Flexural vibration of pipes is a common problem in many practical engineering applications, which usually influences the operating state of the system or even causes damage of the equipment. In the present work, an easy-realized design of phononic crystal pipe is proposed to implement vibration suppression by directly upgrading the bare pipe with attached sleeves without replacing the original structure. Based on the mechanism of Bragg scattering, flexural wave bandgap could be obtained with the periodical changing in cross section of the sleeved pipe. Sleeve installation generates both added mass and added stiffness simultaneously, which leads to the parabolic variations in edge frequencies of the bandgap against sleeve dimensions. Asynchronous recovery of the two frequency loci makes the bandgap close up when the sleeve covers about half length of the unit cell. This feature is not observed in analyses of binary phononic crystal pipes. Equivalent models are proposed to discuss the predicted variations, and the singular dependence of closure of bandgap on sleeve length is theoretical explained. Experiments are carried out to validate the feasibility of attaching sleeves for flexural vibration suppression of pipes. The proposed design could effectively attenuate the vibration energy with the intended bandgap.

管道弯曲振动是许多实际工程应用中普遍存在的问题，通常会影响系统的运行状态，甚至造成设备的损坏。在目前的工作中，提出了一种易于实现的声子晶体管设计，通过直接升级带有连接套管的裸管而不更换原始结构来实现振动抑制。基于布拉格散射的机理，可以得到随套管横截面周期性变化的弯曲波带隙。套筒安装同时产生增加的质量和增加的刚度，这导致带隙的边缘频率相对于套筒尺寸呈抛物线变化。当套筒覆盖晶胞的大约一半长度时，两个频率轨迹的异步恢复使得带隙闭合。在二元声子晶体管的分析中没有观察到此特征。提出了等效模型来讨论预测的变化，并从理论上解释了带隙闭合对套筒长度的奇异依赖性。通过实验验证了附加套筒抑制管道弯曲振动的可行性。所提出的设计可以有效地衰减具有预期带隙的振动能量。通过实验验证了附加套筒抑制管道弯曲振动的可行性。所提出的设计可以有效地衰减具有预期带隙的振动能量。通过实验验证了附加套筒抑制管道弯曲振动的可行性。所提出的设计可以有效地衰减具有预期带隙的振动能量。