New Magnetorheological Dampers And Its Intelligent Control Algorithms

Structural intelligent control system (SICS) is the advanced field of seismic engineering discipline, which do not have the potential to destabilize the structural system and require only a small amount of power, because those systems based on intelligent materials (e.g. MR damper) and semi-active control strategy, along with various of intelligent control algorithms. As the application of SICS has been deep gradually, various kinds of practicality problems are currently available. The focus of this dissertation is to develop a fundamental understanding of SICS based on MR dampers. Efforts are directed toward design, modeling, experimental verification and control algorithms. The research detailed is investigated from the following aspects:(1) Due to the demand of structural vibration, this dissertation first introduces MR technology through the discussion of MR fluid and by giving a broad overview of MR devices including a discussion of MR damper types, mathematical fundamentals, and an approach to magnetic circuit design. With the necessary background information covered, a finite element model was built to analyze and examine a 2-D axisymmetric MR damper and the optimization of circuit design is discussed.(2) Based on mechanical analysis on rheological characteristics of MR damper, a novel MR damper with helix slotted plunger is developed. Through performance experiment and comparison with theoretical analysis, the mechanical performance of MR dampers with various helix slotted plungers is investigated.(3) The rheology mechanism is discussed for the MR damper with helix slotted plunger. To describe the MR fluid field-dependent characteristics and helix-slot effects, the quasi-static model based on Bingham is developed.(4) A kind of multilevel assembly MR damper is developed based on finite element analysis of circuit design, in which the plunger is separated into various self-governed component accounting for the distribution of magnetic flux.(5) The practical hysteresis model is developed. Through neuro-fuzzy means, the intelligent inverse model of MR damper is discussed.(6) Through intelligent control theory, an improved control algorithm is proposed to predict damper force and eliminate the influence of time-delay. By means of off-line training and on-line modifying, an intelligent control system is acquired.(7) The dynamic characteristics of high-rise building are investigated by analytical research, then fuzzy-logic control strategy using MR dampers are developed. Theoretical analysis and numerical simulations show that the intelligent control system can efficiently reduce responses of high-rise building induced by earthquake.