时变磁场激励下金属圆板的电磁力特征分析  

Characteristic Analysis for Electromagnetic Force of Circnlar Metal plate under Time-Varying Magnetic Excitation

作　　者：蒋一萱 高原文[1] 周又和[1] 

机构地区：[1]兰州大学,兰州730000

出　　处：《应用力学学报》2006年第1期7-11,共5页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金青年基金(10302009);国家杰出青年基金;兰大首届交叉学科青年基金(Lzu200305)

摘　　要：电磁力的计算是电磁成形这一新型加工工艺的关键问题之一,目前在工程界多采用近似的磁压力公式pm=B2/2μ0。该公式对加工工件半径较大且外加磁场频率较高时较为适用,在外加磁场频率较低或工件半径较小时有较大误差。本文基于Maxwell方程组推导了在外加横向磁场作用下金属圆板上涡电流分布的特征,进而给出了电磁力解析表达式,在此基础上得到修正的电磁压力公式。分析结果表明:本文得到的修正磁压力公式在工件半径较大,外加磁场频率较高时和原磁压力公式趋于一致,对于小尺寸,外加磁场频率较低的情形也能进行模拟.这对低频磁场下,小尺寸工件的磁致成形工艺具有指导意义。Evaluation of electromagnetic force is essential in electromagnetic forming,a new style of processing technique.Based on Maxwell equations,a theoretical derivation is presented instead of the existing formula P_m=B^2/2μ_0 for the distribution characteristics of eddy current in a circular metal plate under the transverse magnetic exitation,and the analytic expression of electromagnetic force is deduced to modify magnetic pressure formula.The results indicate that modified magnetic pressure formula is coincident with the traditional one for the workpiece of larger radius in higher frequency magnetic fields,while the formula enables to simulate the situations of small-scale workpiece under lower frequncy magnetic exitations.

关 键 词：金属圆板 电磁成形 涡电流密度分布 等效磁压力 

分 类 号：O344.3[理学—固体力学]