Large deformations induced in planar pantographic sheets by loads applied on fibers: Experimental validation of a discrete Lagrangian model

In [1] a novel metamaterial has been designed and studied, whose performances include an enhanced toughness in extension: one of the problems to be solved in the further development of the concept involves the study of its deformation induced by loads concentrated on fibers (fiber pull-out test). A continuum model seems particularly unfit for the description of this kind of phenomena. As a consequence, in order to design a campaign of experimental tests we resorted to numerical simulations based on a novel Lagrangian, finite dimensional model for pantographic sheets. The developed code has the robustness features necessary to supply reliable predictions also in presence of very large deformations and, indeed, produces very accurate predictions. The agreement between the presented three-elastic-parameters discrete Lagrangian model and the numerous experimental measurements performed is very accurate. Therefore we are confident that, once we will have improved the model to include damage onset, it will be possible to describe also the rupture and final failure of planar pantographic sheets.