老龄化结构表面裂纹间相关性分析与研究

采用有限元方法对表面含有两个不同大小半椭圆裂纹的有限厚矩形板在拉伸载荷作用下进行参数化求解，得到两裂纹取不同尺寸和位置坐标时附属裂纹(尺寸较小裂纹)对主导裂纹(尺寸较大裂纹)前沿参考点($theta= 0, pi/2, pi $)处的应力强度因子的影响系数$beta$, 然后结合神经网络技术建立了相邻裂纹尺寸和位置参数到主导裂纹前沿点处$beta$的多变量非线性映射关系.

RELATIVITY ANALYSIS AND RESEARCH ON THE SURFACE CRACK IN AGING STRUCTURE

When two or more surface cracks are present on an agingstructure the structure damage is accelerated. A finite thickness plateunder remote tensile surface traction with two semi-elliptical surfacecracks of different geometric dimensions and configurations in closevicinity is used as a model. To calculate the effect of vicinity crack onthe 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 cracksize is obtained through parametric analysis. After getting the stressintensity factor $K$ and $K'$ (where $K$ and $K'$ are the stress intensity factor with and without interaction of the crack inthe 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 andlocation with effect factor $beta$by Neural Network. The result provides theoretical reference in practice toanalyze the aging structure with multiple surface cracks.