Comparison between cohesive zone and coupled criterion modeling of crack initiation in rhombus hole specimens under quasi-static compression

Abstract

Numerical predictions of initiation loading and crack length in a rhombus hole specimen made of a brittle material under quasi-static compression using either cohesive zone model or coupled criterion based on finite fracture mechanics are compared. Both methods lead to the conclusion that crack initiation results in a crack jump over a finite length at a given loading level, which depends on the material parameters and on the specimen geometry. The initiation load level and crack extent depend on the cohesive zone traction-opening displacement profile which represents the underlying failure mechanism. The ranges of initiation force and crack lengths obtained with various traction-opening profiles respectively comprise the initiation force and lower bound for crack arrest derived from the coupled criterion. For the configuration under investigation, similar initiation forces and crack arrest lengths as those predicted using the coupled criterion are obtained using a bilinear cohesive zone model.

Brittle Failure of Nanoscale Notched Silicon Cantilevers: A Finite Fracture Mechanics Approach

“…Over the past decades, the approach has been applied or extended successfully to a large variety of problems, both in static and fatigue, by considering different materials, features and loading conditions, e.g., to rounded V-notches made of ceramic, metallic and plastic materials [36,37], crack at interfaces and at bi-material junctions [38,39], 3-D failure onset from sharp V-notch edge [40], failure initiation at the atomic scale by means of molecular simulations [41], multiaxial loading conditions and notch sensitivity [42,43], moderate and large scale yielding regimes [44]. Furthermore, FFM predictions have been recently proved to be very close to those by the powerful cohesive zone model (CZM) in different research frameworks [45][46][47][48], so one can use FFM for preliminary sizing in structural design, letting the CZM for subsequent study refinements. By considering the advantages of the FFM approach and the similitude with other methods successfully applied to small scale specimens, it is worth investigating the validity of the FFM at the nanoscale.…”

Experimental and Numerical Investigation on C/SiC Composite Z-Pinned/Bonded Hybrid Single-Lap Joints

“…In addition, studies [ 36 , 37 , 38 ] have shown that the mesh size of cohesive elements can affect the accuracy of the results. The material characteristic length is predicted as [ 37 , 38 ]: where is the Young modulus of the material, is the critical energy release rate, and is the maximum interfacial strength. Hence, can be obtained, and it is 37.66 mm.…”

Numerical implementation of the coupled criterion: Matched asymptotic and full finite element approaches

“…Crack length lower bound Crack length upper bound rate G when l → 0. Note that G can be expressed as a function of G inc [15,20,21,23], which can be useful to study crack propagation after initiation. However, this point will not be treated in this work which is exclusively dedicated to the prediction of crack initiation.…”

“…However, the asymptotic approach is only valid if the crack length remains small compared to the characteristic structure dimensions [19]. Moreover, the MA approach allows computing the initiation configuration but is unable to deal with unstable crack propagation that possibly occurs after initiation, which can be accounted for using the FFE approach [15,20,21,22,23,24]. Some authors compared the MA and FFE implementation of the CC.…”