Analysis of a vibration isolation table comprising post-buckled Γ-shaped beam isolators
Analysis of a vibration isolation table comprising post-buckled Γ-shaped beam isolators
复制标题
包含后屈曲 Γ 形梁隔振器的隔振台分析
DOI：
10.1088/1742-6596/744/1/012224
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
T. Waters
中科院分区：
文献类型：
--
作者：
T. Sasaki;T. Waters
本文通过有限元分析研究了非线性被动隔振台的静动态特性。预期的应用特别是垂直方向的隔离，其中要求隔离器静态时足够硬以承受隔离物体的重量，而动态时要求足够软以承受围绕其平衡位置的小振动。建模配置由安装在两个 Г 形梁隔离器上的刚性隔离台组成，隔离器通过隔离质量的重量在不稳定屈曲模式下加载到屈曲后状态。提出了非线性静态分析来确定屈曲梁提供的负刚度，然后并联添加两个线性弹簧，选择具有足够的刚度来恢复稳定性。线性化系统关于其静态变形位置 (1mm) 的模态分析给出了仅为 1Hz 的固有频率，该频率远低于线性隔离器可实现的频率。当系统完全对称时，线性化系统的运动传递率显示出跨越二十年的非共振隔离区域，但当质量或刚度分布中包含不对称性时，会出现额外的共振峰值。人们探索了几种策略来减少这些共振的影响。
In this paper, the static and dynamic characteristics of a nonlinear passive vibration isolation table is investigated through finite element analysis. The intended application is specifically isolation in the vertical direction where the isolator is required to be sufficiently stiff statically to bear the weight of the isolated object and soft dynamically for small oscillations about its equilibrium position. The modelled configuration consists of a rigid isolation table mounted on two Γ-shaped beam isolators which are loaded to their post-buckled state in their unstable buckling mode by the weight of the isolated mass. A nonlinear static analysis is presented to establish the negative stiffness provided by the buckled beams, and two linear springs are then added in parallel which are chosen to have just sufficient stiffness to restore stability. Modal analysis of the linearized system about its statically deformed position (1mm) gives a natural frequency of just 1Hz which is considerably lower than is achievable by a linear isolator. Motion transmissibility of the linearized system shows a non-resonant isolation region spanning two decades when the system is perfectly symmetric but additional resonance peaks appear when asymmetries are included in either the mass or stiffness distribution. Several strategies are explored for reducing the prominence of these resonances.