Numerical Investigation of Localized Mode Transitions in Nonlinear Oscillator Systems With Nonreciprocal Coupling Spring Under Impulsive Excitation

Intrinsic localized modes (ILMs) in nonlinear oscillatory systems offer promising applications in energy harvesting, vibration isolation, and noise control due to their asymmetric energy localization. However, their sensitivity to impulsive disturbances poses a challenge to practical implementation. This study investigates the role of nonreciprocal coupling in enhancing ILM robustness against impulse-induced transitions. A two-degree-of-freedom nonlinear oscillator system, coupled by a nonreciprocal spring, is modeled and analyzed numerically. The system is initialized in distinct ILM states and subjected to impulses of varying magnitudes and durations. The results reveal that the proposed system can stabilize ILMs by inducing controlled, unidirectional transitions within specific frequency bands, for impulse amplitudes up to a threshold of ten times the base excitation. Furthermore, the transition bandwidth is found to be tunable through the coupling stiffness. The findings in this study demonstrate that nonreciprocal coupling not only enhances ILM stability but also enables controllable dynamic responses under impulsive disturbances, offering strong potential for passive impact noise suppression and resilient vibration isolation in engineered systems.