中文摘要：

首先对利用磁致伸缩效应在钢绞线中产生纵向模态的方法进行了理论分析．利用Maxwell三维磁场有限元分析软件对99mm长，公称直径17．80mm的7芯钢铰线建立模型．并依照磁路设计的相关理论，设计了利用双磁路及三磁路为7芯钢绞线提供偏置磁场的方案．最后，通过对磁路中的每根钢丝表面及中截面磁感应强度的比较分析，证明三磁路比双磁路的磁场强度更大，均匀性更好．

英文摘要：

The method how to excite the longitudinal modes in the steel strands based on magnetostrictive effect is analyzed theoretically. The simulation model which is a seven-wire steel strand with 99mm long, 17.80mm nominal diameter is constructed by software Maxwell which is used for 3D electromagnetic field finite element analysis. According to corresponding theory of designing magnetic circuit, double magnetic circuits and three magnetic circuits are developed to provide bias magnetic for seven-wire steel strands. Magnetic circuit of surface and radial sections of steel strand is finite element analyzed. The results show that three magnetic circuits have not only stronger but also have better uniformity in magnetic field intensity.