Stability of composite stiffened panels under compression

Experiments for compression stability analysis were conducted on composite stiffened panels SC-1 and SC-2 with different T-stringer lay-ups. A proposed engineering method was introduced to predict the buckling load and the least post-buckling carrying capability, and finite element analysis with eigenvalue method and arc-length method were carried out to investigate the bucking load, buckling mode, and post-buckling carrying capability. Experiment results show that SC-1 with more stringer ply-ups possess the higher local bucking strain of skin and the higher buckling load of the panel, and SC-2 can sustain a post-buckling carrying capability of 2.4 times of buckling load without material damage and stringer-skin debonding. The engineering method and eigenvalue method acquire the buckling loads of the panels with errors of -9.3% and -2.8% respectively, and the minimum post-buckling carrying capability of SC-2 is 2.09 times of experimental buckling load by engineering method. The errors of buckling loads by arc-length method are less than 1% for both SC-1 and SC-2, and the buckling modes and distortion are well trailed with load increasing.