Three-dimensional mixed-mode stress intensity factors for deflected external surface cracks in thin and midsize-thick-walled spherical pressure vessels

2021 ◽  
pp. 104596
Author(s):  
Ali O. Ayhan ◽  
Emre Kurt
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
External Surface ◽  
Three Dimensional ◽  
Pressure Vessels ◽  
Surface Cracks ◽  
Intensity Factors ◽  
Mode Stress ◽  
Spherical Pressure

A General Numerical Procedure for Extracting Mixed-Mode Stress Intensity Factors Along the Fronts of Three-Dimensional Nonplanar Cracks

2002 ◽  
Author(s):  
M. Gosz ◽  
R. Cammino
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Intensity Factors ◽  
Hydrostatic Tension ◽  
Energy Integrals ◽  
Shaped Crack ◽  
Mode Stress

A numerical procedure is described for extracting mixed-mode stress intensity factors along the fronts of three-dimensional, nonplanar cracks embedded in solids. The mixed-mode stress intensity factors at points along the crack front are obtained by evaluating interaction energy integrals for three-dimensional, non-planar cracks. To assess the validity of the numerical procedure, two numerical examples are considered. First, we consider the problem of a non-planar, lens-shaped crack in an infinite solid subjected to hydrostatic tension. The numerical results are shown to be in excellent agreement with available analytical results. We then consider the case of a non-planar, warped elliptical crack surface, where to our knowledge no analytical solution exists, and the results are discussed.

Stress Intensity Factors for High Aspect Ratio Semi-Elliptical External Surface Cracks in Cylindrical Vessels

2014 ◽  
Vol 986-987 ◽  
pp. 882-886
Author(s):  
Hong Yu Qi ◽  
Peng Chao Guo
Keyword(s):  
Stress Intensity ◽  
Aspect Ratio ◽  
Stress Intensity Factors ◽  
High Aspect Ratio ◽  
External Surface ◽  
Superposition Principle ◽  
Three Dimensional ◽  
Surface Cracks ◽  
Intensity Factors ◽  
Aspect Ratios

External surface cracks can occur in cylindrical vessels due to damage and propagate in the manufacturing process and during service life. Most of research focuses on stress intensity factors for surface cracks with low aspect ratios, i.e., a/c ≤1.0. Situation may well arise where the aspect ratio of cracks is larger than one. An external longitudinal surface crack is assumed to be subjected to different types of hoop stress distributions acting perpendicular to the crack faces. The stress intensity factors (SIFs) along the crack front were determined through the three-dimensional finite element method. Then these results are used to compute approximate values of SIFs in the case of complex loadings by employing both the superposition principle and the power series expansions of the actual hoop stresses. It is found that the maximum stress intensity factor for external surface cracks with high aspect ratio occurs at different point to that with low aspect ratio.

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