圆弧浅拱面外动力稳定性实验研究  

Experimental Study on Out-of-Plane Dynamic Stability of Circular Shallow Arch

作　　者：李康杰[1] 刘爱荣[1] 卢汉文[1] 禹奇才[1] 

机构地区：[1]广州大学-淡江大学工程结构灾害与控制联合研究中心,广东广州510006

出　　处：《中山大学学报（自然科学版）》2015年第3期30-35,共6页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家自然科学基金资助项目(11272095;51378133)

摘　　要：对称作用于拱结构的周期性荷载,一般来说,只引起拱面内的对称振动,然而在一定的条件下可能引起很大振幅的面内反对称振动以及面外对称振动,这是拱结构由于参数共振引起的动力失稳问题。本文针对圆弧浅拱平面外动力稳定问题,基于激振实验,利用APS系列激振器模拟拱顶单点简谐激励,采用B&K测振系统测定圆弧拱横向振动响应,测得结构自振模态与阻尼比,通过往返不断扫频方式获得动力不稳定域边界,并与理论结果进行了对比分析,探究了其在周期集中荷载作用下的动力侧倾失稳机理,研究结果表明:当外部激励荷载频率约为结构2倍自振频率时,结构出现激烈的横向参数共振,并且只有外激励幅值大于临界激发力时才会发生参数共振,而阻尼条件的存在影响着临界激发力的大小,外激励幅值越大,参数共振现象越容易发生,该文验证了圆弧浅拱面外动力不稳定域计算结果的准确性,研究成果为拱结构的动力稳定设计提供了一定的参考价值。The periodic load on the arch,in general,only causes the symmetric in-plane vibration of the arch. However,under certain conditions,it can cause in-plane anti-symmetric vibration and out-of-plane symmetric vibration with large amplitude,which is so-called the instability problem of an arch structure due to the parametric resonance. Aimed at studying the out-of-plane dynamic stability problem of circular shallow arch,the experimental work is conducted trying to explore mechanism of the out-of-plane dynamic instability under concentrated periodic load. By applying APS series vibrator,the single point harmonic excitation at vault was simulated. The BK modal testing system was used to gain the transverse vibration response of circular arch including its vibration mode shape and damping ratio. The boundaries of unstable domain were distinguished by way of constant frequency back-and-forth sweep. The experimental results were compared with those from theory analysis,and the results show that remarkable transverse parameter resonance of the structure appears when the frequency of external excitation is about twice of the structural frequencies. The parameter resonance occurs only when the external excitation amplitude is greater than the critical excitation force. Tthe existence of the damping affects the value of the critical excitation force. The greater is the excitation,the easier does the parameter resonance phenomenon occur.The experimental work reported verifies the accuracy of calculating the out-of-plane dynamic instability domain of the circular shallow arch,and presents that research has reference value for the design of dynamic stability of arch structure.

关 键 词：圆弧浅拱 周期性荷载 参数共振 面外动力稳定 激振实验 动力不稳定域 

分 类 号：TU317[建筑科学—结构工程]