The Mechanical Response of Corrugated Core Sandwich Columns

This study presents analytical, numerical and experimental protocols to characterize the in-plane loading response of metallic corrugated core sandwich structures.;The failure mechanisms for the in-plane loading of a corrugated core sandwich column have been identified and include macro buckling, shear buckling and face wrinkling. Analytical formulae are developed for these mechanisms and used to create failure mode maps. Failure maps are created for corrugated core columns composed of SAE 304 stainless steel and aluminum 6061-T6.;Experimental testing has been carried out to validate the analytical predictions. Using the analytically derived failure maps, corrugated core columns are designed to experimentally probe each failure regime and the results are compared to the predictions. Two fabrication methods are employed to create samples. Stainless steel sandwich columns are fabricated via a conventional method in which the core is constructed using a bending technique and joined to the face sheets through a brazing process. Aluminum columns are fabricated using a novel extrusion process for sandwich structures that creates the core and face sheets as a single continuous piece. Finite element simulations are also developed to model the in-plane compression of corrugated sandwich columns and compared to the measured and predicted responses.;The results demonstrate that the analytical predictions accurately capture both the critical failure load and failure mechanism of corrugated core columns under in-plane loading. The results also highlight the influence of both local and global boundary conditions on the column response. It is found that the local boundary conditions imposed by the core on the face sheets are a function of both the core ligament slenderness and the ratio between the face thickness and core ligament thickness. For the samples tested, a transition to a fixed local boundary constraint occurs at a core relative density of rho=8%.;Lastly, a minimum mass optimization procedure is carried out to compare the performance of corrugated core columns to competing axial load bearing structures. The results show that corrugated core columns compare favorably with competing pyramidal core and hat-stiffened panel designs and are a viable alternative for in-plane load bearing applications.