Flexural behavior of singly curved X-Cor® sandwich composite structures: Experiment and finite element modeling

The desire to produce more geometrically complex components from pin-reinforced X-Cor® sandwich composite structures requires that the effects of curvature on the flexural behavior be investigated experimentally and numerically. This will enable development of validated design tools accounting for the effects of the load distributions associated with curved geometries on the efficacy of the pin reinforcement. Singly curved X-Cor® sandwich composite materials have been fabricated from pin reinforced foam core and composite facesheets. Flexural tests have been performed with curved X-Cor® sandwich composites of two different radii of curvature: 6″ and 12″. Modeling of the flexural response has been performed using Finite Element Analysis (FEA) to predict the stiffness, strength and failure initiation. The reinforced core has been homogenized to simplify the core model and to account for the effects of pin reinforcements in the foam using a micromechanical modeling approach. The numerical results obtained by FEA have been compared with experimental measurements. A new stress interaction criterion has been used to predict the strength of the curved sandwich composite under bending. It has been found that the predictions from the numerical simulations correlated with experimental measurements.