Numerical simulation research on crack propagation of plane steel

Abstract

There are still two deficiencies in the study of crack propagation in plane steel. One is that there are few studies on the theory of crack cracking and the cracking criterion from the strain field at the crack tip; the other is that there are few studies using the block discrete element method to explore the crack propagation. In view of the above two points, this paper proposes a strain strength criterion to explain the extension of tensile cracks and shear cracks in steel. This strain strength criterion assumes: (1) Tensile cracks grow along the direction of the maximum principal strain. When the principal strain γ reaches a critical value, the tensile cracks begin to grow; (2) Shear cracks grow in the direction of the most dangerous stress state. When the Mohr circle exceeds the Mohr Coulomb failure line, the shear crack starts to expand. In addition, this paper applies the strain strength criterion to the block discrete element method to simulate the macro-mechanical response characteristics of steel under load and the propagation and evolution process of cracks. It is shown (1) the stress-strain curve appears elastic, stagnant, fluctuating, and falling back, etc. The basic law, and (2) the characteristics of stable and unstable growth of cracks during the whole loading process.