三维广布裂纹应力强度因子求解

 针对飞机结构表面由于腐蚀、疲劳等原因存在三维广布裂纹，相邻裂纹在疲劳载荷作用下相互影响、相互促进，从而加速了结构破坏。为了定量描述相邻裂纹间的影响规律，采用参数化有限元方法，结合1/4节点位移方法和循环迭代算法，对一有限厚矩形板表面有两个半椭圆表面裂纹在拉伸载荷作用下进行了求解，得到两裂纹在共面、中心叠加平行和斜平行3种位置状态时的应力强度因子和应力变化图，计算结果为含三维广布裂纹飞机结构的剩余强度和疲劳寿命确定提供了理论依据。

Solution for Stress Intensity Factors of Three Dimensional Widespread Cracks

Three dimensional widespread cracks exist on the surface of aircraft caused by corrosion,fatigue,and other potential damage mechanisms,and the interaction in adjacent cracks accelerate the damage of structures under fatigue loading.In order to quantitatively describe the rules affecting adjacent cracks,a rectangular plate of finite thickness under remote tensile load with two semi-elliptical surface cracks of different geometric dimensions in close vicinity is used as a model,and a parametric finite element method along with the 1/4 point displacement method and circulatary iterative algorithm are used to calculate the stress intensity factors and stress changing pictures of these two cracks in coplanar,center overlapped parallel and inclined parallel situations.The results may provide a theoretical reference to determine the residual strength and fatigue life for aircraft structures with three dimensional widespread cracks.