一种双简支―悬臂梁反共振隔振器设计分析与试验

Design analysis and experiment of double simply-supported cantilever beam-type anti-resonant vibration isolator

  • 摘要:
    目的 为探究三元件型反共振隔振器的实现形式,提出一种由一根悬臂端含质量块的双简支−悬臂梁与一根双支撑梁所组成的机械装置 (BAVI)。
    方法 首先,分析双简支−悬臂梁的动态特性,推导其阻抗方程;然后,根据驱动点阻抗函数综合其低阶模型是单惯容与单弹簧二元件的串联结构,并解析低阶模型的等效参数;最后,通过装置试件设计与试验,验证其反共振特性和理论方法有效性,并在此基础上分析装置刚度特性及不同阻尼形式的效果。
    结果 结果表明,当跨度比 l \leqslant 1 \mathord\left/ \vphantom 1 6 \right. 6 时,装置的动力学模型符合三元件型反共振隔振器结构,具有“高静低动”刚度特性;在双简支−悬臂梁上采取阻尼措施后,可实现隔振区传递率以最大速率衰减的同时抑制共振峰的效果。
    结论 所提机械装置证明了三元件型反共振隔振器的可实现性,提供了一种简易可行的工程结构。

     

    Abstract:
    Objective To explore the implementation of a three-element-type anti-resonant vibration isolator, a mechanical device is proposed which is composed of a double simply-supported cantilever beam connecting to a mass block at the cantilever end and a double supported beam, i.e., beam-type anti-resonant vibration isolator (BAVI) .
    Mehtods  First, the dynamic characteristics of the double simply-supported cantilever beam are analyzed and the impedance equation deduced. Based on the driving point impedance function, a low-order dynamic model of the double simply-supported cantilever beam is synthesized, which is a series model consisting of a single inertial volume and a single spring. The analytical solution of the equivalent parameters for the low-order dynamic model is also obtained. The isolator prototype is then made and the test is conducted. The experimental results validate the anti-resonant characteristics of the isolator device, and the effectiveness of the theoretical analysis is also verified. Furthermore, research on the stiffness characteristics and effects of different types of damping is carried out.
    Results  The dynamic model of the isolator device accords with the three-element-type model when the span ratio is less than 1/6, and the isolator device has high static stiffness and low dynamic stiffness. By implementing one damping measure on the double simply-supported cantilever beam, the resonance can be absorbed while the transmissibility in the isolation frequency region attenuates at the maximum rate.
    Conclusion The results of this study prove the realizability of the three-element-type anti-resonant vibration isolator, and the proposed mechanical device provides a simple and feasible implementation in engineering.

     

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