Yield stress calculation of MR fluid based on particle linkage and node particle models

Abstract The yield stress used to describe the strength of the rheological effects is the most important mechanical property index for magnetorheological fluids. The macroscopic yield stress originates from the microscopic inter-particle electromagnetic force and particle arrangement, and most of the existing constitutive model is based on the single-chain model. However, the single chains become double chains or even multiple chains when the particle concentration or magnetic field strength increases. It is assumed in the existing research the particles arrange in single chains because the evolution mechanism from single chains to double chains or multiple chains cannot be obtained. This work connects two parallel particle chains by particle linkage that simplifies to a node particle, which keeps the two single chains parallel all the time during shear. Besides, the node particle contains more energy, giving the particle chains more energy and generating greater yield stress, which is consistent with the microstructure of magnetorheological fluid. Based on the model of node particle, the yield stress of magnetorheological fluid is calculated and compared with the experimental value. The results confirm that the yield stress model based on particle linkage and node particle can provide greater precision, of which the error is 30% less than the single-chain model.