Application of the Evolution Strategy for Assessment of Deformation and Fracture Response of Ferritic Steel During Its Manufacturing

ABSTRACT

In this article, the developed numerical techniques for assessment of deformation and fracture response of ferritic steel during its manufacturing are considered. Because microdefects of ferritic steel are thought to nucleate at second-phase particles, the formulated strategy for evaluating these particles uses standardized experimental fracture tests with micromechanical FEM simulations of microdefect evolution in the material. The evolution of the microdefects is described by an enhanced Gurson-type model incorporating effects of the microvoid aspect ratio. An estimate of the objective function for material parameters of the Gurson-type model is provided by the Kalman filtering technique. Their best fit set of the material parameters is established by the search scheme of the evolution strategy according to the density, size, and spatial distribution of second-phase particles in the material. Some examples are presented to demonstrate that the evolution strategy can be used to optimize important processes of steel manufacturing in the context of strength and toughness of critical parts.

Key Words:

• Enhanced Gurson-type model incorporating effects of the microvoid aspect ratio
• Evolution strategy for the inverse search scheme
• Kalman filtering technique
• Micromechanical FEM-simulations
• Nonlocal damage mechanics

ACKNOWLEDGMENT

The author thanks Prof. N. Chakraborti and the reviewers of this article for their helpful comments.