An FFT-based method for estimating the in-plane elastic properties of honeycomb considering geometric imperfections at large elastic deformation

Abstract

The geometric imperfections in honeycomb cells inevitably arise during the manufacturing process and can affect the honeycomb’s mechanical performance. Hence, it is critical to identify and quantify the geometric imperfections and characterize the effects of these imperfections on the effective mechanical properties of honeycomb. In this study, the geometric imperfections inside the honeycomb were identified from micro-CT scan data. Using the obtained geometric topology, a Fast Fourier Transform (FFT) based method was employed in combination with the composite pixel method to predict the effective in-plane elastic properties of honeycomb at large elastic deformations. The results of the nonlinear homogenized prediction were compared with the experimental data and the prediction values from analytical models to investigate the effects of geometric imperfections. It was found that the predictions from the FFT-based method agreed well with the experimental results. However, the predictions from the analytical models significantly overestimated or underestimated the elastic properties, indicating that the geometric imperfections inside the honeycomb significantly influence its in-plane elastic properties.