扭力梁内高压成形的起皱行为

Analysis of wrinkling behavior of hydroformed torsion beam

摘要:

为了揭示扭力梁内高压成形时起皱的形成机制,采用实验和数值模拟的方法研究低碳钢扭力梁内高压成形过程支撑压力和补料量对起皱的影响规律;通过数值模拟给出起皱区应力状态,并绘制应力分布轨迹图,从应力分析角度揭示起皱形成机制．结果表明:随着支撑压力的提高,轴向压应力的绝对值下降,失稳起皱趋势降低,当支撑压力超过一个临界值时,皱纹完全消除;随着补料量的增大,轴向压应力的绝对值升高,失稳起皱趋势增大,当补料量超过一个临界值时,开始出现皱纹．对于直径为89 mm、壁厚为2.5 mm低碳钢管材,当支撑内压为30 MPa,补料量为15 mm,为一个合理的加载路径,可以有效避免起皱．

Abstract:

To obtain the mechanism of wrinkling behavior of hydroformed torsion beam, numerical simulation and experiments are carried out to analyze the effect of supporting pressure and axle feed on plastic wrinkling behavior during hydroforming process. Stress state and stress locus are gotten by numerical simulation, and they are used to analyze the reason of wrinkling behavior. The results show that the absolute value of axial compressive stress can be reduced by increasing the supporting pressure, and the wrinkling tendency declines. The absolute value of axial compressive stress can be raised by increasing the axle feed, and the wrinkling tendency increases. The wrinkles can appear while the supporting pressure reaches a critical value. To avoid wrinkling, the reasonable load path is that the supporting pressure is 30 MPa and the axle feed is 15 mm for a low carbon steel tube with an outer diameter of 89 mm and a wall thickness of 2.5 mm. 