Bending behavior and geometrical optimization of five-layered corrugated sandwich panels with equal in-plane principal stiffness

In this work, bending properties of five-layer sandwich panels with corrugated three-layer core are investigated both numerically and experimentally. Sheet metal forming is employed to construct the corrugated core and three-point bending tests are performed to experimentally evaluate the bending behavior of the panels. Besides, reliable finite element model is developed and validated by the experimental results. The results show that the phase difference of the external core has no considerable effect on the panel behavior. Next, the effect of orientation for the corrugated cores is studied for two 0/90/0 and 90/0/90 layups. The results show that bending rigidity of 90/0/90 is greater than other case due to more bending rigidity of the external cores. To design an optimum sandwich panel, genetic algorithm is utilized by constraining the mass and height of the panel. For optimization purpose, an analytical formulations that is validated by presented experimental and numerical results are used. Based on optimization results, optimized sandwich panel is constructed and exposed to TPB test. Good agreement is observed between all the numerical, analytical and experimental methods. The results indicate that the optimized configuration can achieve notable higher bending resistance in the same weight especially for the 90/0/90 case. Finally, an isotropic multilayered sandwich panel is introduced and optimized to overcome the drastic anisotropic properties of corrugated cores. The optimized isotropic panel have equal bending rigidity in two principal axes of the panel.