ON FFM/PFM FAILURE CRITERIA FOR METALS UNDERGOING SSY - NEW INSIGHTS AT V-NOTCHED TIPS [Keynote]
Zohar YosibashDogwood B
Structures made of steel alloys may fracture at V-notch tips at which a small plastic zone usually evolves. Failure criteria for predicting fracture loads for such quasi-brittle alloys, as a function of the V-notch opening angle are very scarce and have not been validated, to the best of our knowledge, by a set of experimental observations. Neither the FFM coupled criterion (FFMCC) for brittle fracture, nor two phase-field models (the classical AT1 for brittle materials and a ductile version) could predict the increase of the crack nucleation force observed in the four-point bend (4PB) experiments performed on AISI 4340 specimens as the opening angle increased. Extension of the FFMCC to account for the small plastic zone and further 4PB experiments on a new steel alloy (H13) are being considered to improve the failure criterion.