The Nonlinear Vibration Absorber for Mitigating Torsional Vibrations

From causing mild inconveniences to catastrophic failures, vibration affects all structural and mechanical components. The situation becomes especially critical when the structure is subjected to an exciting force that induces resonance. Industry trends towards lightweight construction compounds this issue by lowering the resonance frequency . The existing solution of attaching auxiliary linear vibration absorbers, is not so robust to changes in the structure, nor is it effective for mitigating other potential resonances. The Nonlinear Vibration Absorber (NVA) solves these issues by introducing nonlinear elements to the vibration absorber, offering a robust and broadly tuneable vibration control solution. Here, a piecewise-stiffening NVA is used to mitigate the torsional vibrations of a benchmark system. The piecewise-linear stiffness of the NVA mimics a cubic nonlinear stiffness, by the different angular engagement of flexural rods. The dynamics of the NVA-host system is studied analytically, by assuming the response to be of a single frequency; referred to as the first-order Complexification-Averaging scheme. The frequency response thus obtained has undesirable Isolated Resonance Curves and regions of quasi-periodic response, but shows 80%-87% reduction in the resonant response.