铁凝胶的力磁耦合细观力学模型的建立

STUDY ON THE MICROMECHANICAL MODEL OF FORCE-MAGNETIC COUPLING FOR FERROGEL MATERIALS

以羰基铁粉颗粒为增强相,与双组分室温硫化硅橡胶混炼的方法制备了铁凝胶试样。利用X射线衍射仪(XRD)、MTS1196材料试验机研究了铁凝胶材料的微观组织和宏观力学性能。基于材料的微观结构特征和压缩性能实验数据,并考虑磁性颗粒相互作用能的影响,建立了铁凝胶材料的力磁耦合模型,从理论上分析了磁性颗粒的粒径、含量等对铁凝胶材料的磁致效应和宏观力学行为的影响。结果表明,压缩应变较小时其对材料的磁致压缩模量的影响不大。在较大的压缩应变作用下,磁致压缩模量随着不同磁场强度、磁性颗粒质量份数、粒径比的增加而增大。但磁性颗粒质量份数达到70 wt%以上时铁凝胶材料的延展性和断裂韧度明显降低。因此,制备铁凝胶时需对以上因素进行优化组合,以获得具有良好磁致效应的铁凝胶。该研究为铁凝胶材料的工艺制备和器件功能行为的优化提供了理论依据。

The ferrogel sample was prepared by carbonyl iron powder as conductive phase and vulcanized silicone rubber as matrix. The microstructure and mechanical properties of the sample are analyzed and tested by using X ray diffractometer （XRD） and MTS testing machine. Based on the analysis of the microstructure and morphology features and the compression performance data, a stress-magnetization coupled model was established in accordance with the magnetic interaction between particles, and some factors influencing on magneto-induced effect and macroscopic response of ferrogel are analyzed theoretically, including the magnetic particle content, size ratio, magnetic field strength and compress strain etc. The results show that the roughness has little effect on the average peak shear stress when compress strain is low, while with the increase of the normal stress, the magneto-induced effect comes into play. And the magneto-induced compressive modulus of ferrogel tends to increase with the increment of the magnetic particle content, size ratio, magnetic field strength and compression strain. If the mass fraction of the magnetic granular in ferrogel is more than 70wt% , the ductility and fracture toughness of ferrogel composites would be notably reduced. In order to gain ferrogel composites with excellent magneto-induced effect, the the optimized combination of the selected factors would be employed were in the preparation of ferrogel materials. This provides theoretical help for material production and optimization of functions and behaviors for the device.