A sonic crystal angular rod with ability of multi-dimensional and broadband vibration reduction

Sonic crystal (SC) rod has apparent band gaps in which longitudinal or bending wave can be suppressed. However, the longitudinal wave band gap (LBG) and bending wave band gap (BBG) are located in different frequency ranges generally. Therefore, multi-dimensional vibration in the same frequency band can not be attenuated using single SC rod. For this reason, an SC angular rod is proposed consisting of two single SC rods. The in-plane and out-plane vibration are analyzed using transfer matrix method and finite element simulations are carried out. Our results show that: firstly, the attenuation of LBG and BBG can be fully utilized simultaneously in in-plane vibration owing to the transformation between longitudinal and bending waves and the SC angular rod has the ability of vibration reduction of 3-dimensions and 2-dimensions in BBG and LBG, respectively. Additionally, vibration of low frequency also can be isolated especially when loading angle is close to 90 degrees. Secondly, the performance of 90-degrees SC angular rod is superior to that of other angles such as 45 degrees and 135 degrees. Thirdly, loading angle has certain influence on the characteristics of in-plane vibration. When loading angle closes to 90 degrees the bending vibration becomes dominant and the attenuation in BBG gets stronger. At the same time the transfer peaks of bending wave lying in LBG also get strengthened impairing the attenuation in nearby frequency range. The contrary case is found when the loading angle closes to 0 degree.