Torsional Wave Propagation and Vibration Reducing of Phononic Crystal Pipe with Periodic Torsional Support

In this paper, torsional vibration band gap properties of fluid filled pipe were studied by using the transfer matrix method (TMM). Compared with the results carried by FEM software, the established torsional dynamic model and proposed method were verified. The effects of pipe wall`s material and parameters of support on the torsional vibration band gap properties were analyzed. Furthermore, the relationship between rotational dynamic responses and vibration band gaps were investigated. These attenuation regions of responses show good agreement with the frequency of Bragg band gaps. Lastly, we explained the locally resonant phononic crystals band gaps form mechanism from the point of mechanical impedance mismatch theory, results show that the peak frequency of impedance mismatch defines the begin of both LRs and Bragg band gaps. In essence, the locally resonant is the same as periodic support from the impedance theory. The results of this paper could give some valuable suggestions on the vibration control of pipeline system.