A node release approach to estimate J‐R curve for single‐edge‐notched tension specimen under reversed loading

Abstract

This paper proposes a node release approach to estimate the fracture resistance curve, often known as the J‐R curve, for monotonic and cyclic fracture tests. The node release approach simulates the crack extension by releasing the constraints imposed on the node at the crack tip and estimates the J‐R curve by coupling the domain integral value with the corresponding crack extension. This proposed node release approach estimates closely the J‐R curve for SE(B) and SE(T) specimens subjected to monotonic loading. For SE(T) specimen under cyclic loading, this study implements the node release analysis in two approaches: (1) an equivalent monotonic analysis corresponding to the envelope of the cyclic load‐CMOD response and (2) a direct cyclic simulation. Both approaches lead to close estimations of the experimentally measured J‐R curve. The numerical analysis also confirms the path independence of the domain integral values in the direct cyclic simulation.

Cyclic adaptive cohesive zone model to simulate ductile crack propagation in steel structures due to ultra‐low cycle fatigue

“…• Node release or element extinction, where either nodes are "untied" from the crack front 2 or elements are deleted from the mesh 3,4 once a rupture criterion is satisfied. • Softening constitutive models, 13 such as the popular Gurson 14 porous plasticity model, where damage is represented in the material constitutive response.…”

Measuring J‐R curve under dynamic loading conditions using digital image correlation

“…On the other hand, the J-integral resistance curve (J-R curve) represents the ductile fracture resistance from crack initiation to crack propagation and has versatile implementations in engineering components and specimens. 33,34 Under quasistatic conditions, ASTM E1820 4 documents standard procedures to determine the J-R curve. The standard method requires unloading and reloading to derive the elastic compliance of the specimen, which yields accurate prediction of the crack size and facilitates the J-integral calculation under an η approach.…”

Calibrating an adaptive cohesive zone model to simulate ductile crack propagation in structural steel under cyclic loading

“…Consequently, reliable simulation of ductile crack growth in such situations is important for structural performance assessment and design. 12 Methods for simulating crack propagation under monotonic loading by coupling conventional fracture mechanics rupture criteria with numerical techniques to simulate material separation are well-established 13,14 ; however, there is comparatively less development of continuum damage mechanics models to simulate crack propagation under cyclic loading. [15][16][17] In previous work, the authors developed and implemented a computational framework to simulate ductile crack propagation in steel components by integrating a continuum damage mechanics model, called the Stress-Weighted Ductile Fracture Model (SWDFM), with an Adaptive Cohesive Zone (ACZ) model to simulate crack growth.…”

“…Consequently, reliable simulation of ductile crack growth in such situations is important for structural performance assessment and design 12 . Methods for simulating crack propagation under monotonic loading by coupling conventional fracture mechanics rupture criteria with numerical techniques to simulate material separation are well‐established 13,14 ; however, there is comparatively less development of continuum damage mechanics models to simulate crack propagation under cyclic loading 15–17 …”