磁流变液微结构的实验观测

Experimental observation the micro-structure of MRF

磁流变液(MRF)的力学性能与其微结构密切相关,而其微结构的形成与演化受多种因素的影响。研究了静磁场和剪切作用下磁流变液微结构的形成与演化。在静磁场作用下,分析了颗粒体积分数和磁感应强度对其微结构的影响;在剪切作用下,观测了微结构的动态演化过程。实验结果表明,在相同磁感应强度下,随着颗粒体积分数的增加,通链数目逐渐增多,孤立链减少,且由相互独立的单链转变为相互聚集的束链,在相同颗粒体积分数下,随着磁感应强度的增加,颗粒链的间距增大,链的聚合度明显提高;在剪切过程中,成功地捕捉到了磁流变液颗粒链从形成→拉伸→断裂→重组的动态演化过程,当该过程达到动态平衡时,为磁流变液提供了稳定的抵抗宏观剪切的能力。

The controllable mechanical properties of magnetorheological fluids （MRF）mainly depend on the mi-cro-structure inside the material.Many factors affect the micro-structure.The formation and evolution of the micro-structure was studied experimentally when the MRF was in a static magnetic field and suffering a shear. The effects of particle volume fraction and magnetic induction were considered.The results show that the num-ber of the chains increases with the increase of the particle volume fraction,but the distance between two chains decreases with the increase of the particle volume fraction when at the same magnetic induction,the micro-structure transformed from continuous chains to get together form a glomeroplasmatic structure;at the same volume fraction,the distance between two chains increase with the increase of the magnetic induction and the polymerization degree of the chain was improved remarkably.During a shear,the dynamic evolution process of the micro-structure was observed.