Buckling and post buckling investigation of stringer stiffened CFRP panels under in-plane loading - experimental investigations

Abstract

In this contribution, results obtained from buckling and post buckling tests of stringer stiffened panels are presented. This work aimed to contribute to establish an advanced design scenario in which skin buckling is allowed clearly below limit load (LL) so that the considerable load carrying capacity reserves in the post buckling regime of a stringer stiffened panel are exploited. This finally leads to the reduction of structural weight. In this context, experiments of two nominal identical T-stringer stiffened CFRP panels are described and discussed. One panel was tested statically until collapse while the second one was subjected to cyclic loading. Prior testing, the test structures were assessed by NDI. During the experiments, additional to the load shortening data and strain gauges, DIC (ARAMIS) as well as thermography measurements were utilized to gather information about the structural response. Furthermore, the concept to extend the existing test facility for the buckling and post buckling investigation of curved stiffened panels under combined axial and shear loading is described. In-plane shear as well as combined axial and shear loading are complementary to pure axial loading predominant and important load cases within buckling and post buckling investigations. With this extension of the buckling test facility a wide range of in-plane loading scenarios can be covered.