均質化法に基づく負のポアソン比を示す異方性積層セル構造体の有限要素解析

抄録

In this study, we propose an orthotropic laminated open-cell framework, which is constructed by lamination of inplane orthotropic microstructures made of elbowed beam and column members. We fabricate the structures by an additive manufacturing technique (3D printing) and demonstrate the uniaxial tensile tests. Results show that the fabricated structures exhibit high negative Poisson's ratio in the out-of-plane direction (parallel to the lamination direction) and maintain the high negative values up to the large elastic region. This elastic behavior with high negative Poisson's ratio is attributed to three-dimensional rigid rotation of the internal components. We next perform the finite element modeling using homogenization techniques in order to predict the elastic coefficients. In our simulations, we scope the two types of the cellular structures: one has the same geometry of a unit cell used in the experiments and the other is a different geometry where the bridging components located at the center are removed. The two cell units are termed as Cells A and B, respectively. The numerical results reveal that Cell A exhibits a high negative Poisson's ratio in the out-of-plane, which agrees well with the experiment, while Cell B exhibits near zero Poisson's ratios.