Fracture of underwater notched structures

Abstract

Underwater structures are subjected to hydrostatic pressure during their service life. Sharp Vnotched components can be seen as a part of many underwater structures. For example, welded components, machined parts, gears, screws and bolts are among the well-known elements that contain sharp V-notches. The notch tip is a likely zone for initiation of cracks due to high stress/ strain concentration. The reliability analysis of the V-notched components requires a good understanding of stress/ strain distribution near the notch tip. The fracture initiation of the Vnotched components can be controlled by the tangential strain field near the notch tip. The tangential strain distribution and fracture initiation conditions are studied in this paper for notched components subjected to hydrostatic pressure. The effect of each tangential strain term on fracture initiation angle as well as tangential strain distribution around the notch tip is investigated using finite element simulation of a V-notched semi-circular specimen. It is shown that not only the singular terms, but also the "constants train field" significantly influence on tangential strain distribution and fracture initiation angle around the notch tip. The results of this paper can be used for standardization of the fracture in underwater structures containing V-notched components.

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