磁流变硅脂泥的静态和动态力学性能研究

摘要

传统的剪切增稠材料虽然具有明显的速率敏感特性,但由于不能实现力学性能的定向可控,使其在实践中存在局限性.针对这一问题,开发了一种将铁磁性颗粒分散到具有剪切硬化性能的硅脂泥基体中制备成的新型磁流变材料--磁流变硅脂泥(MRSP),实现了对这类材料的定向控制.为了研究磁流变硅脂泥的磁流变和剪切硬化效应,在磁场环境下实验采用流变仪对材料包括蠕变、应力松弛在内的静态力学性能和包括流变性、剪切硬化在内的动态力学性能进行测试.研究结果表明,磁流变硅脂泥的蠕变和应力松弛现象受外部磁场的影响显著;流变性受磁场影响,剪切硬化效应与剪切频率相关;另外,磁流变硅脂泥的储能模量自动地随加载角频率增加而急剧增加,并可以通过外部磁场来增强.%Although the traditional shear thickening material has obvious rate-sensitive characteristics,but they can not achieve the directional control of the mechanical properties,so that there are limitations in practical applications.A novel magnetorheological material defined as magnetorheological silly putty(MRSP) was developed by dispersing soft magnetic particles into silly putty matrix with shear stiffening property to achieve the directional control of such materials.In order to study the magnetorheological effect and shear hardening effect,the static mechanical properties including creep and stress relaxation and dynamic rheological properties of MRSPs in the magnetic field environment were tested by rheometer.The experimental results indicate that the external magnetic field exerts significant influence on the creep and relaxation behaviors.The rheological properties are affected by magnetic field,and shear hardening is related to shear frequency.Moreover,the storage modulus of MRSPs increases sharply in response to the external stimuli of increasing angular frequency automatically and can be enhanced by external magnetic field.