基于有限元法的周期拱形结构振动特性

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设计一种新型低频隔振系统,该系统利用拱形的结构特点,将拱形结构重组设计后沿竖直方向周期化排列,形成周期拱形结构。运用有限元法结合Bloch定理对周期拱形结构的振动传播特性进行理论推导,并讨论尺寸和材料参数对振动带隙的影响规律。讨论发现,拱形高度对隔振频率范围没有影响,这能够很好解决工程实际中在某一方向有空间尺寸限制的问题,实现此方向小尺寸隔振的目的;隔振频率的降低可以通过增加结构长度、减小材料厚度、降低材料弹性模量和密度来实现。通过有限元分析软件和试验测试证实了周期拱形结构带隙算法的有效性。分析和测试结果证明,周期拱形结构具有小尺寸抑制该方向低频振动的能力,这对工程实际中的低频隔振技术具有参考价值。 A novel low frequency vibration isolator is established.The isolator is called periodic arch structure,which is composed of a number of identical reordered arch structures connected together along the vertical direction.The propagation characteristics of flexural waves in periodic arch structure are investigated by combining Bloch theorem with the finite element method,and the effect of dimension and material to band gaps are discussed.The discussions find that the height of the arch structure has no influence to the band gap,and the short height insulated low frequency vibration can be realized,which can solve the problem of dimension limit in practical application.The discussions also find that the range of band gap can be reduced by increasing the length of the structure,decreasing the thickness,modulus and density of the material.The predictions are validated by computation and experimental analysis of the harmonic responses of a finite structure with five unit cells.These studies provide guidelines to designing periodic structures for low frequency vibration attenuation.