Postbuckling of Composite Airframe Structures: Closed-Form Approximate Solutions

In this contribution, the postbuckling behaviour of imperfect rectangular composite plates under compression is treated in a closed-form analytical manner. Based on rather simple shape functions for the postbuckling deflections and the plate imperfections, the requirement for compatibility of the membrane strains leads to an explicit solution for Airy’s stress function. The equilibrium condition in the out-of-plane direction is not fulfilled explicitly, but rather in an integral sense using a Galerkintype formulation, leading to an approximate closed-form solution for the postbuckling deflections. Eventually, rather simple closed-form approximate solutions for all postbuckling state-variables can be derived that can be used conveniently in engineering practice. The quality of the closed-form solution is established by comparison with the results of other authors.