Chaotic metastructures for frequency self-conversion

In this paper, we propose a novel structural framework for chaotic metastructures that exhibit complex chaotic vibrations in a wide parameter space. This method is based on the design of the structure without the need for external adjustments. Moreover, we investigate the dynamic evolution process of chaotic metastructures and establish theoretical criteria for the occurrence of chaotic vibrations in these systems. Based on chaotic metastructures, we introduce a new concept for frequency control, which enables the transition from order to disorder and to a new order. Specifically, we design a frequency self-conversion device that automatically converts arbitrary input frequencies into a constant output frequency, irrespective of variations in the excitation frequency. This innovative frequency conversion mechanism fundamentally causes the system responses to not depend on excitation frequencies and structural dimensions. We anticipate that this approach will effectively address both low-frequency and broadband issues in vibration energy harvesting and expand the scope of nonlinear metastructures to the chaotic realm.