Unbonded fiber-reinforced elastomeric isolator (U-FREI) is an improved device for seismic mitigation of low-rise buildings. The horizontal force — displacement behavior of U-FREI is nonlinear due to rollover deformation and the horizontal stiffness is a function of both vertical load and horizontal displacement. In this paper, stability of a prototype U-FREI is studied based on the dynamic response utilizing finite element (FE) analysis. Furthermore, the horizontal response of the isolator is also evaluated under the design vertical load and increasing horizontal displacement up to [Formula: see text] [Formula: see text] is the total thickness of rubber layers) to observe the rollout instability.

中文翻译：

---

通过有限元分析预测原型未粘合纤维增强弹性体隔离器的稳定性

非粘合纤维增强弹性体隔振器 (U-FREI) 是一种改进的低层建筑抗震装置。由于侧翻变形，U-FREI 的水平力-位移行为是非线性的，水平刚度是垂直载荷和水平位移的函数。在本文中，基于利用有限元 (FE) 分析的动态响应研究了原型 U-FREI 的稳定性。此外，隔震器的水平响应也在设计垂直载荷和水平位移增加至[公式：见文本] [公式：见文本]是橡胶层的总厚度）下进行评估，以观察滚动不稳定性。