复合材料板穿孔损伤贴补修复及其对掠入射电磁波回波特性的影响

Patch repair of perforation damage in composite laminates and its influence on the echo characteristics of grazing incidence electromagnetic waves

  • 摘要: 第五代飞机中大量应用碳纤维增强复合材料,其对隐身性能的极致追求使得复合材料蒙皮的损伤修复不仅要考虑强度恢复率还要考虑隐身性能的修复情况。本文针对蒙皮复合材料板的穿孔损伤开展力学和隐身性能的损伤评估工作,并探索有效的单面贴补修复方法。结果表明,穿孔损伤对复合材料拉伸强度有显著影响,对于宽50 mm的准各向同性复合材料板,10 mm直径的穿孔即可使强度下降超40%;穿孔对掠入射下的雷达散射截面(RCS)同样影响显著,直径10 mm的穿孔可使2 mm厚蒙皮0°~15°入射角下的平均RCS增加4.85 dBsm。复合材料穿孔损伤的贴补修复效果与补片形状有关,其中矩形补片无法同时满足强度和隐身性能恢复的需求;菱形补片虽可有效降低RCS,但会大幅降低拉伸强度修复效果;补片端部斜削的方式可同时满足力学强度和隐身性能修复要求。对含有10 mm穿孔损伤的2 mm厚的准各向同性复合材料板,采用1∶60端部斜削处理的补片进行贴补修复,在隐身性能极大程度恢复的情况下,强度恢复率可达81.54%。

     

    Abstract: In fifth-generation aircraft, carbon fiber reinforced polymer composites are extensively utilized. The pursuit of ultimate stealth performance necessitates that repairs to composite skin damage consider not only the restoration of mechanical strength but also the recovery of stealth capabilities. This paper focuses on the damage assessment of mechanical and stealth performance for perforation damage in composite skin panels, and explores effective single-patch repair methods. The results indicate that perforation damage significantly affects the tensile strength of composite laminates. For a quasi-isotropic composite panel with a width of 50 mm, a 10 mm diameter perforation can reduce the strength by more than 40%. Perforation also has a substantial impact on the radar cross section (RCS) under grazing incidence; a 10 mm diameter perforation can increase the average RCS of a 2 mm thick skin by 4.85 dBsm for incidence angles between 0° and 15°. The repair effectiveness of patch repair for composite perforation damage is related to the patch shape. Rectangular patches fail to simultaneously meet the requirements for strength and stealth recovery. Although diamond-shaped patches can effectively reduce RCS, they significantly compromise the restoration of tensile strength. The tapered-end patch design satisfies both mechanical strength and stealth performance restoration requirements. For a quasi-isotropic composite panel with a 10 mm diameter perforation and a thickness of 2 mm, using a patch with a 1∶60 taper ratio for patch repair achieves a strength recovery rate of 81.54%, while substantially restoring stealth performance.

     

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