Enhanced bidirectional variable modulus property in NdFeB-based MREs via magnetocrystalline anisotropic and optimized particle distribution

Abstract To improve the wide-frequency vibration control capability of semi-active vibration isolators, the bidirectional variable modulus performance of hard magnetic magnetorheological elastomers (H-MRE) is crucial. To further enhance the characteristics of H-MRE, various technical solutions have been implemented in recent years, including filling H-MRE with pre-magnetized hard magnetic particles and doping soft magnetic particles into H-MRE. However, existing studies have faced issues such as particle agglomeration and complex preparation processes. In response to the contradiction between the complexity of the H-MRE preparation process and performance improvement in existing research, this study improves MRE performance by optimizing the hard magnetic particles and their distribution in H-MRE. By replacing traditional hard magnetic particles with magnetocrystalline anisotropic NdFeB particles, which exhibit better magnetic properties such as remanent magnetization, coercivity and saturation magnetization. The study systematically investigates the mechanism by which particle distribution influences H-MRE performance. Experimental results show that while enhancing the amplitude of positive modulus changes, the reverse modulus change amplitude of H-MRE is increased to 23.3%. This study lays an important foundation for the application of H-MRE in vibration control fields.