Strong internal resonance in a nonlinear, asymmetric microbeam resonator

• Published in: Microsystems & nanoengineering 2021-01, Vol.7 (1), p.9-9, Article 9
• Main Authors: Asadi, Keivan, Yeom, Junghoon, Cho, Hanna
• Format: Article
• Language: English
• Subjects: 639/166/987; 639/925/927/359; Asymmetric structures; Clamping; Coupling; Design parameters; Energy transfer; Engineering; Geometric nonlinearity; Intermodal; Microbeams; Nanoelectromechanical systems; Nonlinear systems; Parameter modification; Resonance; Resonators; Robustness; Signal detection
• ISSN: 2055-7434; 2096-1030; 2055-7434
• DOI: 10.1038/s41378-020-00230-1

Exploiting nonlinear characteristics in micro/nanosystems has been a subject of increasing interest in the last decade. Among others, vigorous intermodal coupling through internal resonance (IR) has drawn much attention because it can suggest new strategies to steer energy within a micro/nanomechanical resonator. However, a challenge in utilizing IR in practical applications is imposing the required frequency commensurability between vibrational modes of a nonlinear micro/nanoresonator. Here, we experimentally and analytically investigate the 1:2 and 2:1 IR in a clamped–clamped beam resonator to provide insights into the detailed mechanism of IR. It is demonstrated that the intermodal coupling between the second and third flexural modes in an asymmetric structure (e.g., nonprismatic beam) provides an optimal condition to easily implement a strong IR with high energy transfer to the internally resonated mode. In this case, the quadratic coupling between these flexural modes, originating from the stretching effect, is the dominant nonlinear mechanism over other types of geometric nonlinearity. The design strategies proposed in this paper can be integrated into a typical micro/nanoelectromechanical system (M/NEMS) via a simple modification of the geometric parameters of resonators, and thus, we expect this study to stimulate further research and boost paradigm-shifting applications exploring the various benefits of IR in micro/nanosystems. NEMS Resonators: Achieving strong internal resonance Achieving strong ‘internal resonance’ within a simple nanoelectromechanical resonator opens doors to further research and practical applications. Hanna Cho, and a team from The Ohio State University and Michigan State University, United States, describe in their new paper how internal resonance (IR) offers a “unique pathway” to steer vibrational energy, with applications in signal detection and simultaneous physical property sensing. Robust achievement of IR has proved challenging, with the property first realized in the early 2010s. The team now describe the robust generation of IR by a “relatively simple” nanoelectromechanical resonator, and the design parameters that can be manipulated to alter resonance behaviors. The team hope that their blueprints can act as a stepping stone for deeper investigation into the exploitation of IR for various applications.