旋转内接功能梯度材料梁刚柔热耦合动力学特性研究

RESEARCH ON DYNAMICS OF A RIGID-FLEXIBLE-THERMAL COUPLING ROTATING INTERNAL FUNCTIONALLY GRADED MATERIALS BEAM

  • 摘要: 对具有旋转内接功能梯度材料(functionally graded material,FGM) 梁系统的刚柔热耦合动力学特性进行研究。假定梁为Euler–Bernoulli 型,由双组分材料制成,其力学性能参数沿厚度方向呈幂律变化。考虑柔性梁的横向弯曲变形和轴向拉伸变形,并计入横向弯曲引起的纵向缩短,即非线性耦合项。采用假设模态法离散柔性梁的变形场,运用第二类 Lagrange 方程推导出系统的一次近似刚柔热耦合动力学方程,并编制旋转内接FGM梁动力学仿真软件。然后通过仿真算例详细研究了各种无量纲参数及温度变化对系统固有频率、临界转速以及动力学特性的影响。研究表明:内接FGM梁的径长比、功能梯度系数以及温度变化对系统的动力学特性均有较大影响。

     

    Abstract: The rigid-flexible-thermal coupling dynamics of a rotating internal FGM (functional gradient materials) beam system is studied. The beam is assumed to be of a Euler–Bernoulli type, made of two-component materials, and its mechanical properties change in a power law along the thickness direction. The transverse bending deformation and axial tensile deformation of the flexible beam are considered, and the longitudinal shortening caused by the transverse bending, namely the nonlinear coupling term, is taken into account. The deformation field of the flexible beam is discretized by the assumed mode method, and the first-order approximate rigid-flexible-thermal coupling dynamic equation of the system is derived by using the second kind of Lagrange equation, and the dynamic simulation software of the rotating internal FGM beam is compiled. Then the effects of various dimensionless parameters and temperature changes on the natural frequency, critical speed and dynamic characteristics of the system are studied in detail. The results show that the hub radius ratio, functional gradient coefficient and temperature change of the internal FGM beam have great influence on the dynamic characteristics of the system.

     

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