中文摘要：

采用Gourdin的电磁动力学方法对金属电磁膨胀环动态拉伸过程进行分析,探讨了电流截断方式、加载过程欧姆温升对实验数据处理的影响。结果表明：按自由膨胀假设的实验模型分析,短路电流截断方式会引入较大误差,断路方式符合较好;试样环感应电流产生的欧姆温升很大,材料本构参数拟合时应考虑温度历史的变化。考虑电磁加载过程试样环的温度和应变率不断变化,提出采用单个实验应力-应变曲线来拟合得到应变率敏感系数及热软化系数的方法,结果与给定的本构参数符合较好。研究为电磁膨胀环动态拉伸实验设计及数据分析提供参考。

英文摘要：

The Gourdin＇s electromagnetic dynamics method was used to discuss the influence of ways of current cut-off and temperature rise induced by Ohm heat during the high strain-rate metal ring expanding tests driven by electromagnetic force on experiment results and data processing modes. The results show that on the basis of hypothetical model of free expansion,the short circuit way can introduce greater error than that of broken circuit way; the temperature rise induced by Ohm heat is large,so the temperature change should be considered during data processing and fitting of constitutive parameters. Considering the change of temperature and strain rate during the loading processing,a new constitutive fitting method was proposed to obtain the strain-rate-sensitivity factors and thermal soften coefficient by single stress-strain curve tested by metal ring expanding test. And the constitutive parameters fitting by this method can match the given results. The research can provide reference for the design and process analysis of dynamic stretching test of electromagnetic expanding ring.