Studies of An Innovative Nonlinear Actuator for the Semiactive Control of Dispersed Civil Structures

9703805 MASRI目前用来产生控制力的致动器一般不足以限制土木结构在强烈地震震动下的反应。迫切需要新一代执行器能够在可能引起结构显著非线性变形的强地面运动下充分发挥作用。本研究的目的是开发一种新型的半主动减震装置，用于控制离散土木结构的地震反应。该控制程序使用带有可调(自适应)运动限制止动块的非线性辅助质量阻尼器，这些辅助质量阻尼器位于整个结构的选定位置，通过扰乱有序的振幅积累过程，在结构的动力响应中注入最佳量的“混沌”。结构在每个半主动非线性执行器附近的振动程度决定了执行器的主动控制间隙大小和激活时间。通过使用控制能量来调整执行器的关键参数，而不是像传统的主动控制方法那样直接衰减结构的运动，实现给定水平的振动控制所消耗的总能量得到了显著的改善。还将进行一系列的分析和试验研究，通过安装几个创新的非线性致动器的桥梁模型，并受到地震振动器的多点地震激励。***

9703805 Masri Presently used actuators to generate control forces are generally inadequate for limiting the response of civil structures under strong earthquake shaking. There is a critical need for a new generation of actuators that have the capability of adequately performing under strong ground motion which may induce significant nonlinear deformations in structures. The objective of this research is to develop an innovative semi- active damping augmentation device for controlling the seismic response of dispersed civil structures. The control procedure uses nonlinear auxiliary mass dampers with adjustable (adaptive) motion-limiting stops, located at selected positions throughout the structure, to inject an optimum amount of "chaos" in the structures dynamic response by disorganizing the orderly process of amplitude buildup. The degree of the structure's oscillation in the vicinity of each semiactive nonlinear actuator determines the actuator's actively-controlled gap size and activation time. By using control energy to adjust the actuator's critical parameters instead of directly attenuating the motion of the structure (which conventional active control methods do), a significant improvement is achieved in the total amount of energy expended to accomplish a given level of vibration control. A sequence of analytical and experimental studies by means of a bridge model to be provided with several innovative nonlinear actuators and subjected to multiple-support earthquake excitation by seismic shakers will also be conducted. ***