Research on multiaxial notch fatigue life of additively manufactured 316L considering mean stress and multiaxial stress state

Abstract

Abstract Fatigue tests were performed on Additively Manufactured (AM) 316L steel. Then, a new energy based multiaxial notch fatigue life model was proposed, in which a virtual strain energy that can reflect the multiaxial effect of stress and the mean stress was used as the damage parameter, and a notch coefficient was used to modify the notch root damage parameter. The notch coefficient was defined as the area ratio between the normalized strain energy curves of the notch and the smooth specimen. The proposed approach was validated by the experimental data of AM 316L steel, and was compared with the theory of critical distance (TCD), as well as the local strain energy density method (SED). The results indicate that nearly 80% of the predicted data fall within the factor of 3 scatter band for the proposed method. The accuracy of the proposed method is better than the other two methods, and can be used for different notch geometries and loading paths.