The major challenges facing engineers while fabricating high precision components from carbon fiber reinforced polymers (CFRP) especially when using an abrasive waterjet (AWJ) include the predominant interlaminar delamination and tapered kerfs. Therefore, in the present work, a comprehensive 3-D transient fluid-structure interaction (FSI) model is developed and numerically simulated to investigate mechanisms leading to delamination and hole-geometric defects while drilling autoclave cured aerospace grade multidirectional CFRP laminates. The FSI model comprised a two-way interaction between the computational fluid dynamics (CFD) flow model and structural finite element (FE) model. The CFD model explored the dynamic jet characteristics while impinging the anisotropic CFRP surface. The resulting forces from the CFD domain acted as loads in the transient FE model to predict the initiation of cracks and delamination. Subsequently, extensive experiments were conducted to validate the proposed numerical model. The results illustrated that during abrasive waterjet drilling of CFRP, delamination was initiated by the hydraulic impact as the abrasive waterjet penetrated the workpiece. Additionally, the study revealed that an increase in abrasive waterjet pressure and abrasive particle size resulted in a higher inter-ply debonding and crack propagation. Correspondingly, an increase in the standoff distance (SoD) resulted in reduced crack propagation and delamination. Further, the liquid-solid interface exhibited asymmetric cracks. The present findings not only provide requisite guidelines to achieving high-precision drilling of multidirectional CFRP but also provide technical guidelines to improving the performance characteristics of the abrasive waterjet machining (AWJM) process.

工程师在用碳纤维增强聚合物（CFRP）制造高精度部件时面临的主要挑战，尤其是在使用磨料水射流（AWJ）时，主要是层间分层和锥形切口。因此，在本工作中，开发了一个综合的3-D瞬态流体-结构相互作用（FSI）模型，并对其进行了数值模拟，以研究在高压釜固化的航空航天级多方向CFRP层压板钻孔过程中导致分层和孔几何缺陷的机理。FSI模型包括计算流体动力学（CFD）流动模型和结构有限元（FE）模型之间的双向交互作用。CFD模型探索了撞击各向异性CFRP表面时的动态射流特性。来自CFD域的合力在瞬态有限元模型中充当载荷，以预测裂纹和分层的产生。随后，进行了广泛的实验以验证所提出的数值模型。结果表明，在CFRP磨料水刀钻孔过程中，当磨料水刀穿透工件时，由于水力冲击而开始分层。此外，研究表明，磨料喷水压力和磨料粒度的增加导致层间剥离和裂纹扩展更高。相应地，隔离距离（SoD）的增加导致裂纹扩展和分层减少。此外，液-固界面显示出不对称的裂纹。