Bistable Nonlinear Tuned Cable-Inerter System for Superior Flapwise Vibration Control of Wind Turbine Blades

The mitigation of apwise vibrations is critical for the structural integrity and fatigue life of wind turbine blades. While passive absorbers like nonlinear energy sinks (NES) provide broadband attenuation, their need for internal blade mounting introduces practical challenges including concentrated local mass addition, potential interference with internal load-bearing members, limited geometric space for accommodating the required relative motion of the absorber components, and reduced accessibility for installation and maintenance. This paper introduces a novel, root-mounted Bistable Nonlinear Tuned Cable-Inerter System (BNTCIS) that overcomes these limitations. A comprehensive aeroelastic model of a rotating blade is developed via Hamilton’s principle, incorporating geometric nonlinearities, rotational effects, and gravitational loading. Realistic aerodynamic excitations are derived from TurbSim-generated wind fields and Blade Element Momentum theory. For the first time, a systematic comparison of eight absorber configurations-linear, cubic, pre-tensioned, and bi-stable variants of both NES and the newly proposed Nonlinear TCIS-is conducted. A multi-objective optimization framework (NSGA-II) simultaneously minimizes first and second modal responses and actuator stroke. Results conclusively demonstrate the supremacy of NTCIS over NES designs. The optimal BNTCIS configuration achieves a remarkable 93.47% reduction in the second-mode response and an 84.41% reduction in the first-mode response, while also demanding the lowest control stroke. Its root-based configuration avoids internal mass concentration, making it exceptionally suitable for implementation within the constrained geometry of turbine blades. This study establishes the BNTCIS as a superior and practical solution for passive vibration control in rotating structures.