Microstructure evolution based particle chain model for shear yield stress of magnetorheological fluids

Abstract

To predict the shear stress of magnetorheological fluids (MRFs) under magnetic field and shear flows, a meso-microscale shear model is proposed based on the entire course of particle aggregates and chains. For this purpose, a systematic study on the microstructure evolution and rheological properties of MRFs is conducted by using molecular dynamics simulations. An efficient chain identification technique is introduced to count the number of particle chains within the suspension system. From the perspective of particle-level simulations, the microstructured behavior of MRFs involving particle aggregation and internal structure evolution of magnetorheological suspensions are addressed. Shear properties of MRFs derived by the proposed model are studied, and model verification by comparison with previous experimental data and predictions of the existing structural viscosity model is included as well. It is revealed that the proposed meso-microscale shear model exhibits satisfactory accuracy and efficiency for describing the rheological properties of MRFs. Besides, the critical factors linked with rheological properties of MRFs such as magnetic field strength, particle volume fraction and shear rate, are analyzed, further demonstrating the applicability of the proposed model in design and optimization of MRFs.

Progress in the study of electrorheological polishing: A review

“…The prediction results are verified by experiments. Peng and Pei (2021) systematically studied the microstructure evolution and rheological properties of MRF using molecular dynamics simulation. The microstructure behavior of magnetorheological suspension, including particle aggregation and internal structure evolution, is discussed from the perspective of particle scale simulation.…”

Development and Implementation of Energy-Efficient Magnetorheological Fluid Bypass Damper for Prosthetics Limbs Using a Fuzzy-Logic Controller

“…Other studies have focused on exploring the parameters that affect the characteristics of the MRF. These studies have investigated the microscopic characteristics of MRF in magnetic fields [48][49]. For example, Wang et al [50] studied the microscopic characteristics of MRF suspensions and deduced that the particle chain length of the MRF with a high particle volume fraction increases sharply with magnetic fields.…”

“…One of the challenges found in MRF dampers is the fluid particle separation which occurs when the particles radially separate perpendicular to the direction of the compressive force in the squeeze mode. Ismail et al [48] studied fluid behaviour when subjected to compressive forces. They concluded that fluid separates from the particle phase, changing the particle chain structure and causing pressure build-up due to increased resistance to compressive force.…”

Magnetorheological damper modeling based on a refined constitutive model for MR fluids

“…In our previous studies, the particle-level simulation method based on molecular dynamics modeling has been successfully employed to investigate the microstructured behavior and rheological properties of MR suspensions under different flow conditions (Pei and Peng, 2021; Peng and Pei, 2021). Here, some critical procedures and key points of the particle-level simulation method are presented.…”

“…Here, some critical procedures and key points of the particle-level simulation method are presented. For more details, please refer to Pei and Peng (2021) and Peng and Pei (2021).…”