门式框架结构平面外的动力失稳试验研究  

Experimental study for the out-of-plane dynamic instabilities of portal frame structures

作　　者：沈超[1] 张愿 李遇春[1] SHEN Chao;ZHANG Yuan;LI Yuchun(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《振动与冲击》2022年第20期151-157,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(51879191)。

摘　　要：针对(铰接式)门式框架结构平面外动力失稳问题进行了试验研究,采用新型的非接触式激振方法,进行了门式框架自参数内共振和非内共振的试验研究,观测和分析了门式框架结构平面外失稳的现象和机理,测量并探究了自参数共振的不稳定区域。结果表明:在门式框架的横梁上施加相当于柱自振频率两倍的周期性激励时,横梁的振动会作为参数激励引发柱在平面外发生主参数共振(动力失稳);若横梁自振频率约为柱自振频率二倍时,结构将发生平面外的自参数内共振;对比自参数内共振和非内共振不稳定区域,发现前者不稳定区域覆盖面积更大,说明自参数内共振更易触发,更具危害性。因此,在门式框架结构的工程设计中应关注自参数共振,尤其是自参数内共振的风险,避免其诱发结构平面外动力失稳。The out-of-plane dynamic instabilities of(hinged)portal frame structures are experimentally studied.A new non-contact excitation method was used to study the autoparametric internal resonance and autoparametric non-internal resonance of the portal frames.The phenomenon and mechanism of out-of-plane instability of portal frame structure were observed and analyzed,respectively.The unstable domains of autoparametric resonance were measured and investigated.Results show that when the frequency of periodic excitation applied to the horizontal beam is approximately equal to twice the natural frequency of the column,the vibration of the horizontal beam will be used as a parametric excitation to stimulate the out-of-plane principal parametric resonance(dynamic instability)of the column.If the natural frequency of the horizontal beam is about twice that of the column,the portal frame will occur out-of-plane autoparametric internal resonance.Comparing the unstable domains of autoparametric internal resonance and non-internal resonance,it is found that the unstable domains of the former covers a larger area,indicating that autoparametric internal resonance is easier to trigger and more harmful than the non-internal resonance.Therefore,more attention should be paid to the risk of autoparametric resonance,especially autoparametric internal resonance in the design of portal frame structures,so as to avoid the out-of-plane dynamic instability of the structure.

关 键 词：门式框架结构 平面外动力失稳 自参数共振 内共振 不稳定边界 

分 类 号：TV312[水利工程—水工结构工程] TV323