Finite fracture mechanics and cohesive crack model: Weight functions vs. cohesive laws

Abstract

The present work represents the prosecution of a previous paper [Short cracks and V-notches: Finite Fracture Mechanics vs. Cohesive Crack Model (2016). P. Cornetti, A. Sapora, A. Carpinteri. Engineering Fracture Mechanics 168:2–12] aiming to corroborate the use of Finite Fracture Mechanics by showing that its failure load estimates are very close to the ones provided by the well-established Cohesive Crack Model. While the above paper focused only on the Dugdale cohesive law and the original Finite Fracture Mechanics approach, here we consider generic cohesive laws of power law type and propose an extension of Finite Fracture Mechanics based on stress weight functions. We argue that excellent agreement between the models is found provided proper correspondence rules between the shape of the cohesive laws and of the weight functions are given. As a test bench for this conjecture, we choose the Griffith crack geometry, where we are able to achieve the solutions in a semi-analytical way for both the models. Finally, we show that similar results can be obtained also by varying the domain of the weight function while keeping fixed its shape.