Application of the virtual crack closure technique to calculate stress intensity factors for through cracks with an elliptical crack front

1998 ◽  
Vol 59 (3) ◽  
pp. 327-342 ◽  
Author(s):  
S.A. Fawaz
Keyword(s):  
Stress Intensity ◽  
Crack Closure ◽  
Stress Intensity Factors ◽  
Crack Front ◽  
Elliptical Crack ◽  
Virtual Crack Closure Technique ◽  
Intensity Factors ◽  
Closure Technique

Quarter-Point Elements Are Unnecessary for the VCCT

2020 ◽  
Vol 87 (8) ◽  
Author(s):  
Elad Farkash ◽  
Leslie Banks-Sills
Keyword(s):  
Stress Intensity ◽  
Energy Release ◽  
Crack Closure ◽  
Stress Intensity Factors ◽  
Virtual Crack Closure Technique ◽  
Intensity Factors ◽  
Release Rates ◽  
Closure Technique ◽  
Established Method ◽  
Energy Release Rates

Abstract The virtual crack closure technique (VCCT) is a well-established method for determining energy release rates and stress intensity factors in homogeneous, isotropic materials. It has been implemented with four-noded, eight-noded, quarter-point, and other higher order elements. It is most convenient and accurate when used with eight-noded, isoparametric elements. VCCT produces less accurate results when used with quarter-point elements. Yet, this method continues to be employed with quarter-point elements. It is strongly recommended to use VCCT with regular eight-noded elements. Three examples will be presented to illustrate the inaccuracy when using quarter-point elements with VCCT.

Stress Intensity Factors for Surface Semi-Elliptical Crack in Cylindrical Specimen under Combined Torsion and Axial Compression

2010 ◽  
Vol 452-453 ◽  
pp. 673-676
Author(s):  
Jana Horníková ◽  
Pavel Šandera ◽  
Jaroslav Pokluda
Keyword(s):  
Stress Intensity ◽  
Axial Compression ◽  
Stress Intensity Factors ◽  
Crack Front ◽  
Fatigue Cracks ◽  
Elliptical Crack ◽  
Crack Plane ◽  
Shear Cracks ◽  
Intensity Factors ◽  
Principal Axes

Some authors proposed to combine a torsional loading of cylindrical specimens with surface semi-elliptical cracks (the principal axes along the axial direction) with superimposed static axial compression in order to eliminate kinking or branching of shear cracks from the shear plane. To authors’ knowledge, however, no precise numerical analysis of such a loading configuration is currently available. The aim of this article is to calculate stress intensity factors KI, KII and KIII along the semi-elliptical crack front using the ANSYS code. The problem is solved for a semi-circular crack front and various crack inclination angles. The results reveal that the compressive loading cannot eliminate the branching process. The inclination of the crack plane induces a rather high opening mode which means that the microscopically tortuous fatigue cracks observed in experiments grew under mixed-mode I+II+III.

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