不同防护形式复合材料板雷击损伤分区特性

基于A+B+C+D 4种标准雷电流波形的联合作用,开展了不同防护形式复合材料板雷击试验。考虑放电通道物理特性,分析放电通道与复合材料表面间的作用过程,将复合材料表面损伤区域分解成初始附着区、附着传导区、附着扩展区、二次附着区和扫掠损伤区,并对未防护基准件、局部喷铝、全喷铝防护件及铜网防护件4类板的各区域进行了损伤特性分析。结果表明:复合材料表面损伤是强电磁场条件下放电通道热电物理特性与复合材料表面热电特性及电荷分布的共同作用结果;复合材料表面铝层喷涂方式、厚度以及均匀程度均影响表面损伤的对称性和损伤分区特性;铜网防护造成复合材料板表面粗糙使得表面损伤分区复杂;表面电荷累积特性和分布的均匀程度直接影响二次附着区和扫掠损伤区的分布;复合材料表面雷击损伤包括纤维升华、断裂、起毛,基体炭化熔融、烧蚀,材料分层、剥落以及防护材料的熔融汽化和断裂等。分析结果可以用于复合材料雷击防护定性设计。

Damage zoning characteristics of composite laminates with different protections subjected to lightning strike

Lightning strike tests of composite laminates with different protections were conducted based on the combining strikes of four standard waveforms A+B+C+D. The interaction procedure between the lightning channel and composite laminate surface was analyzed, and the surface damage area of composite was divided into initial attachment area, attached conduction area, attached expansion area, reattachment area and swept damage area with respect to the physical characteristics of lightning channel. And the damage characteristics were analyzed for four types of laminates: unprotected reference specimen, partial and full-scale spraying aluminum specimens, and copper grid specimen. The results show that the surface damage of composite is induced by the interactions of thermo-electrical physical properties of lightning channel, surface thermo-electrical properties of composites, and charge distribution in strong electromagnetic field. The characteristics of symmetry and zoning of damage area on surface of composites are affected by spraying shape, thickness and homogeneity of aluminum layer. The rough surface of composite laminates induced by copper grid protection leads to the complexity of surface damage zoning. The accumulation characteristic and homogeneity of distribution for the induced charge on surface of composite laminates are the direct reasons for distributions of reattachment area and swept damage area. The primary damage forms of composites subjected to the lightning strike include fiber sublimation, rupture and fuzzing, the matrix charring melting and ablation, the delamination and detaching of materials, and the melting, vaporization and breakdown of protective materials. The analysis results can be applied to the qualitative design for lightning protection of composites.