航空复合材料加筋板压缩屈曲及后屈曲性能

开展了航空复合材料加筋板压缩试验,得到了加筋板的屈曲载荷、破坏载荷及破坏模式.加筋板平均屈曲载荷和平均破坏载荷分别为587.5,968.25kN,后者是前者的1.65倍,表明加筋板在压缩载荷下存在较强的后屈曲承载能力,其破坏模式主要是筋条的脱黏、断裂以及壁板的撕裂,破坏位置通常在加筋板中部.应用有限元软件得到了加筋板的屈曲载荷、破坏载荷及后屈曲损伤过程,其中屈曲载荷、破坏载荷与试验结果较吻合,误差分别为-9.97%和8.45%,验证了有限元模型的有效性.研究了加筋板纤维和基体出现损伤的先后顺序,结果表明在后屈曲过程中加筋板纤维先于基体出现损伤,尤其是筋条中部纤维的损伤最为严重,加筋板破坏之前基体基本不存在损伤.

Buckling and post-buckling performance of aeronautic composite stiffened panel under compression

Compression experiment on aeronautic composite stiffened panel was conducted to study the buckling load, failure load and failure modes. From the experimental results, the average failure load(968.25kN) was 1.65 times the average buckling load(587.5kN),indicating that the composite stiffened panel had a relatively high post-buckling bearing ability. Its primary failure modes are the debonding, crack of stiffeners and the splitting of panel. The failure section is usually located in the middle part of composite stiffened panel. The buckling load, failure load and post-buckling damage progress of stiffened panel were analyzed by using finite element software. Buckling load and failure load obtained were in well agreement with the experimental results. Compared with experimental results, the errors were -9.97% and 8.45% respectively, indicating the validity of the finite element model. Sequence of damage occurring in fiber and matrix was studied. The simulation results show that in post-buckling progress, the damage of fiber occurs earlier than that of the matrix, and especially the damage of fiber in middle part of stiffeners is most serious. There is little damage in matrix before the failure of composite stiffened panel.