Effect of Geometrical Crack Parameters on SIF in a SphericalPressurized Vessel

Pressure vessels are of great importance in various industries nowadays. These vessels usually suffer from defects such as cracks due to manufacturing process. Therefore analyzing their fracture mechanics properties such as stress intensity factor (SIF) is necessary for a safe design and maintenance. In this study a spherical pressure vessel with internal and external semi-elliptical cracks on it’s circumference is considered. Effect of various properties such as aspect ratio, crack angle (with respect to horizontal) and etc. are analyzed. Results show that internal cracks have lower SIF than external ones and for both internal and external cracks, at a constant crack depth increasing aspect ratio (a/c) transfers point of maximum SIF from deepest point to corner points. A finite element analysis using ABAQUS along withZENCRACK is performed to evaluate J contour integral and indeed SIF for each set of vessel and crack configuration.SIFs for a simpler model are calculated with the same approach and compared to the results from literatures. A good agreement is seen between the results and indeed the approach is verified.

Keywords:

Pressure Vessel , Stress Intensity Factor , Crack