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中文核心期刊

硬磁软材料输流管的屈曲不稳定性分析

BUCKLING INSTABILITY ANALYSIS OF HARD-MAGNETIC SOFT PIPES CONVEYING FLUID

  • 摘要: 输流管道广泛应用于海洋工程、航空航天、先进制造和生物医学等工程行业和前沿科技领域. 在内部流体作用下, 软材料输流管易丧失稳定性并出现较大位移. 因此, 如何预测其稳定性以及调控其力学行为显得至关重要. 基于Hamilton原理, 建立了磁调控下硬磁软材料输流管道的动力学理论模型, 推导了铰支-可滑动铰支边界条件下输流管道的控制方程. 在Galerkin方法离散的基础上, 对输流管系统进行了稳定性分析. 研究发现: 当流速小于失稳临界值时, 输流管在静态平衡位置保持稳定; 当流速大于失稳临界值时, 输流管以静态分岔形式发生屈曲失稳. 通过求解输流管道的非线性控制方程, 得到管道的非线性力学响应. 研究结果显示, 磁场力幅值P和磁偏角α会共同影响输流管系统的非线性力学响应行为, α的取值决定了系统临界流速和管道屈曲形状随P值增大的演化趋势, 实现了对管道屈曲变形行为的磁调控. 理论模型还可方便地推广应用于非均匀磁化管道的力学响应分析之中. 文章采用的磁场调控方法具有非接触式和快速响应等优势, 可望进一步应用于医用器械及极端环境作业等领域.

     

    Abstract: Fluid-conveying pipes are widely used in marine engineering, aerospace, advanced manufacturing, biomedicine and other engineering industries and frontier science and technology. Under the action of the internal fluid flow, the soft pipe may lose stability and is easy to generate large displacement. Therefore, it is of importance to predict the pipe's stability and regulate its mechanical behavior. Based on Hamilton's principle, a theoretical model of hard-magnetic soft pipes under the actuation of the external magnetic field is proposed, the governing equation for a simply supported pipe with an axially sliding downstream end is derived. By employing the Galerkin method, the buckling instability of the pipe system is analyzed, and the magnetic regulation of the buckling deformation behavior of the pipe is realized. The calculated results show that when the flow velocity is below the critical value, the fluid-conveying pipe remains stable at the original straight configuration. When the flow velocity exceeds the critical value, the buckling instability occurs in the form of a static bifurcation. By solving the nonlinear governing equation of the pipe system, the nonlinear mechanical response of the pipe is obtained. It is shown that the magnetic field force magnitude P and the magnetic declination angle α together affect the nonlinear mechanical response of the pipe system. The value of α determines the evolution trend of the critical flow velocity and the pipe's deformed bending shape with the change of the value of P. The proposed theoretical model can be extended to investigate the mechanical response of non-uniformly magnetized soft pipes. The magnetic field regulation method adopted in this work has the advantages of non-contact and rapid response, and is expected to be further applied in the fields of medical devices and extreme environment operations.

     

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