低速冲击下FMLs、铝板和复合材料的损伤对比

Comparison of Damage in FMLs,Aluminium and Composite Panels Subjected to Low-velocity Impact

为提高飞机结构的损伤容限和抗冲击性能,欧洲成功研制了多种纤维金属层板（FMLs）,并在具体机型结构上成功应用.对由玻璃纤维和2024-T3铝合金交替层压而成的FMLs进行落锤低速冲击试验,并与2024-T3铝合金板和准各向同性F300复合材料板进行了对比分析.FMLs完全穿透所需要的能量比2024 T3铝合金板和复合材料板分别高出约40％和6倍;在相同能量下,FMLs的背面裂纹长度比铝合金板短30％～50％.使用有限元法对FMLs动态冲击损伤过程进行了数值模拟,其中铝层采用延性损伤理论,纤维层采用Hashin失效准则,分析了层合板的动态冲击响应,总结了其损伤规律.数值结果与试验结果符合较好.

In order to improve the damage tolerance and anti-impact properties of aircraft structures, fiber metal laminates （FMLs） developed in Europe are successfully applied in commercial aircraft structures. In this paper, drop-weight low-ve- locity impact tests are performed on FMLs which consist of 2024-T3 aluminium alloy sheets bonded together by glass fiber prepreg. For comparison purposes, similar tests are conducted on monolithic 2024-T3 sheets and F300 quasi-isotropic com- posite panels. The penetration energy of the FMLs shows respectively about 40 % and 6 times higher than that of the 2024-T3 sheets and composite panels; and the back side crack length of the FMLs is 30%-50% shorter than that in the 2024-T3 sheets at the same level of impact energy. Finite element models are developed to simulate the impact response of the FMLs. Ductile and Hashin damage initiation criteria are used to simulate the aluminium and fiber failure mechanisms respec- tively. The dynamic response of the laminates is analyzed and the damage mode is summarized. The simulation results agree well with the experimental findings.