Experimental investigation of vibration modulation induced by spatially distributed internal nonlinearities in a parallel thin-beam system

Broadband vibration regulation is important for lightweight beam-like structures and vibration-sensitive detection systems under complex excitations. However, the mechanisms of spatially distributed internal nonlinear interactions in parallel thin-beam systems (PBSs) remain unclear, particularly from experimental evidence. Here, we introduce controllable spatially distributed internal nonlinearities (SDINs) into a PBS and establish a corresponding Lagrange-based model. Combined theoretical and experimental studies are performed to examine the effects of nonlinear parameters, installation position, and distribution number on vibration modulation. The results identify two distinct SDIN vibration states and show that effective nonlinear activation enables broadband vibration suppression. Spatial distribution further produces synergistic nonlinear interactions, allowing attenuation across multiple resonance regions. These findings verify the feasibility of spatially distributed internal nonlinear modulation and provide guidance for designing vibration-regulated thin-beam structures for beam-like supporting systems and vibration-sensitive detection equipment.