Low frequency band gap for box girder attached IDVAs

Elastic metamaterial is a kind of periodic structures in which the locally resonators are periodically arranged. The most prominent dynamic characteristic of the metamaterials is that they possess the frequency pass bands and band gap. In the band gap, the elastic waves will attenuate significantly and this property is potentially used to control low frequency engineering vibration. Although many efforts have been made to lower the band gap frequency and broaden the band width, the host beams are usually imaginary Euler beam with rectangular section, not Timoshenko beam with box-section in engineering, in which the effects of rotary inertia and shear deformation shall be considered. Moreover, how to design the metamaterial beam with light-weight and low frequency band gap is still a big challenge because the conflict between the frequency band gap and mass of resonators. To address this issue, the inerter-based dynamic vibration absorbers (IDVAs) are adopted to realize the low frequency band gap due to its amplification mechanism. Band gap structure of Timoshenko beam with IDVAs has been developed based on the spectral element method and validated by the test and numerical experiments. And then, a simplify method to predict the starting frequency of band gap has been presented and the band width has been broadened by band gap merging mechanism. Finally, a computer based design method of metamaterial box girder with IDVAs has been presented and applied to control the vertical vibration of footbridge box girder.

Automated summary

This article investigates the band gap structure of elastic metamaterials, focusing on the design challenges of lightweight and low frequency band gaps. The use of inerter-based dynamic vibration absorbers is proposed to achieve low frequency band gaps.