scholarly journals Estimating the critical stress intensity factor for an interfacial corner equivalent to an interfacial crack using the molecular statics and cohesive zone model

2021 ◽  
Author(s):  
Yuta ABUMI ◽  
Toru IKEDA ◽  
Masaaki KOGANEMARU
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cohesive Zone ◽  
Critical Stress ◽  
Cohesive Zone Model ◽  
Interfacial Crack ◽  
Critical Stress Intensity Factor ◽  
Zone Model ◽  
Molecular Statics

scholarly journals Critical value of the generalized stress intensity factor for a crack perpendicular to an interface

2015 ◽  
Vol 471 (2183) ◽  
pp. 20150571 ◽  
Author(s):  
George G. Adams
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Crack Tip ◽  
Critical Value ◽  
Zone Model ◽  
Cohesive Stress ◽  
Generalized Stress Intensity Factor

When a crack tip impinges upon a bi-material interface, the order of the stress singularity will be equal to, less than or greater than one-half. The generalized stress intensity factors have already been determined for some such configurations, including when a finite-length crack is perpendicular to the interface. However, for these non-square-root singular stresses, the determination of the conditions for crack growth are not well established. In this investigation, the critical value of the generalized stress intensity factor for tensile loading is related to the work of adhesion by using a cohesive zone model in an asymptotic analysis of the separation near the crack tip. It is found that the critical value of the generalized stress intensity factor depends upon the maximum stress of the cohesive zone model, as well as on the Dundurs parameters ( α and β ). As expected this dependence on the cohesive stress vanishes as the material contrast is reduced, in which case the order of the singularity approaches one-half.

scholarly journals Estimation of Cement Composites Fracture Parameters Using Deformation Criterion

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4206
Author(s):  
Marta Kosior-Kazberuk ◽  
Andrzej Kazberuk ◽  
Anna Bernatowicz
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Critical Stress ◽  
Load Capacity ◽  
Critical Stress Intensity Factor ◽  
Zone Model ◽  
Opening Displacement ◽  
Deformation Criterion ◽  
Maximal Load

A simple deformation criterion based on Dugdale’s cohesive zone model is presented. The criterion can be used for both the experimental determination of the critical stress intensity factor, KIc, and the critical tip opening displacement, CTODc. It can also be applied for the evaluation of the load capacity of structural elements. The criterion is presented in explicit and compact form, which allows straightforward calculations to be performed for the estimation of KIc and CTODc values from the experimental data obtained from samples with a U-shaped notch, rounded with an arbitrary radius. Thanks to the simple form of the approximate relationship between the maximal load level and the dimensionless notch tip opening displacement, the reverse procedure was obtained, i.e., the estimation of the value of the maximal force loading the structural element as a function of the known critical stress intensity factor.

Effect of Grain Size on the Fracture Toughness of Bimodal Nanocrystalline Materials

2014 ◽  
Vol 936 ◽  
pp. 400-408 ◽  
Author(s):  
Ying Guang Liu ◽  
Xiao Dong Mi ◽  
Song Feng Tian
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Grain Size ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cohesive Zone ◽  
Critical Stress ◽  
Crack Tip ◽  
Critical Stress Intensity Factor ◽  
Coarse Grain

To research the effect of grain size on the fracture toughness of bimodal nanocrystalline (BNC) materials which are composed of nanocrystalline (NC) matrix and coarse grains, we have developed a theoretical model to study the critical stress intensity factor (which characterizes toughness) of BNC materials by considering a typical case where crack lies at the interface of two neighboring NC grains and the crack tip intersect at the grain boundary of the coarse grain, the cohesive zone size is assumed to be equal to the grain sizedof the NC matrix. Blunting and propagating processes of the crack is controlled by a combined effect of dislocation and cohesive zone. Edge dislocations emit from the cohesive crack tip and make a shielding effect on the crack. It was found that the critical stress intensity factor increases with the increasing of grain sizedof the NC matrix as well as the coarse grain sizeD. Moreover, the fracture toughness is relatively more sensitive to the coarse grain size rather than that of NC matrix.

Investigation of Fracture Criterion for HTPB Propellant

2012 ◽  
Vol 591-593 ◽  
pp. 745-749
Author(s):  
Bo Han ◽  
Yu Tao Ju ◽  
Chang Sheng Zhou
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Cohesive Zone ◽  
Fracture Criterion ◽  
Cohesive Zone Model ◽  
Rate Effect ◽  
Zone Model ◽  
J Integral ◽  
Loading Rates ◽  
Htpb Propellant

The fracture toughness of HTPB propellant has a significant rate effect. In order to establish a fracture criterion considering rate effect for HTPB propellant, experiments were conducted at different loading rates. Two kinds of specimens were used to get the fracture properties. Stress intensity factor and J-integral were obtained by the single edge notched tension specimen test. A power law cohesive zone model was obtained by the experiment based inverse method. Through comparing we found that the stress intensity factor and J-integral cannot model the rate effect in fracture process. The cohesive zone model (CZM) has a constant critical separation distance at different loading rates and has a capability to model the rate effect during the crack initiation and propagation process. A finite element simulation in ABAQUS was given to demonstrate its capability to model the crack propagation.

scholarly journals Adhesion and pull-off force of an elastic indenter from an elastic half-space

2014 ◽  
Vol 470 (2169) ◽  
pp. 20140317 ◽  
Author(s):  
George G. Adams
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Half Space ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Elastic Half Space ◽  
Work Of Adhesion ◽  
Zone Model ◽  
Generalized Stress Intensity Factor ◽  
Elastic Punch

The adhesion between an elastic punch and an elastic half-space is investigated for plane and axisymmetric geometries. The pull-off force is determined for a range of material combinations. This configuration is characterized by a generalized stress intensity factor which has an order less than one-half. The critical value of this generalized stress intensity factor is related to the work of adhesion, under tensile loading, by using a cohesive zone model in an asymptotic analysis of the separation near the elastic punch corner. These results are used in conjunction with existing results in the literature for the frictionless contact between an elastic semi-infinite strip and half-space in both plane and axisymmetric configurations. It is found that the value of the pull-off force includes a dependence on the maximum stress of the cohesive zone model. As expected, this dependence vanishes as the punch becomes rigid in that case the order of the singularity approaches one-half. At the other limit, when the half-space becomes rigid, the stresses become bounded and uniform and the pull-off force depends linearly on the cohesive stress and is independent of the work of adhesion. Thus, the transition from fracture-dominated adhesion to strength-dominated adhesion is demonstrated.

Fracture of monolayer germanene: A molecular dynamics study

2018 ◽  
Vol 32 (22) ◽  
pp. 1850241 ◽  
Author(s):  
Minh-Quy Le
Keyword(s):  
Molecular Dynamics ◽  
Stress Intensity Factor ◽  
Tensile Strength ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Critical Stress ◽  
Axial Strain ◽  
Critical Stress Intensity Factor ◽  
Monolayer Graphene ◽  
Fracture Properties

Molecular dynamics simulations with Tersoff potential were performed to study the fracture properties of monolayer germanene at 300 K. The two-dimensional (2D) Young’s modulus, 2D tensile strength and axial strain at the tensile strength of pristine monolayer germanene are about 36.0 and 37.5 N/m; 5.1 and 4.6 N/m; 21.4 and 15.9%, in the zigzag and armchair directions, respectively. Griffith theory was applied to compute the critical stress intensity factor. Compared to monolayer graphene, the critical stress intensity factor of monolayer germanene is much smaller. Fracture pattern and effects of the initial crack length on the fracture properties are also studied. Results are useful for future design and applications of this 2D material.

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