The Numerical Analysis Of The Stress Intensity Factors For The Body With Surface Crack And Surface Semi-Spherical Cavity

Due to the stress concentration for the presence of the hole or the other surface flaw (for example, semi-sphere cavity or cylinder cavity) in the component, cracks are likely to initiate at the hole or the surface flaw under the action of fatigue loading. It is well known that the presence of the hole or the surface flaw gives rise to the stress concentration and that the presence of the surface crack causes stress and strain singularities. Thus the stress concentrations and the stress singularities acting togethor complicate the analysis of the structure.And it is fair to say that the study of the cracked body with the other surface flaw is of important significance to theory and practice. So the cracked elastic body with semi-spherical cavity (short for the crack problem with surface flaw) is considered and the stress intensity factors(SIFs), which is a critical parameter in the analysis of a cracked body, is studied by numerical method. The model considered here may be a more representative model when it is compared to the well-known surface semi-elliptical crack.Based on research of the surface crack in existence, the present paper, in which the relevant models are selected and analyzed by FRANC3D which is a fracture analysis software developed by a fracture investigation group of Cornell University(CFG), arrives at the following conclusions:(1) When R/t≤0.2, R/t≤0.2 and R/H≤0.2, the cracked body can be accepted as infinite. And when R/t(?)0.2, R/W(?)0.2, R/H(?)0.2, we can receive it as finite( R is the radius of the surface crack. W is the half width of the cracked body. t is the thickness and H is the half length of the cracked body).(2) The stress intensity factors(SIFs) in the crack front decreases with the increase of the distance from the upper free surface regardless of the cracked body type(infinite or finite).(3) The maximum stress intensity factors is a function of R/r (r is the radius of the surface semi-spherical cavity) for the infinite cracked body. And the surface semi-spherical cavity doesn't always amplify the stress intensity factors(SIFs) when it is compared to the stress intensity factors for the...