非同轴质量偏心结构平扭耦合风振响应的研究

Wind-induced lateral-torsional coupled vibration responses of a structure with non-coaxial mass eccentricity

为了详细地对比分析结构各质量中心不在同一轴线上的偏心对结构风致平移-扭转耦合响应的影响,提出了分析非同轴质量偏心结构风振响应的基本框架。首先,建立了两层六自由度非同轴质量偏心结构的动力方程,并将其推广至N层3N自由度的非同轴质量偏心结构动力方程;然后,基于高频力平衡(HFFB)技术和多点同步扫描(MPSS)技术获得的顺风向、横风向以及扭转风荷载功率谱,考虑横风向和扭转风荷载之间的相关性以及模态之间的耦合,在频域内进行非同轴质量偏心结构的风致平移-扭转耦合响应分析。一栋120 m高的矩形钢结构建筑,被简化为15个自由度的三维分析模型作为数值研究案例。通过设置不同位置的结构质量偏心,分析研究了单轴质量偏心、非同轴质量偏心对矩形建筑结构平移-扭转风振的影响。

In order to comprehensively and comparatively investigate the wind-induced lateral-torsional responses of a structure whose mass centers at different floors were not located on a single vertical axis,a dynamic analytic framework for non-coaxial eccentric structures under wind loading was presented here.First,the dynamic equations of a N-storey non-coaxial eccentric building,with 3N-degree-of-freedom,was set up via expanding dynamic equations of a two-storey non-coaxial eccentric structure with 6-degree-of-freedom.Then,based on the power spectra of the wind forces in along-wind,across-wind,and torsional directions established with the high frequency force balance（HFFB） technique and the multiple point synchronous scanning（MPSS） technique,and simultaneously considering the structural mode-coupling and the statistical correlation between across-wind and torsional loading,the wind-induced lateral-torsional coupled responses of a structure with non-coaxial mass eccentricity were analyzed in frequency domain.According to the present framework,the effects of non-coaxial mass eccentricity on the wind-induced lateral-torsional coupled responses of a rectangular steel structure with height of 120m simplified as a three-dimensional analytical model with 15-degree-of-freedom were analyzed through setting different locations of mass eccentricity.