Method to Estimate the Plastic Zone Size and Opening Displacement at the Tip of Penny-Shaped Crack
Wu Xiangfa  Fan Tianyou
（Research Center of Materials Science, Beijing Institute of Technology, 100081)

Abstract: In this paper, a method is proposed to estimate the plastic zone size, by extending the Dugdale model to three-dimensional (3D) crack problems and the crack opening displacement (COD) at the tip of a sptatial penny-shaped crack by combining the Barenblatt-Dugdale model with the principle of 3D J-integral, then the relationship between J-integral and COD is obtained. Finally, the reliability of the estimation in this paper is testified by calculating the plastic zone size at the tip of a sptatial penny shaped crack embedded in an infinite elastic-perfect solid with nonlinear FEM and the unknown material constant is determined. The applicable domain of the Dugdale model is extended in this paper.
Keywords: Dugdale model, penny-shaped crack, 3D J-integral, plastic zone size, crack opening displacement.