Impact direction is one of the critical factors affecting the waterdrop erosion behavior of materials. In this paper, rain erosion damage behavior of a typical carbon fiber reinforced polymer (CFRP) laminate is investigated as a function of the impingement angle (0° as normal impact and 15°, 30°, 45° as oblique impact deviated from the normal) and the relative fiber orientation (parallel PA and perpendicular PE to the fiber direction of the surface layer) under the waterjet velocity of 320 m/s and the impact frequency of 50 Hz via a pulsating waterjet erosion test rig. After continuous impact of multiple waterjets, the typical damage of CFRP laminates is mainly composed of the central erosion crater and the upheaval of the surrounding surface layer. The onset and evolution of damage are mainly driven by the shear action of lateral jetting and stress concentration of hydraulic penetration exerted at the surface irregularities. There is no significant difference in the damage modes between the normal and oblique impacts, except for the asymmetric distributions of matrix cracking in PA-orientation and delamination in PE-orientation caused by the angle inclination. With the impingement angle increasing, the volume loss and erosion depth decrease while the incubation period increases mainly due to the decreases of water hammer pressure and contact area. The PA-orientation can cause lower incubation period and larger erosion mass loss than PE-orientation before the surface ply is penetrated, with the underlying mechanism related to the distinct tensile properties of CFRP laminates along longitudinal and transversal directions and the asymmetric properties of fiber–matrix interface. According to the fitting results of erosion curves, it is possible to describe the incubation period and the erosion rate of CFRP laminates under oblique impact using a two-branch equation, and Springer model can give reasonable prediction for the average incubation period and PA-orientation erosion rate of a certain oblique impact occasion with known 0° impact erosion results.

中文翻译：

---

脉动水射流正向和倾斜冲击侵蚀 CFRP 层合板的损伤演化

冲击方向是影响材料水滴侵蚀行为的关键因素之一。在本文中，研究了典型碳纤维增强聚合物（CFRP）层压板的雨水侵蚀损坏行为作为冲击角度的函数（0°为法向冲击，15°、30°、45°为偏离法向的倾斜冲击） ）以及脉动水射流侵蚀试验台在水射流速度320 m/s、冲击频率50 Hz下的相对纤维取向（平行于表层纤维方向的PA和垂直于PE的方向）。经过多次水射流的连续冲击后，CFRP层合板的典型损伤主要由中心侵蚀坑和周围表层隆起组成。损伤的发生和演变主要是由横向喷射的剪切作用和施加在表面不规则处的水力渗透的应力集中驱动的。除了PA方向的基体开裂和PE方向的分层由于倾斜角度引起的非对称分布外，正向冲击和倾斜冲击的损伤模式没有显着差异。随着冲击角度的增大，体积损失和侵蚀深度减小，而潜伏期增加，主要是由于水锤压力和接触面积的减小。在表层被穿透之前，PA 取向比 PE 取向可以导致更短的潜伏期和更大的侵蚀质量损失，其潜在机制与 CFRP 层压板沿纵向和横向的独特拉伸性能以及纤维的不对称性能有关。矩阵接口。根据侵蚀曲线的拟合结果，可以用二分支方程描述CFRP层合板在倾斜冲击下的潜伏期和侵蚀速率，Springer模型可以对平均潜伏期和PA取向给出合理的预测已知0°冲击侵蚀结果的一定倾斜冲击场合的侵蚀速率。