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针对于某通用飞机防火墙在重着陆后检查到的皱褶变形,利用有限元方法分析了该结构在较大载荷情况下的屈曲行为。分析结果与真实结构的破坏形式非常接近。当飞机重着陆时,前起落架的载荷向防火墙传递超过4488N时,防火墙结构将开始发生失稳破坏,失稳后结构承载能力并未消失,防火墙可以达到的最大能力约为8628N。超过该载荷,防火墙结构将发生全面的皱褶变形,并可能会对相邻其它传力路径的结构造成损伤。对不同初始缺陷的结构分析发现不同的初始微小缺陷对结构的承载能力影响非常小。最后,通过对防火墙厚度的分析发现增加厚度0.1mm,重量增加25%(约0.3kg),将使承载能力提升约50%,为此结构的修理维护及可能的设计修改提供了重要的参考。
Aiming at the wrinkle deformation of a common aircraft firewall after heavy landing, the buckling behavior of the structure under large load is analyzed by finite element method. The result of the analysis is very similar to the destruction of the real structure. When landing the aircraft landing, the load of the nose gear over the firewall to pass more than 4488N, the firewall structure will begin to destabilize the failure, instability after the structure does not disappear, the maximum capacity of the firewall can reach about 8628N. Exceeding this load, the firewall structure undergoes extensive fold deformation and may damage the structure of other adjacent force paths. The structural analysis of different initial defects found that different initial tiny defects have little effect on the bearing capacity of the structure. Finally, through the analysis of the thickness of the firewall, it is found that increasing the thickness by 0.1mm and weight by 25% (about 0.3kg) will increase the carrying capacity by about 50%. This provides an important reference for the repair and maintenance of the structure and the possible design modifications.