RELATIVITY ANALYSIS AND RESEARCH ON THE SURFACE CRACK IN AGING STRUCTURE
老龄化结构表面裂纹间相关性分析与研究

When two or more surface cracks are present on an aging structure the structure damage is accelerated. A finite thickness plate under remote tensile surface traction with two semi-elliptical surface cracks of different geometric dimensions and configurations in close vicinity is used as a model. To calculate the effect of vicinity crack on the reference crack, the three-dimensional finite element method is used. Firstly the relation between stress intensity factor, at reference point ($\theta = 0, \pi/2, \pi )$ on reference crack front, with the crack size is obtained through parametric analysis. After getting the stress intensity factor $K$ and $K'$ (where $K$ and $K'$ are the stress intensity factor with and without interaction of the crack in the vicinity respectively) the effect factor $\beta$ of vicinity crack to reference crack is calculated where $\beta =K'/K$. Finally the nonlinear relation is set up between crack dimensions and location with effect factor $\beta$ by Neural Network. The result provides theoretical reference in practice to analyze the aging structure with multiple surface cracks.