Effect of Crack Location and Orientation on Crack Growth in Boiler Tube: Theoretical and Computational Investigation

Introduction/Importance of Study:Safety is the paramount concern in the operations and inspections of pressure vessels, such as water tube boilers. Defects in the boiler tubes can lead to the development of cracks.Novelty Statement:The investigation focuses on the effect of crack location and orientation on crack growth under cyclic loading which has been analyzed computationally using Separate Morphing and Re-meshing Technology (SMART) in ANSYS. The effect of location on crack growth is primarily focused which is theoretically investigated as well using Simpson’s Integration of Paris’s Law. Materials and Method:The tube in focus is a component of a D-type water-tube industrial boiler, crafted from low-carbon steel (SA 178 A). For the effect of location,semi-elliptical cracks on inner and outer tube surfaceshavebeenstudied both theoretically and computationally.Results and Discussion:Theoretical investigation revealed that cracks on the inner tube surface exhibit a 30.28% higher accumulative growth rate compared to the outer surface, attributed to hoop stress distribution. For investigating the effect of orientation elliptical embedded cracks at certain orientations have beenexamined computationally and the critical plane orientation for crack growth is identified as perpendicular to the hoop stress.Concluding Remarks:In conclusion, the study underscores that cracks grow faster when located at the inner surface and oriented perpendicular to the hoop stress.