specimens and the cracks in complex structures or components, the values of the constraint factors m need to be calculated by FE analysis 40,41,55–57 . In this work, Equation (2) is used in calculation of the constraint parameter A d *.…”

“…In the authors' previous study, 43 the correlations between fracture toughness of a DMWJ and a unified constraint parameter A p (it is defined by the crack‐tip plastic area) have been established. The newly developed unified constraint parameter A d * based on CTOD is load independent and convenient for engineering application 40,41 . A general quantitative correlation equation between the master curve reference temperature T 0 ( T 0 is a parameter for characterizing cleavage fracture toughness) and A d * has been established 50 .…”