基于传递与反馈特性的耦联结构的智能控制研究

Coupled structures refer to the structural systems that are composed of multiple subsystems with different dynamic properties and primary-secondary relationships. The economic loss and function failure of structures caused by earthquakes, in many sense could be attributed to the unfavorable internal mechanism of coupled structures..This project aims to study the deep mechanism of the seismic responses of coupled structures and achieve seismic mitigation objectives through introducing external disturbances, i.e., intelligent control means, to alter the system’s dynamic properties of state transfer and feedback. First, the law of the influence of main factors, such as location and structural parameters, on the seismic responses of serially and translation-torsionally coupled structures are studied, and the index of structural internal property - controllability, is used to explain and express the mechanism and simplify the coupling-related matrix calculations. Then, different intelligent control strategies, such as varying damping / stiffness control, LQG control synthesizing multiple support semi-active devices, etc., are to be applied on coupling problems of buildings and bridges. Through numerical analyses, the mechanisms by which these control strategies change the internal properties like the controllability, will be analyzed, the hidden physical meaning will be disclosed, and seismic mitigation effects will be compared. Then, an overall reliability of coupled structures that account for all sub-structures’ performances is proposed, and based on this, practical passive control methods will be studied through stochastic optimal control principles. Finally, structural experiments would be conducted to demonstrate the concepts and mechanism, validate the control effects, and compensate the insufficiency of theoretical studies.

耦联结构是指具有不同动力特性、存在主次关系的多个子结构组合而成的结构体系。地震造成的经济损失和结构功能的失效，很大程度上可归咎于耦联结构不利的内在机制。.本项目旨在研究耦联结构地震响应的深层机理，通过引进外部干扰，即智能控制手段，改变系统的传递和反馈特性，实现减震目标。首先，研究结构主要因素，如位置和结构参数等，对串联、平扭等不同耦联结构地震响应的影响规律，并探索用内部特性的指标-能控性，来解释和表达这种机理，简化耦联矩阵问题的算法。然后分别应用变阻尼/变刚度、LQG合并多点支撑半主动装置等控制方法，对建筑和桥梁的耦联问题进行控制研究，通过数值计算，分析各控制方法对系统能控性等特性的改变机制，揭示隐含的物理意义，比较减震效果。最后拟提出考虑耦联各部分结构性能的整体可靠度，研究基于随机最优控制原理的实用被动减震方法，然后通过实验，明确概念和机理、检验控制效果、补充理论研究不足。

本项目拟借鉴结构控制中的传递和反馈原理，基于能控性的概念构造系统输入与输出关系的指数，来衡量结构对结构性质变化和外界激励的敏感程度，从而了解结构固有的抗震性能并进行智能化的控制。计划中设立五类典型结构，进行数值分析和试验研究，但在实施中略作改动。主要内容有：1. 考虑多高层建筑的弯曲效应对结构变形的影响，通过弯曲-剪切耦合的集中质量模型分析弯曲刚度作用的机理，定量其进行TMD调谐与剪切结构的不同，并提出用能控性原理给出TMD调谐优化设计方法；2.先做了三个框架模型的TMD振动台试验，说明了结构刚度不同时，其地震破坏和TMD的调谐都有所不同，TMD对加强的及弱化的结构在地震前后的减震效果也有所不同；然后做了关于不同框架高宽比及隔振支座压应力的隔振效果的试验；3.研究了曲线桥的三个偏心源：半径带来的质心移动，支座布置带来的刚心错位，地震动输入角度带来的力矩改变，计算这三个因素下曲线桥的Grammian能控性、Hankel 奇异数，说明系统内在的能控性性质可以反映偏心带来的影响，因此这些指标可以用来指导曲线桥的设计；4.基于内容3设计了三组9个曲线桥的试验，验证能控性理论对偏心结构的有效性，并拟进一步做附加阻尼的减震和碰撞试验；5. 做了3个设防类别的框架结构的节点试验，得到了梁铰的非线性模型和能力易损性；6. 为设计隧道的加载试验架设计两种方案，拟通过研究衬砌和围岩的相互作用给出解决问题的理论路径；还研究了一些模块化装配式结构的短柱效应问题。目前没有完成智能控制的目标，拟在后续工作中进一步调整完善。