04.1 - Aerospace Grade Materials, Structural Analysis, Fatigue and Damage Tolerance

HIGH-VELOCITY DROPLET IMPACT STUDIES ON C/SIC AND C/C COMPOSITES

Y. Yue¹, R. Zhao¹, B. Wang¹, Y. Li, Shaanxi Key Laboratory of Impact Dynamics and Engineering Applic, China; ¹School of Aeronautics, Northwestern Polytechnical University, China

Rain erosion is a potential hazard for supersonic vehicles, with severe damage to materials that may be impacted by raindrops. C/SiC composite materials and C/C composite materials are widely employed in high-speed aircraft due to their excellent high-temperature and mechanical performance. The rain erosion issues associated with these two materials hold significant research significance.rnIn this paper, a series of impact tests of 260–572 m/s are carried out on a 3 mm-thick 2D C/SiC composite specimen and 3 mm-thick 3D C/C composite specimen using a single impact waterjet apparatus. The typical morphology of C/SiC specimen and C/C specimen are obtained by single jet impact test. Observations using optical microscopy, SEM, and X-CT revealed that damage to both materials included matrix cracking and loss, delamination, and fiber fracture. The study found that with an increase in droplet impact velocity and diameter, the extent of damage significantly increased. When the droplet impact velocity reached 570 m/s, a change in the damage pattern occurred. Stress waves generated reflected tensile waves on the specimen's backside, resulting in noticeable fiber fracture and matrix loss in both materials. Three-point bending tests on the post-impact C/C composite materials showed a significant drop in bending resistance after impact at 570 m/s, indicating that backside damage affected the material's mechanical performance.rnUnder the multi-droplet impact, the stress wave interaction is enhanced, and the internal damage of the specimen is severe, showing a funnel-shaped damage. The study found that the multi-drop impact process for both materials is a process of cumulative damage expansion. Moreover, the C/SiC specimen is penetrated after 5 drops of impact. Quasi-static tensile tests were employed to quantify the post-impact strength of the specimen, during which the digital image correlation (DIC) method was used t

Sorry, there is no file available for this paper.