scholarly journals Mechanics of the crack path formation

1991 ◽  
Vol 47 (4) ◽  
pp. 291-305 ◽  
Author(s):  
Asher A. Rubinstein
Keyword(s):  
Crack Path

Comparison of DBEM and FEM Crack Path Predictions with Experimental Findings for a SEN-Specimen under Anti-Plane Shear Loading

2007 ◽  
Vol 348-349 ◽  
pp. 129-132 ◽  
Author(s):  
Roberto G. Citarella ◽  
Friedrich G. Buchholz
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Front ◽  
Crack Path ◽  
Shear Loading ◽  
Crack Growth Behaviour ◽  
3D Crack Growth ◽  
Corner Points ◽  
Experimental Findings

In this paper detailed results of computational 3D fatigue crack growth simulations will be presented. The simulations for the crack path assessment are based on the DBEM code BEASY, and the FEM code ADAPCRACK 3D. The specimen under investigation is a SEN-specimen subject to pure anti-plane or out-of-plane four-point shear loading. The computational 3D fracture analyses deliver variable mixed mode II and III conditions along the crack front. Special interest is taken in this mode coupling effect to be found in stress intensity factor (SIF) results along the crack front. Further interest is taken in a 3D effect which is effective in particular at and adjacent to the two crack front corner points, that is where the crack front intersects the two free side surfaces of the specimen. Exactly at these crack front corner points fatigue crack growth initiates in the experimental laboratory test specimens, and develops into two separate anti-symmetric cracks with complex shapes, somehow similar to bird wings. The computational DBEM results are found to be in good agreement with these experimental findings and with FEM results previously obtained. Consequently, also for this new case, with complex 3D crack growth behaviour of two cracks, the functionality of the proposed DBEM and FEM approaches can be stated.

scholarly journals Embedded flaws for crack path control in composite laminates

2014 ◽  
Vol 66 ◽  
pp. 218-226 ◽  
Author(s):  
Adrian C. Orifici ◽  
Phisit Wongwichit ◽  
Nuth Wiwatanawongsa
Keyword(s):  
Composite Laminates ◽  
Crack Path ◽  
Path Control

Crack path selection in piezoelectric bimaterials

1999 ◽  
Vol 47 (1-4) ◽  
pp. 519-524 ◽  
Author(s):  
Qing-Hua Qin ◽  
Yiu-Wing Mai
Keyword(s):  
Crack Path ◽  
Path Selection ◽  
Crack Path Selection

Crack-Path Effect on Material Toughness

1990 ◽  
Vol 57 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Asher A. Rubinstein
Keyword(s):  
Crack Path ◽  
Numerical Procedure ◽  
Crack Tip ◽  
Elastic Solid ◽  
Singular Integral Equations ◽  
Length Change ◽  
Curvilinear Crack ◽  
Linear Elastic ◽  
System Of Cracks ◽  
Remote Stress

The material-toughening mechanism based on the crack-path deflection is studied. This investigation is based on a model which consists of a macrocrack (semi-infinite crack), with a curvilinear segment at the crack tip, situated in a brittle solid. The effect of material toughening is evaluated by comparison of the remote stress field parameters, such as the stress intensity factors (controlled by a loading on a macroscale), to effective values of these parameters acting in the vicinity of a crack tip (microscale). The effects of the curvilinear crack path are separated into three groups: crack-tip direction, crack-tip geometry pattern-shielding, and crack-path length change. These effects are analyzed by investigation of selected curvilinear crack patterns such as a macrocrack with simple crack-tip kink in the form of a circular arc and a macrocrack with a segment at the crack tip in the form of a sinusoidal wave. In conjunction with this investigation, a numerical procedure has been developed for the analysis of curvilinear cracks (or a system of cracks) in a two-dimensional linear elastic solid. The formulation is based on the solution of a system of singular integral equations. This numerical scheme was applied to the cases of finite and semi-infinite cracks.

Characterization of Crack Tip Damage Zone Formation on Alloy 625 During Fatigue Crack Growth at 750°C by Transmission EBSD Method

2017 ◽  
Author(s):  
Yuji Ozawa ◽  
Tatsuya Ishikawa ◽  
Yoichi Takeda
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Power Plants ◽  
Crack Path ◽  
Damage Zone ◽  
Crack Tip ◽  
Loading Frequency ◽  
Zone Formation ◽  
Alloy 625

In order to clarify the mechanism of fatigue crack growth in alloy 625, which is a candidate material for use in advanced ultra supercritical power plants, the crack tip damage zone formation after a crack growth test conducted in high temperature steam was investigated. It was observed that the oxide thickness at the crack tip tended to increase with decreasing cyclic loading frequency. The crack path was a mix of transgranular and intergranular fractures. According to the grain reference orientation deviation (GROD) maps, it was revealed that the density of geometrically necessary dislocations (GNDs) in the matrix along the crack path and ahead of crack tip increased with an increase in the fatigue crack growth rate (FCGR) due to environmental effects. It was observed that (1) mobile dislocations at the crack surface were blocked due to the thick oxide layer, resulting in an increase in the density of GNDs, and (2) an increase in the density of GNDs might induce stress concentration at the crack tip, deformation twinning, and the acceleration of FCGRs.

Probabilistic Model of Surface Crack on the Lumbar Vertebra

2013 ◽  
Vol 471 ◽  
pp. 299-305
Author(s):  
A. Zulkifli ◽  
Ahmad K. Ariffin ◽  
M.R.M. Akramin
Keyword(s):  
Finite Element Method ◽  
Surface Crack ◽  
Maximum Stress ◽  
Crack Path ◽  
Lumbar Vertebra ◽  
Crack Size ◽  
Probability Of Failure ◽  
Biological Models ◽  
Probabilistic Study ◽  
Model Components

The objectives of this study are to determine the stress intensity factor (SIF) for different surface crack size of the lumbar vertebra and the probability of failure associated with finite element method. In this work, all the model components were meshed using the tetrahedral solid element. In order to simplify the model, all the spinal components were modeled as an isotropic and elastic material. Monte Carlo Simulation (MCS) technique was performed to conduct the probabilistic analysis using a probabilistic module in ANSYS with attempt for 100 trials. The results are observed that the maximum SIF were found in the end of crack path with 0.53 MPa.m1/2 and the corresponding probability of failure for the model is 1.22%. Sensitivity analysis had been revealed that the crack size was sensitive to the maximum stress and maximum SIF output parameters with correlation 0.989 and 0.811 respectively. The current probabilistic study is useful as a tool to understand the inherent uncertainties and variations in biological models.

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