论文部分内容阅读
桥梁耦合颤振是介于单自由度颤振和经典平板耦合颤振之间的振动现象,因而对经典平板耦合颤振机理的研究对于桥梁气动耦合颤振机理的理解是非常有益的。通过对系统竖向和扭转耦合振动运动方程进行分析,将系统振动参数的频率和阻尼比隐式地表达成主梁断面颤振导数的函数形式,导出了二自由度耦合颤振分析方法。将该分析方法的结果与系统特征值分析方法的计算结果进行了比较,验证了该分析方法的可靠性和适用性,并对理想薄平板断面气动耦合颤振的机理进行了研究。分析结果表明,对于理想薄平板断面来说,耦合颤振导数项对系统振动参数中频率的影响均较小,系统扭转和竖向振动模态的气动阻尼比主要由直接颤振导数项和耦合颤振导数项A1*H3*构成,其它耦合颤振导数项对系统气动阻尼影响都不大。
Bridge coupling flutter is a phenomenon of vibration between the single-degree-of-freedom flutter and classical slab-coupled flutter. Therefore, the research on classical slab-coupled flutter mechanism is very beneficial to the understanding of the bridge aerodynamic fluttering mechanism. By analyzing the coupled vertical and torsional vibration equations of motion, the frequency and damping ratio of the system vibration parameters are expressed implicitly as a function of the flutter derivatives of the main girder section. Two degrees of freedom coupled flutter analysis method is derived. The results of the analytical method are compared with those of the eigenvalue analysis method to verify the reliability and applicability of the method. The mechanism of the aerodynamic coupling flutter of the ideal thin slab section is also studied. The analysis results show that the coupling dither derivative has little effect on the frequency of the system vibration parameters for the ideal thin plate section, and the aerodynamic damping ratio of the system torsional vibration and the vertical vibration mode mainly consists of the direct flutter derivative term and the coupling The flutter derivative term A1 * H3 *, and other coupling flutter derivatives have little effect on the aerodynamic damping of the system.