TC4钛合金动态Ⅱ型裂纹扩展速度与加载速度的关系研究

为了确定TC4钛合金动态II型断裂实验中的起裂时间,计算TC4钛合金在发生II型断裂时塑性区能量吸收和裂纹扩展的速度,使用分离式霍普金森压杆装置对TC4钛合金进行动态II型裂纹扩展实验。采用高速数字散斑相关方法获取观测点处位移-时间历程曲线,确定了动态II型裂纹扩展的起裂时间,并计算出裂纹扩展速度。使用ABAQUS/Explicit软件建立有限元模型与实验结果进行同工况比对,在确认模型准确性后采用不同的加载速度研究II型加载条件下的裂纹扩展形式差异,计算出不同加载速度下的II型裂纹扩展速度,并得出加载速度与II型裂纹扩展速度的关系式。

Research on Relationship between Crack Propagation Speed of TC4 Alloy and Loading Speed under Mode Ⅱ Dynamic Loading

In order to ascertain the crack initiation time of TC4 in Mode II crack experiment, the energy absorption in plastic zone and the crack propagation speed are calculated. Split Hopkinson pressure bar (SHPB) is used to experiment upon Mode II crack propagation of TC4. High-speed digital speckle correlation method (HS-DSCM) is used to get displacement-time curve at a observation point, the Mode II crack initiation time of TC4 is determined, and the propagation speed of Mode II crack is calculated. A finite element model is established using ABAQUS/Explicit. The simulated results is compared to the experimental results. The propagation forms of crack at different impact velocities under loading condition are researched. Mode II crack propagation speeds at different loading speeds are calculated. Relation between loading speed and Mode II crack propagation speed is obtained.