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相互连接来改善结构减震性能的步骤和算法。在驱动过程中，利用两自由度(2DOF)系统的运动方程和三自由度(3DOF)系统的运动方程，给出了框架结构相互连接的第一振型的振型方程。提出了两自由度和三自由度系统连接元件的调整方法，使两自由度和三自由度系统的减振性能达到均衡和最大化。在此基础上，利用2自由度和3自由度体系中连接构件的调谐方法，提出了使连体结构第一振型的减振性能均衡和最大化的连杆结构构件的近似调谐方法，并对2自由度和3自由度系统中的构件调谐方法进行了试验研究。通过减振自由振动试验，得到了模型框架的固有圆周频率和振型阻尼比，并与理论值进行了比较。通过对两塔、三塔、两索斜拉桥、朗格大桥和简支梁桥以及两个三层刚架结构相互连接对减振性能的改善进行了研究和验证，提出了采用第一、二阶振型位移驱动两种结构相互连接近似调谐方法的精度改进方法。利用连接件的调谐方法，提出了梁式动力吸振系统的调谐方法。

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.