基于构件模态应变能比的隔震烟风道结构等效线性化分析

Equivalent linear analysis of isolated gas duct based on the modal potential energy ratio

对大型烟风道采用热滑移型双凹摩擦摆(thermal sliding double concave friction pendulum system,TS-DCFP)隔震的结构等效线性化方法进行研究。推导了TS-DCFP采用滑移面等效半径、等效摩擦系数表达的三线性滞回模型的等效刚度和等效阻尼比,适于以非线性变形为主的摩擦摆隔震结构。建立了横向地震作用下的二自由度结构动力分析模型,基于构件模态应变能比,推导了振型组合阻尼比公式。采用提出的等效参数对二自由度烟风道隔震结构进行线性时程分析,并与三维模型非线性时程分析结果进行比较。分析表明,TS-DCFP用于烟风道隔震效果相当显著,且本文提出的等效线性化方法对道体反力、底部剪力的估计接近非线性时程分析结果,用于结构初步设计选型很有效。

An equivalent linear model for the seismic analysis of the isolated gas duct using thermal sliding double concave friction pendulum(TS-DCFP)system is established.The structure is modeled as a two-degree-of-freedom system in the transverse direction.Meanwhile,the effective stiffness and equivalent viscous damping ratio of an isolation bearing with tri-linear behavior are derived and the modal-combined damping ratio is obtained from the modal potential energy ratio of components.The model is verified by comparing the response of a linear time history analysis of the two-degree-of-freedom system with that from the 3D nonlinear time history analysis using the directly integrating method.