Stress Intensity Factor of Inclined Internal Edge Crack in Cylindrical Pressure Vessel
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TECHNICAL ARTICLE—PEER-REVIEWED
Stress Intensity Factor of Inclined Internal Edge Crack in Cylindrical Pressure Vessel Arunkumar Subbaiah
. Ravikiran Bollineni
Submitted: 21 February 2020 Ó ASM International 2020
Abstract In this work, the stress intensity factor of inclined edge cracks introduced on the inner surface of a cylindrical pressure vessel is analyzed through numerical simulation. The fracture analysis was performed using a two-dimensional axisymmetric finite element model. The results reveal that, as the crack inclination increases beyond 30o, mode II loading becomes dominant. As the crack length increases, mode II loading acts in a profound manner in the component. In addition, the stress intensity factor of inclined crack was examined in the presence of multiple cracks. It was found that after a certain spacing between the inclined and neighboring crack, the ratio of mode I to mode II remains constant due to the non-interaction of stress fields around the crack. Keywords Fracture Pressure vessel Edge crack Stress intensity factor Numerical simulation List of Symbols a Crack length d Diameter of the pressure vessel l Distance between the cracks p Internal pressure t Thickness of the pressure vessel E Elastic modulus pf Failure pressure S22 Normal stress along Y-direction S12 Shear stress A. Subbaiah (&) R. Bollineni Department of Mechanical Engineering, Amrita Vishwa Vidyapeetham, Amritapuri, India e-mail: [email protected] R. Bollineni e-mail: [email protected]
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Angle of inclination of crack Normal stress Shear stress Hoop stress Longitudinal stress Equivalent von Mises stress Principal stresses Poisson’s ratio Yield strength Mode I stress intensity factor Mode II stress intensity factor
Introduction Pressure vessels are containers that transport and store fluids with a pressure gradient between outside and inside of the vessel [1]. During service, the vessel may fail due to various reasons. Failure is the inability of a component to deliver its intended function. The failure could be due to yielding, buckling, creep, fatigue, fracture, etc. Suppose, if the component contains preexisting defects, the cracks nucleate and propagate under the action of the applied loads (that is, internal pressure in the case of pressure vessels) and fail by fracture. Fracture is the fragmentation of a component into two or more pieces. The failure of the component due to yielding or bucking can be handled by conventional yield theories but not the problem of fracture. The conventional yield theories consider the component or the domain under investigation to be continuum. In this case, the application of fracture mechanics could give information about the integrity of the vessel. The subject of fracture mechanics deals with the behavior of bodies containing flaws or cracks, their interaction with the
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J Fail. Anal. and Preven.
applied stresses and the resistance of the material to fracture. This subject currently has widespread acceptance as a
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