Unified constraint parameter based on crack-tip opening displacement

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

“…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][25][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.…”

“…The two-parameter approach can be used for fracture analysis of any specimens and structures. 8,20,24,26,39,40 In this work, to validate the J-A d two-parameter approach, extensive experimental fracture toughness data of SEN(B) specimens having various sizes (different inplane and out-of-plane constraints) measured by Neimitz and Galkiewicz 35 were used. The experimental materials are 40H steel with two different heat treatments, namely, material A and material B.…”

“…The CTOD-based unified constraint parameter A d was defined by the following equation. 24 A where δ is the CTOD of a defected specimen or component and δ ref is the reference CTOD at fracture of a standard high-constraint specimen. The constraint can be regarded as the resistance of a structure against crack-tip plastic deformation; thus, it may be measured by the crack-tip plastic deformation amount which is related to CTOD.…”

“…The constraint can be regarded as the resistance of a structure against crack-tip plastic deformation; thus, it may be measured by the crack-tip plastic deformation amount which is related to CTOD. 24 Therefore, the parameter A d may reflect the physics of the crack-tip constraint. It has been shown that A d can characterize both in-plane and out-of-plane constraint effects.…”

The Characterization of the Stress Fields Near a Crack Tip for a Compact Specimen for Elastic-Plastic Materials Dominated by the Plane Strain State

“…Therefore, a unified constraint parameter which can characterize both constraints is required for a more accurate fracture assessment. In recent years, some unified constraint parameters have been proposed and developed [47][48][49][50][51].…”