【作者】 程海斌；

【导师】 张清杰；

【作者基本信息】 武汉理工大学 ， 材料学， 2012， 博士

【摘要】 磁流变液是一种具有巨大应用前景的新型智能材料,磁流变液器件可以实现主动或半主动智能减振,解决常规方法无法完成的工程动力响应减振问题,但在重大工程中的实际应用仍然没有取得突破性进展。其中最重要的原因是：磁流变液的沉降,以及稳定性与流变性之间的矛盾,尚未得到很好的解决,至今仍然是挑战性难题。选择控制武汉天兴洲长江索拉桥主梁对列车刹车的振动响应,作为磁流变液阻尼器在重大工程中应用的突破口,系统研究了磁性粒子表面接枝表面改性剂,调控磁性粒子表面特性的方法,以及磁性粒子表面改性与纳米粒子协同调控磁流变液稳定性和流变特性的方法；研究了磁性粒子表面改性调控磁流变液稳定性的机理：增溶作用和增粘作用降低沉降速度、增容作用降低沉降率、Zeta电位的增大作用提高分散稳定性、屏蔽作用增强抗氧化性、润湿性提高改善再分散性；研究了磁性粒子体积分数和外加磁场强度与磁流变液屈服应力的关系,总结出2个调控磁流变液屈服应力的线性分析模型。制备出高稳定性、高屈服应力的磁流变液试样,通过了长期稳定性和流变特性检验,以及用其制造磁流变阻尼器的力学性能检验；然后,放大生产了500升高稳定性、高屈服应力和较低零场粘度的磁流变液,以及12个500kN磁流变阻尼器,安装在天兴州长江大桥的桥塔和桥面板之间,用于智能控制长江索拉桥主梁对列车刹车引起的纵向振动响应。模拟结果表明,采用半主动控制策略,由磁流变液阻尼器智能控制,可以在任何状况下确保桥面板纵向最大位移小于设计允许值30mm,最严重状况下的桥面板纵向最大位移下降87.0%,从149.2mm降低到19.4mm。最终实现了世界上第一个采用磁流变液阻尼器智能控制特大型桥梁振动响应的历史性突破。更多还原

【Abstract】 Magnetorheological (MR) fluids are one kind of new intelligent materials with great application prospects. MR intelligent devices can realize the initiative or semi-active intelligent damper, and solve some hard tasks, such as damping the dynamic responses of key engineering. However, there is still no significant practical breakthrough in key engineering application. One of the most critical bottlenecks is that sedimentation and settlement status evaluation of MR fluids, and the conflict between the stability and rheological property of MR fluids, still are challenging problems not yet solved very well.Aiming at the intelligent control of the longitudinal vibration response induced by train-braking on Wuhan Tianxingzhou Cable-stayed Bridge, and severing it as a breach, opening the range of application of MR fluids in key engineering. Researched and developed the methods of grafting surface modifier on the surface of magnetic particle, tuning the interface characteristics of magnetic particles, and collaboratively controlling the stability and rheology of MR fluids by surface modification of magnetic particles and nanoparticles; Analyzed the mechanism and principle of controlling the stability of MR fluids by surface modification of magnetic particles: solubilizing and viscosifying to reduce the settling velocity, and compatibilizing to reduce the sedimentation ratio, increasing Zeta potential to improve the dispersion stability, shielding effect to enhance the oxidation resistance, improving wettability to enhance redispersibility of MR fluids. Studied the relationship between the yield stress of MR fluids and their volume fraction of magnetic particles and the applied magnetic field intensity, and got two linear analysis models.The prepared MR fluid sample is proved to be high stability and high yield stress by passing through the long-term stability and rheological properties test, and the mechanics performance test of the MR damper prototype made with the home-made MR fluid sample; Then mass produced500L MR fluids with high stability, high yield stress and lower off-state viscosity, and produced12×500kN MR dampers with the home-made MR fluid, and installed them between the deck and lower cross beam at each tower of Tianxingzhou Yangtze river bridge for intelligent controlling the longitudinal vibration response induced by train-braking on Wuhan Tianxingzhou Yangtze river cable-stayed bridge. The simulation results show that the maximum of longitudinal displacement of deck will be sure smaller than30mm in all cases through semi-active control strategy by these12400kN MR dampers, even if in the most serious case, the maximum of longitudinal displacement of deck would fall from149.2mm down to19.4mm, reduced by87.0%. Finally, the world’s first breakthrough of intelligent control of vibration response of large bridge by MR dampers has become truth.更多还原