Simulation of impact energy in functionally graded steels by mechanism-based strain gradient plasticity theory

Charpy impact energy of functionally graded steels composed of graded ferritic or austenitic layers which were produced by electroslag remelting in both crack divider and crack arrester configurations has been modeled by finite element method. The yield stress of each layer was related to the density of the dislocations of that layer and by assuming Holloman relation for the corresponding stress–strain curve, tensile strength and tensile strain of that layer were determined. Cubic elements were joined together to build the standard Charpy impact specimen. The data used for each cubic element in finite element modeling was the predicted stress–strain curve obtained from strain gradient plasticity theory. After applying the impact loading, a relatively good agreement between experimental results and those obtained from simulation was observed.