Assessment of short fatigue crack closure behavior in Ti-6Al-4V alloy using 3D imaged-based CPFEM simulation

钛合金用于关键应用，例如飞机起落架，其承受严重载荷，因此需要优异的疲劳性能。因此，对占结构失效90%的疲劳损伤的理解至关重要。本研究的目的是表征三维疲劳短裂纹的张开和闭合行为及其对裂纹扩展速率的影响。目前，正在进行基于实际三维裂纹形状的裂纹闭合和张开行为的模拟。通过模拟，了解裂纹闭合是如何与微观结构发生关系的。从这一认识出发，可以设计钛的微观结构，开发出难以断裂的材料，从而确保安全性。

Titanium alloys are used in critical applications such as the landing gear of aircrafts which are subjected to severe loading and hence demand excellent fatigue properties. Therefore, the understanding of fatigue damage which accounts for up to 90% of failures in structures is critical. This study aims to characterize the 3D short fatigue crack opening and closing behavior and its influence on crack growth rate. Currently, simulation of crack closing and opening behavior based on the actual 3D crack shape is being conducted. From the simulation, know how crack closure is generated in relation to the microstructure. From this understanding, it is possible to design the microstructure of titanium to develop materials which are difficult to fracture, hence guaranteeing safety.