INVESTIGATIONS OF SUSPENSION BEHAVIORS OF MAGNETORHEOLOGICAL FLUID USING LARGE-SCALE MOLECULAR DYNAMICS SIMULATIONS

摘要

Magnetorheological fluid (MRF) dampers have been attracting increasing attention and are of growing importance in mitigating natural hazards,and enhancing the safety and serviceability of structural systems. As the critical component of this control device,MRF consists of magnetizable particles and nonmagnetic fluid,and its dynamic characteristics rely on the structural behaviors of suspensions. In the present paper,a large-scale atomic/molecular parallel simulator (LAMMPS) is employed to investigate the chain-like structures of MR suspensions,with mono-disperse and bi-disperse suspensions,respectively,under different magnitudes of magnetic fields towards numerically revealing the physical origin of MRF. It is indicated that the suspensions form chain-like sheets along with the magnetic field. The higher the magnetic field,the easier the suspensions form chain-like sheets,and the stronger the network built up by particles is supposed to be. In case of the presence of steady shear,the chain-like structures become frangible,which submit to the flow field,and connect to form long sheets along flow direction allowing for restraining the transportation of the shear flow.