飞机薄壁结构面外载荷下三维疲劳裂纹扩展仿真分析

飞机结构中部分薄壁结构在服役中不可避免地承受面外弯曲载荷，这对飞机的安全性有显著影响。采用FRANC3D 和ABAQUS 联合仿真的方法，对薄板受弯曲载荷作用下的疲劳裂纹扩展行为开展研究，分析边界约束强度和初始裂纹形状对此类疲劳裂纹扩展模拟的影响，并评估仿真方法的适用性。结果表明：模拟中施加较弱的边界约束，会使计算的应力强度因子增大；相比于初始非孔边的表面裂纹，初始孔边角裂纹在裂纹扩展初期扩展速率更高；现有的FRANC3D 和ABAQUS 联合仿真的方法在模拟面外弯曲载荷下薄板孔边裂纹扩展时，存在受压面裂纹无法扩展的问题。

Three-dimensional fatigue crack propagation analysis of aircraft thin-walled structures under out-of-plane loading

Some thin-walled structures in aircraft structures inevitably bear out-of-plane bending, affecting the safety of aircraft significantly. The FRACN3D-ABAQUS simulation was carried out in this paper to understand this issue. Effects of boundary restraint and initial crack shape on this kind of fatigue crack propagation were studied. The applicability of the simulation method was evaluated. Following results were obtained: applying the crack surface contact and weaker boundary constrains in simulations will increase the calculated Stress Intensity Factor (SIF); the initial hole corner crack has a higher crack propagation rate than the initial surface crack around the hole; the FRACN3D-ABAQUS simulation method cannot simulate the crack propagation in the compressed surface, where the crack is unable to propagate.