Post-buckling test and numerical analysis of multi-spar wing box

The bending static experiments and FEM were used to study the post-buckling performance of a composite thick-skin multi-spar wing box. The well agreements of the load-displacement curves between experiment and FEM show the FEM modeling is credible. Based on this FEM model, the post-buckling behaviors of the wing box under two different loads: concentrate and press load, were investigated. The buckling behaviors were determined by tracing the load-deflection curves using non-linear arc-length method. Numerical results present the critical load, buckling deformation behaviors, the stress distribution and the destroy process.