Fatigue crack growth in different panels, made of AA6156 T6, was investigated experimentally and numerically. Three different types of panels were used, simple one, so-called base metal (BM), panel with 4 welded stringers and panel with 4 welded stringers and 3 welded clips. Experimental investigation indicated benefits of stringers, especially in respect to residual life, since the number of cycles were more than doubled (420 Kcyc vs 195 Kcyc for initial crack length 14 mm), but that was not the case for panels with clips (220 Kcyc). Experimental investigation was also performed on panels with longer cracks (75 mm) to check the effect of initial crack length in the case of BM and panels with 4 stringers, showing practically the same effect of stringers on residual life (95 Kcyc vs 50 Kcyc). Then, fatigue crack growth in panels was simulated numerically using xFEM. Numerical simulation indicated the same trend and effectiveness of stringers, with sufficient agreement with experimental results for BM and panels with stringers only. Anyhow in the case of clips panels with 4 stringers and 3 clips, number of cycles for panel with additional 3-clips was higher than for panel with just 4-stringer, (278 Kcyc vs 265 Kcyc), improving fatigue life for cca 5 %, contrary to experimental results.

用实验和数值方法研究了由 AA6156 T6 制成的不同面板的疲劳裂纹扩展。使用了三种不同类型的面板，简单的一种，即所谓的贱金属 (BM)，具有 4 个焊接纵梁的面板和具有 4 个焊接纵梁和 3 个焊接夹子的面板。实验调查表明纵梁的好处，特别是在剩余寿命方面，因为循环次数增加了一倍以上（420 Kcyc 对 195 Kcyc 初始裂纹长度 14 mm），但对于带有夹子的面板并非如此（220 Kcyc ）。还对裂纹较长（75 mm）的面板进行了实验研究，以检查初始裂纹长度对 BM 和具有 4 个纵梁的面板的影响，显示纵梁对剩余寿命的影响几乎相同（95 Kcyc 与 50 Kcyc） . 然后，使用 xFEM 对面板中的疲劳裂纹扩展进行了数值模拟。数值模拟表明纵梁具有相同的趋势和有效性，与仅具有纵梁的 BM 和面板的实验结果具有足够的一致性。无论如何，对于带有 4 个纵梁和 3 个夹子的夹子面板，带有额外 3 个夹子的面板的循环次数高于只有 4 个纵梁的面板（278 Kcyc 与 265 Kcyc），疲劳寿命提高了 5 % ，与实验结果相反。