Designing Phononic Crystals with Wide and Robust Band Gaps

Abstract

Having a wide and robust phononic band gap is important for controlling mechanical waves in a real device that is imperfect or deformable. Band gaps due to Bragg scattering can be wide, but are intrinsically sensitive to imperfections and deformations, while those due to local resonances are robust, but typically narrow. By combining these two mechanisms (with the latter dominating), this study realizes simultaneously large and resilient band gaps, showing that suppression of instability is essential for robustness against deformation. This approach can drive applications such as devices for wave modulation, and thin-layer materials to control noise or vibration.