Study on the Suppression of Free Vibration of Structures by Interconnection.

提出了通过连接构件将两个或三个结构互连来提高结构阻尼性能的步骤和算法。在驱动过程中，使用连接的两个结构的两自由度（2DOF）系统的运动方程和连接的三个结构的三自由度（3DOF）系统的运动方程来表示连接的框架结构的第一模态方程。提出了上述两自由度和三自由度系统中各连接单元的调谐方法，使两自由度和三自由度系统中各系统的阻尼性能达到均衡和最大化。然后，利用2自由度和3自由度系统连接单元的调谐方法，提出了互联框架结构连接单元的近似调谐方法，使互联框架结构的第一阶振型阻尼性能均衡和最大化。对二自由度和三自由度系统中元件的调谐方法进行了实验研究。通过阻尼自由振动试验，得到了模型框架的固有圆频率和模态阻尼比，并与理论值进行了比较。实验结果表明，所提出的调谐方法是有效的。对两塔和三塔、斜拉桥、兰格桥和简支梁桥的两根索、两层刚架结构进行了互连对阻尼性能的改善研究，并得到了证实。提出了采用一阶模态位移和二阶模态位移驱动两互联结构近似整定方法，提高整定方法精度的方法。提出了采用连接构件调谐方法的梁式动力吸收系统的调谐方法。

Procedure and algorithm of improving the structure damping performance were proposed by interconnecting two or three structures with connecting members. In driving the procedure, modal equations of the first mode of the framed structures interconnected were shown using the equations of motion of a two-degrees-of-freedom (2DOF) system for the two structures interconnected and the equations of motion of a three-degrees-of-freedom (3DOF) system for three structures interconnected. The tuning methods of connecting elements in the above 2DOF and 3DOF systems, by which the damping performance of each system in 2DOF and 3DOF systems was equalized and maximized, were proposed. And then the approximate tuning methods of the connecting members of interconnected framed structures, by which the damping performance of the first mode of the framed structures interconnected was equalized and maximized, were proposed using the tuning methods of the connecting elements in 2DOF and 3DOF systems.Experimental investigation for tuning method of elements in 2DOF and 3DOF systems was done. The natural circular frequencies and modal damping ratios of the model frames were obtained from experiment of damped free vibration and were compared with theoretical values. It became clear from experimental results that the proposed tuning methods are effective.Improvement of damping performance due to interconnection were investigated and confirmed for the following structures : Two and three towers, two cables of cable stayed bridges, Langer bridge and simply supported girder bridge, and two rigid framed structures with three stories.Improvement method of precision of the approximate tuning method of two structures interconnected was proposed by adopting the first and second modal displacements in driving the tuning method. The tuning method of beam-type dynamic absorbing system was also proposed by using the tuning method of a connecting member.