磁流变式调谐液柱阻尼器振动控制

首先综述了结构振动控制技术和调谐液柱阻尼器研究现状,指出了TLCD半主动控制研究存在的问题。结合磁流变(MR)阻尼器具有结构简单、阻尼力连续逆顺可调范围大、响应快等优点,以及调谐液柱阻尼器(TLCD)具有构造简单、使用经济的优良特性,研制了具有半主动控制性能的磁流变式调谐液柱阻尼器(MR-TLCD)。依据Langrage方程,建立了MR-TLCD.结构—MR-TLCD系统和桥梁—MR-TLCD系统动力方程,仿真分析了MR-TLCD的减振性能,并通过单自由度结构—MR-TLCD系统的被动、半主动控制试验,进一步评估了MR-TLCD的振动控制效果。主要研究内容包括：(1)研制了适合试验和工程应用的旋转剪切式MR阻尼器,根据旋转剪切式MR阻尼器力学性能试验,提出了MR阻尼力中的库仑摩擦阻尼力峰值与输入电流的玻尔兹曼函数关系,并证明了基于玻尔兹曼函数的Bingham模型是合理的。进一步准确描述MR阻尼器力学特点,克服Bingham模型在零速度附近不能说明阻尼力与速度的关系,采用了增加惯性力项的改进滞回力学模型,并由智能粒子群算法辨识了该模型参数。(2)研制了MR-TLCD减振装置,经MR-TLCD受简谐荷载时的七种输入电流试验分析,建立了带有阻尼比修正系数的MR-TLCD动力方程。通过试验与理论分析的MR-TLCD动力放大系数对比,拟合了阻尼比修正系数与输入电流之间的函数关系。与半主动控制试验对比,说明了采用阻尼比修正系数的MR-TLCD动力模型是正确的。(3)依据Lagrange方程,基于MR-TLCD力学模型,建立了试验／工程应用的单／多自由度结构—MR-TLCD系统的动力方程。提出了结构—MR-TLCD系统减振时域及频域分析方法,仿真分析了结构—MR-TLCD系统受随机风荷载作用时的被动控制减振效果结果表明：结构峰值及均方根值减振效果,随MR-TLCD输入电流大小和质量比而变化,且结构加速度控制效果优于位移控制。(4)拓展MR-TLCD减振装置应用领域,分析了MR-TLCD抑制桥梁风振被动控制效果。简谐荷载和随机风荷载仿真分析得到：四种截面类型的MR-TLCD都存在一个最小平均动力放大系数比及相对应的最优电流值；扭转峰值和均方根的角加速度控制都优于角位移减振效果。(5)基于单自由度结构—MR-TLCD系统动力方程,从MR-TLCD耗能受力角度分析,详细阐述了MR阻尼力和TLCD恢复力耗能情况,提出了基于耗能力的简单双态和两级双态半主动控制算法。半主动控制数值仿真分析表明,这两种控制算法减振效果显著,且采用两级双态控制算法时,整个系统更趋于稳定。(6)试验验证了MR-TLCD半主动控制的减振效果。制作了单自由度结构—MR-TLCD系统的半主动控制试验装置。利用dSPACE实时控制系统,实现了简谐、三阶谐波激励荷载下的被动控制关/开和简单双态、两级双态、离复位三种半主动控制算法。对结构峰值和均方根响应及减振百分比分析,进一步评价了MR-TLCD减振性能。
逆变焊机
Structural vibration control technology and the state of art of tuned liquid column damper (TLCD) were critically reviewed. The problems of classical semi-active TLCD were identified. Some excellent properties of MR dampers, such as simple construction, larger continuously adjustable damping force as well as fast response time, and characteristics of TLCD, such as economics, simple figuration, were combined to develop Magnetorheological tuned liquid column damper (MR-TLCD) that can accomplish semi-active control. Equations of motion of a building and a bridge structure incorporated with MR-TLCD were formulated by Lagrange equation. The control performances of MR-TLCD were simulated in the case of wind-induced response. Further, enhanced vibration control performances of MR-TLCD were demonstrated by experimental investigations of both passive and semi-active control scheme of the coupled SDOF—MR-TLCD. The main contents were summarized as follows:(1) Rotary Shear MR damper (RSMRD) was developed to meet the requirement of testing and engineering applications. The Boltzmann function formulation of relationship between the peak of coulomb friction damping force of MR damper and its input current was investigated based on mechanical properties test results of MR damper. It was proved that Bingham model based on Boltzmann function was reasonable. The mechanical characters of the MR damper were further described to solve the problem that Bingham model fails to capture the hysteretic curve of MR damping force and velocity around zero velocity, and the hysteretic model of RSMRD was calibrated with an improved hysteretic model with an additional inertial force item, where each parameter was identified by intelligent particle swarm optimization.(2) The control device MR-TLCD was developed. MR-TLCD excited by harmonic load was tested under seven input currents, and the dynamical equation of MR-TLCD with damping ratio correction factor was derived. The relationship of damping ratio correction factor and input current was fitted by dynamic magnification factors of theoretical and experimental analysis. By comparing semi-active control test analysis, it was further demonstrated that dynamical model of MR-TLCD with damping ratio correction factor was feasible.(3) The equations of motion of the combined structure-MR-TLCD system for the test cases or practical MR-TLCD were established by Lagrange equation. The analysis methods in time domain and frequency domain were proposed. The passive control performance of the coupled structure—MR-TLCD system subjected to random wind load was simulated. The results showed that the damping effect on peak and root mean square of SDOF structure varied with input current of MR-TLCD and mass ratio, and the control performance of acceleration response was better than that of displacement.(4) The passive control performance of the bridge with MR-TLCD was analyzed to expand the application of the control device MR-TLCD. The displacement and acceleration response of the system subjected to harmonic and random wind load was simulated. It is concluded that there are the minimum mean dynamic magnification factor ratio as well as the optimal input current for each of the four section styles of MR-TLCD. The acceleration control performance of bridge torsional peak and root mean square is superior to the displacement.(5) From the point of energy dissipation force of MR-TLCD based on the dynamical equation of the coupled SDOF—MR-TLCD, the energy situation of MR damping force and TLCD liquid restoring force was detailed. The Simple Bi-State (SBS) semi-active control algorithm and Two-Stage Bi-State (TSBS) semi-active control algorithm were developed based on energy dissipation. It was demonstrated that both the SBS algorithm and the TSBS algorithm based on MR-TLCD device had good obvious performance of vibration control by theoretical simulation analysis and experimental data of semi-active control. When the TSBS algorithm is adopted, the control system is easier to be stabilized.(6) The semi-active control device of the coupled SDOF—MR-TLCD was manufactured to verify the semi-active vibration control performance of MR-TLCD and compared with theoretical simulation. The real-time control system dSPACE was employed in the test set-up to realize the controller algorithms, which included passive off/on and semi-active control algorithms such as; SBS, TSBS and off-and-toward-equilibrium. Response value and damping percentage of the structure peak and root mean square were analyzed, and the control performance of MR-TLCD was further evaluated.