Impact of coupling a constitutive model with the ductile fracture criterion on the computational predictability of wrought Inconel 718

Abstract

Prediction of ductile fracture is essential for designing of components and structures. Local uncoupled and local as well as non-local partially coupled models are compared for tensile tests of specimens made from nickel-based superalloy Inconel 718 with varying geometries: a smooth cylindrical specimen, notched cylindrical specimens with R2.5 and R8 and a flat plate specimen. The ductile fracture criterion was calibrated using a hybrid experimental–numerical approach, with the non-local part based on strain in the loading direction measured optically on a notched specimen. Models are compared with respect to force responses, moment of crack initiation and appearance of final failure. All numerical simulations, including a mesh sensitivity study, were performed in LS-DYNA software using the Newmark implicit time integration scheme. Globally, the non-local approach does not seem to be ready for solving bulky spatial problems.