Key points are not available for this paper at this time.
Auxetic rotating polygons are instrumental for programmable design of metamaterials with tunable proprieties. Their particular configuration leads to a sudden but controlled transformation between different states. However, opposed to the conventional perspective of the static stability in the pre-buckling state, a dynamic buckling-type phenomenon is observed in experiments based on a finite rotating-polygonal network. Under harmonic excitations much lower than the static buckling limit, global longitudinal motions and local rotations contribute to the buckling-type deformation of the system. In this paper, we report this phenomenon and we develop an analytical discrete nonlinear model to understand this phenomenon. The discrete model parameters are rigorously identified and validated against finite element simulations, achieving good agreement in both static force–displacement responses and linearized modal analyses. Based on the analytical discrete model, the phenomenon is reproduced in dynamic simulations with nonlinear jump resonances on both ends of the rotation-excited branch where the global longitudinal mode is coupled with the local rotational mode. Our work not only unveils a previously overlooked dynamic instability mechanism in buckling-based materials, but also provides an analytical framework for predicting and designing auxetic rotating polygonal metamaterials, with implications for future applications in vibration control and soft robotics.
Yao et al. (Mon,) studied this question.