Stress Concentration Analysis of Round and Flat Test Specimen with Fillets

Abstract

In this study, the interaction effect among cracks and fillets in a round and flat test specimen under tension is analyzed using the body force method. The stress field induced by a ring force acting in the radial and axial directions in an infinite body and a point force in a semi-infinite plate are used as a fundamental solution to solve these problems. The stress concentration factors of the fillet in a stepped round bar are systematically calculated under various geometrical conditions. Through the comparison of the present results with those of previous research studies, it is found that the Peterson's stress concentration charts based on photoelastic tests give stress concentration factors underestimated by about 13%. The stress distribution at the narrow section of the test specimen without cracks and the stress intensity factor of the test specimen with cracks are systematically investigated and the geometrical condition whereby the interaction effect between the fillet and crack disappears is discussed.