Study of stress intensification factor generated by milling operations on brittle materials

Milling operation on brittle materials usually introduces defects which can behave as cracks around the notch generated in parts subjected to tension or bending. This study evaluates a case where the Stress Concentration Factor (K(t)) is generated due to the presence of the double notch. The studied model is based on a deep U-notch, which appears at the root of a larger circular notch (R(circ) >> r(U)). The Finite Element Method (FEM) had been used to simulate all the studied cases. The K(t) were determined by FEM and compared with values from literature, if they were available, and there was an acceptable agreement, no larger than 6.76%. It was also possible to determine when the semi-circular notch does not exert more influence on the severity of the defect, and the fracture parameters of the material were only controlled by manufacturing defects.