基于等效的夹层梁模型和伽辽金方法,首先推导了不可移铁磁简支梁式板的磁弹塑性动力控制方程,在此基础上采用龙格-库塔方法数值模拟了矩形、锯齿形、三角形和正弦形四类横向磁脉冲作用下,铁磁梁式板的动力响应曲线及其动力失稳特征。数值结果表明:在磁脉冲持续时间、磁脉冲峰值相同的情形下,铁磁梁式板发生动力失稳时,矩形磁脉冲对应的临界磁场值最小,依次为锯齿形磁脉冲,三角形磁脉冲,正弦形磁脉冲。数值结果还进一步展示了磁脉冲结束后,铁磁梁式板的残余构形等力学特征。
The magneto-elastic-plastic dynamic responses and the dynamic instability of a ferromagnetic beam-plate under some magnetic pulses have been studied in this paper. Based on the sandwich beam model for elastic-plastic analyses and Gerlerkin's Method, the magneto-elastic-plastic dynamic governing equations of the ferromagnetic beam-plate with unmovable simple supports are derived. Four types magnetic pulse with rectangular, triangular, sawtooth and sinusoidal shapes are taken into account and under which, some characteristic curves, such as dynamics response, dynamic instability and residual configuration of the ferromagnetic beam-plate are displayed in this paper. The numerical results indicate that the dynamic instability is strongly dependent on the amplitude, the shape and the duration of the pulse field. The critical magnetic field of pulse magnetic with rectangular shape is the smallest ; correspondingly, that for the case of sinusoidal shape is the largest.