Flexural analysis of second-order corrugated composite cores: Experimental, numerical, and theoretical studies

Corrugated cores with structural hierarchy are one types of advanced cores that inspired from nature. In this work, the bending behavior of a second order, hierarchical corrugated structure has been analyzed. Experimental tests are implied to sandwich panels with both first- and second-order corrugated core by means of three-point bending test. For trapezoidal core, finite element model is provided and numerical results are validated by experimental results. Then, the validated properties are used to model sandwich panel with first- and second-order corrugated cores. To make a correct comparison, out-of-plane shear modulus of mentioned cores is calculated. Further to classical approach of ASTM7250, based on the first-order shear deformation theory (FSDT), a closed-form solution is used to predict the out-of-plane core shear modulus and compared with ASTM procedure. Results reveal that including shear deformation effects, the determined shear modulus based on FSDT is larger than classical standard procedure. Furthermore, shear modulus of second-order corrugated core is smaller than first-order one of the same relative densities.