磁场作用下轴向运动功能梯度Timoshenko梁的振动特性

The vibration characteristics of axially moving functionally graded Timoshenko beam under magnetic field

  • 摘要: 轴向运动结构的工程振动问题一直是动力学领域中的重要课题之一。为了更全面地分析工程中的振动,针对磁场作用下轴向运动功能梯度Timoshenko 梁的振动特性展开论述。基于梁的动力学方程组和相应的简支边界条件,应用复模态方法,得到不同参数时固有频率和衰减系数与轴向运动速度的对应关系。采用微分求积法分析磁场作用下前四阶固有频率和衰减系数随轴向运动速度的变化,并与复模态方法的结果进行对比验证。数据结果表明复模态方法得到的结果是精确解析解。衰减系数呈现不对称性,耦合固有频率呈现分离性。随着轴速、磁场强度和功能梯度指数的增大,梁的固有频率减小;随着支撑刚度参数的增大,梁的固有频率增大。

     

    Abstract: Engineering vibration of the axially moving structure always has been one of the important topics in the field of dynamics.In order to analyze the vibration in the project more completely,this paper discusses in detail the vibration characteristics of the axially moving functionally graded Timoshenko beam under magnetic field. The dynamic equations and corresponding simply supported boundary conditions of the axially moving functionally graded Timoshenko beam under the magnetic field are obtained. The complex modal method is used to obtain the corresponding relation between the natural frequencies and the attenuation coefficients and the axial speeds with different parameters. The differential quadrature method is used to analyze the variation of the first four order natural frequencies and attenuation coefficients with axial speed under the magnetic field. The results are compared with those of the complex mode method. The results show that the solution obtained by the complex modal method is an exact analytical solution.The attenuation coefficient is asymmetrical and the coupling natural frequency is separable. As the axial speed,the magnetic field strength,and functional gradient index increase,the natural frequency decreases. The natural frequency increases with the increase of the support stiffness parameter.

     

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