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

Abstract

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.

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

“…The CPE4R elements with reduced integration are commonly used in FEM fracture mechanics analysis for 2D cracked specimens. 38,[47][48][49] mesh configuration with a focused ring of elements is used at the blunt crack tip with a small initial root radius (r 0 = 2.5 μm), [38][39][40] as shown in Figure 3B. According to the mesh sensitivity analyses, the crack-tip minimum element size of 0.39 μm is applied.…”

“…Figure 3 shows the FE model of a typical SENB specimen ( a / W = 0.5). To accurately calculate the crack‐tip fracture parameters ( J ‐integral and CTOD) for stationary cracks, a mesh configuration with a focused ring of elements is used at the blunt crack tip with a small initial root radius ( r 0 = 2.5 μm), 38–40 as shown in Figure 3B. According to the mesh sensitivity analyses, the crack‐tip minimum element size of 0.39 μm is applied.…”

“…38 The correlation between fracture toughness and parameter A d has been established for low-alloy steels, and the J-A d two-parameter method also has been developed for prediction of defective structures' fracture behavior. 3,4,39 Recently, a new load-independent unified constraint parameter A d * has been further developed based on the parameter A d . 40 A correlation curve between ductile fracture toughness and A d * was established for a steel and applied in fracture prediction of cracked plates.…”

“…Because the crack‐tip opening displacement (CTOD) can simply measure the crack‐tip plastic deformation amount, a unified constraint parameter A d has been proposed on the basis of CTOD 38 . The correlation between fracture toughness and parameter A d has been established for low‐alloy steels, and the J‐A d two‐parameter method also has been developed for prediction of defective structures' fracture behavior 3,4,39 . Recently, a new load‐independent unified constraint parameter A d * has been further developed based on the parameter A d 40 .…”

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

“…And based on the T-stress solutions, the Q factor solutions for cracked plates under tensile and bending loads have been obtained. 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.…”