Shear rupture mechanism and dissipation phenomena in bias extension test of pantographic sheets: numerical modeling and experiments

In this paper, we show that a two-field model for pantographic sheets generalized to include a more refined description of the deformation of interconnecting pivots and structural dissipation, is capable of describing the sheets mechanical behavior for: i) cyclic extension tests in elastic regimes and ii) damage initiation. To this aim, we performed two kinds of experimental tests. In the first ones, we tested, remaining in the elastic regime, pantographic sheets under different cyclic loads. Secondly, we extended the specimens reaching the first rupture. The numerical model was calibrated in order to predict: i) the observed amplitude and shape of hysteretic cycles and ii) the observed localization of the first rupture. In this framework: i) a simultaneous rupture of several pivots is observed and theoretically justified, ii) the primary dissipation mechanism and rupture initiation are attributed to pivots’ shear deformation.