面向磁流体增强的骨架结构微成型设计及回弹特性研究

为提高磁流体密封液膜的刚度和抗压力性能，设计一种应用于磁流体密封的翻边Z型增强骨架，该骨架由软磁金属薄板微成型冲压而成。对软磁金属电工纯铁和无取向硅钢进行单向拉伸试验，得到2种材料的应力应变曲线。利用幂硬化准则对Z型骨架成型回弹特性进行理论分析，确定影响回弹的主要因素为材料参数、厚度、弯曲半径、开孔宽度等。利用有限元软件对成型回弹过程进行仿真，应用因素水平分析，以残余应变和最大回弹量为指标，分析板胚厚度、弯曲半径、开孔宽度对回弹的影响。仿真结果表明：在研究的范围内通过增大板胚厚度、减小弯曲半径、减小翅片宽度能有效降低骨架回弹；当厚度为0.3 mm，弯曲半径0.3 mm，翅片尺寸为2 mm×1 mm时骨架成型回弹量最小,运用硅钢材料比纯铁具有更小的回弹量。研究结果对软磁金属的微成型冲压及磁流体密封复合材料设计提供了参考。

Micro-forming Design and Springback Research of Skeleton Structure Developed for Magnetic Fluid Reinforcement

To improve the rigidity and anti-pressure performance of the magnetic fluid seal film,a new flanged Z-shaped reinforced skeleton for magnetic fluid seal was developed,which was formed through micro-forming and stamping of soft magnetic metal sheet.The uniaxial tensile tests were carried out to obtain the stress-strain curves of both soft magnetic metal electrical pure iron and non-oriented silicon steel materials.Some key factors that influence springback,such as material properties,thickness,bending radius,width of opening,etc,were identified according to the Power Hardening Criterion.The forming springback process was analyzed using finite element software,the influence of sheet thickness,bending radius,and width of opening on springback was analyzed by applying factor level analysis and with residual strain and maximum springback as indicators.The results show that the springback of the skeleton can be effectively reduced by increasing the thickness of the sheet metal,reducing the bending radius,or reducing the fin width.The springback of skeleton forming is found to be the smallest under the conditions including a thickness of 0.3 mm,a bending radius of 0.3 mm,and a fin size of 2 mm×1 mm.The silicon steel material has less springback than the pure iron.This work provides a reference for the micro-forming stamping of soft magnetic metal and the design of magnetic fluid sealing composite material.