AZ31镁合金超声辅助拉深成形的数值模拟

Numerical Simulation of Ultrasonic-assisted Deep Drawing of AZ31 Magnesium Alloy

针对AZ31镁合金常温成形易破裂、高温成形易氧化的缺点,通过对压边圈施加超声振动研究了冲压过程中超声频率、振幅对板材冲压厚度(STH)、减薄率(TR)和极限拉深深度的影响。运用ABAQUS有限元软件建立仿真模型,对比AZ31镁合金在常温且不加振动时的拉深深度以及对应的板材厚度和减薄率,然后在此基础上对压边圈施加超声简谐振动,讨论超声振动对板材冲压成形性能的影响。结果表明:在振动频率从20 kHz到40 kHz的增长过程中,板材最小厚度呈先缓慢减小再激增最后下降的变化,其中在36~37 kHz区间内,板材最小厚度最大、减薄率最小;而随着振动振幅的提高,板材最小厚度、极限拉深深度呈现单调递增的趋势,减薄率则逐步递减。

Aiming at the shortcomings of AZ31 magnesium alloy, such as easy cracking at room temperature forming and easy oxidation at high temperature forming, the effects of ultrasonic frequency and amplitude on the stamping thickness(STH), thinning rate(TR) and the ultimate drawing depth of the sheet during stamping process were studied by applying ultrasonic vibration to the blank holder. The simulation model was established using ABAQUS finite element software. The drawing depth and the corresponding sheet thickness and thinning rate of AZ31 magnesium alloy at room temperature without vibration were compared, and then the ultrasonic harmonic vibration was applied to the blank holder on this basis. The effect of ultrasonic vibration on the sheet metal stamping performance was discussed. The results show that with the increase of the vibration frequency from 20 kHz to 40 kHz, the sheet minimum thickness change decreases slowly first, then increases sharply, and finally decreases. In the range of 36-37 kHz, the sheet minimum thickness is the largest and the thinning rate is the smallest. With the increase of the vibration amplitude, the sheet minimum thickness and the ultimate drawing depth show a increasing trend, while the thinning rate gradually decreases.