Structural Hydraulic Passive Energy Dissipation And Direct Driving Active Control Systems

The research and application of structural control in civil engineering have made a great progress during the development of last several decades. A lot of innovative control devices are widely applied in actual projects. Up to now, passive control with simple structure and good performance, innovative active mass driver (AMD) system and time delay phenomenon that arises unavoidable regarding active control, are still the focus of study of structure control. In accordance with the above consideration, the main studies of this dissertation are as follows:1. Based on the equations of the route loss and local loss of fluid mechanics, the mechanical model of cylinder-with-holes damper using Newton fluid, exponent law fluid and Bingham fluid as damping medium. According to the theoretical results, four different dampers are designed and analyzed by mechanical experiment. By means of analysis of experimental data, the curve of damping force-velocity, damping force-damping medium, damping force-diameter of damping hole and damping medium-flow index are regressed, which is the key part for the design of damper and also important for the modeling, parameter specification and production of viscous fluid damper.2. Aimed at the disadvantages of traditional AMD drive device, such as large volume, high cost, complex system, more energy consumption, an innovative driver-Direct Driving Volume Control(DDVC) servo system for AMD is proposed based on the volume control of electro-hydraulic servo system. From the structure of DDVC servo system, the mathematical models of motor control, hydraulic power mechanism and hydraulic actuator of DDVC servo system are set up, which leads to the whole mathematical model of DDVC servo system. Through numerical simulation, the influence factor of system dynamics is analyzed in detail. Furthermore, the dynamical characteristic of each component of whole system as well as how to improve it is studied and proposed.3. Based on DDVC servo system, direct driving active mass driver (DAMD) is developed. The equation of rotation speed-drive force is derived and the corresponding rotation speed-force model using rotational speed of the pump (the driving voltage of servo motor) as input and the active control force as output is provided. From the above derivation and analysis, the state equation for controller structure-DAMD control system is presented. Numerical simulation is made on a structure under earthquake excitation with DAMD control system at the top floor. Results show that in some degree, DAMD control system can be used to substitute the traditional AMD control system to realized active control of structural vibration.4. Because the response time of DAMD control system is relative slow, the influence of this phenomenon under wind and earthquake excitation is analyzed. The stability analysis of time-delayed system is conducted and the analytical solution of maximum allowable delayed time of SDOF (Single Degree of Freedom) system is provided. This maximum allowable delayed time can be utilized to specify when to use the compensation for time delay. Meantime, the relationship between control gain and maximum allowable delayed time is presented. A direct compensation method based on mathematical analysis of time-delayed system is developed and corresponding numerical simulation verifies the effectiveness of proposed method.5. Almost all studies about how to control time-delayed system is to mitigate or remove the time delay. On the other hand, time delay can be regarded as the useful compensation for control system to a certain extent. In this dissertation, a novel compensation method for time-delayed system that directly utilizes time delay is developed. Based on the mathematical derivation, two methods using velocity feedback and displacement feedback are presented, respectively. Analysed and summarized the influence law between control effect and time delay control parameters by AMD control system. Furthermore, the effectiveness of the foregoing control methods that utilize time delay is verified by numeral simulation and experiment.