管路的振动不仅造成噪声污染，而且造成机器设备的损坏。将声子晶体布拉格带隙原理引入到管壁的结构设计中，将管壁设计成沿轴向交替排列的周期复合结构，采用传递矩阵法，计算此周期弯管中轴向波及弯曲波的传输特性，同时用MSC有限元软件验证了传递矩阵法计算的正确性。研究表明平面周期管路存在弯曲振动、轴向振动带隙特性，在带隙频率范围内，对相应的振动波传播具有很强的衰减作用。进一步，研究材料阻尼比对管路振动特性的影响。

Longitudinal vibration and flexural vibration in a bend pipe system is studied. The bend pipe is modeled as a periodic composite materials structure based on the Bragg scattering mechanism of Phononic Crystals, and then obtain the Bragg band structure. Using a transfer matrix method, the frequency response functions (FRFs) of longitudinal vibration and flexural vibration are calculated to study the vibration transfer properties of the Bragg periodic L-shaped pipe. The correctness of the transfer matrix method is proved by the calculation of commercial software MSC.Patran. The effects of damping factor on the frequency response function of pipe vibration are considered. The periodic bend fluid pipe may be effective in vibration reduction in a complex pipe system.