Notch and Fracture Mechanics-Based Assessment of Multiaxial Fatigue Thresholds of Defects and Sharp Notches in Metallic Materials

This investigation focuses on the constant amplitude (CA) multiaxial fatigue limit of components made of metallic materials weakened by defects, cracks, and sharp U- and/or V-notches. To estimate the multiaxial fatigue thresholds of plain, sharply notched, and cracked materials and defects, a novel theoretical framework based on the well-known averaged strain energy density (SED) criterion is proposed, which extends the Atzori–Lazzarin–Meneghetti (ALM) diagram to multiaxial loading. The proposed design equations are validated against 128 experimental multiaxial fatigue limits, taken from the literature.