Mesoscale modeling and experimental analyses for pantographic cells: Effect of hinge deformation

In order to synthesize exotic metamaterials, it was proposed to use as elementary components of metamaterial microstructures so-called pantographic cells. The use of a mesomodel based on Euler–Bernoulli nonlinear beam theory is utilized for describing their behavior when their characteristic sizes are of the order of millimeters. With an in-house code, in which the connecting hinges were modeled as elastic extensional and torsional elements, simulations were performed and compared with experimental data. The comparison was carried out for compression and extension tests. It is proven, both numerically and experimentally, that the hinges undergo different deformation mechanisms. As a consequence, for compression and extension tests, the distribution and the total value of the strain energy vary significantly. The analysis is made possible in parts via Digital Image Correlation, which allows kinematic fields to be measured and the hypotheses employed for developing the proposed model to be probed experimentally.