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Abstract Non‐Hermitian elastic systems featured with active components exhibit rich topological wave phenomena, including non‐reciprocal propagation, exceptional points, and non‐Hermitian skin effect. Despite these advances, the roles of elastic nonlinear and non‐reciprocal coupling on topological characteristics remains largely unexplored. In this work, the physical realization of a non‐Hermitian elastic metabeam with both nonlinear and non‐reciprocal coupling, realized by piezoelectric elements connected to programmable electronic circuits, is presented. An analytical framework is developed to describe amplitude‐dependent wave dispersion and winding numbers. The results show that Kerr nonlinearity enables tunable non‐reciprocity, twisted winding topology, and multiple non‐Hermitian topological phase transitions. Moreover, multi‐loop twisted windings arising from nonlinear and high‐order nonlocal effects are demonstrated and non‐Hermitian frequency conversion is validated both numerically and experimentally. This study opens new avenues for dynamic control of wave, offering a foundation for next‐generation elastic systems with amplitude‐responsive functionalities.
Qian et al. (Mon,) studied this question.