Cracks starting at surfaces will grow under fatigue loading conditions both along the surface and in the thickness directions of the component geometry. In those cases where the crack grows through the thickness, the fatigue crack may transition to a corresponding through crack geometry. While the fatigue crack growth behaviour of both the surface flaws and complete through cracks are well understood, the method for modelling the process by which they transition from one to the other is not. This paper seeks to bring greater clarity and understanding to the transition process by implementing a transition method and developing the associated codes and equations to do so based on careful consideration of boundary conditions, experimental data, and finite element simulations.

中文翻译：

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表面缺陷到贯通裂纹的过渡建模

从表面开始的裂纹将在疲劳载荷条件下沿表面以及部件几何形状的厚度方向增长。在裂纹扩展到整个厚度的情况下，疲劳裂纹可能会过渡到相应的贯通裂纹几何形状。虽然已经很好地理解了表面缺陷和完全贯穿裂纹的疲劳裂纹扩展行为，但还没有为它们从一个过渡到另一个过渡的过程建模的方法。本文旨在通过仔细考虑边界条件，实验数据和有限元模拟，通过实施过渡方法并开发相关的代码和公式来使过渡过程更加清晰和理解。