基于剪切修正GTN损伤模型的辊冲工艺数值模拟

Finite element simulation of rotary blanking based on a modified GTN damage model

  • 摘要: 在GTN模型基础上,考虑到微孔洞剪切变形对材料劣化的影响,建立适用于压应力状态的剪切修正模型.通过用户子程序接口VUMAT将与损伤耦合的弹塑性本构模型嵌入具有ALE法的有限元软件Abaqus/Explicit中.利用模拟拉伸与纯剪切试验拟合载荷-位移曲线以确定模型参数.将修正模型应用到辊冲工艺有限元模拟中预测断面质量,并进行试验验证.结果表明:前刃口为小间隙冲裁,塌角较小,光亮带较大但带有一定的倾角;后刃口为大间隙冲裁,塌角与断裂带较大,光亮带较小;裂纹会同时在前刃口凸模与凹模侧面萌发,而对于后刃口,会首先在凹模侧面产生.

     

    Abstract: Based on the GTN model,a modified GTN model applicable to compressive stress conditions was established by considering the effect of microvoid shear deformation on the loss of load-carrying capacity. The elastic-plastic constitutive model with the damage model was implemented in finite element software Abaqus/Explicit with ALE description through user subroutine VUMAT.Parameter values of the modified GTN model in simulation were determined by fitting the load-displacement curve in tensile and pure shear tests. Then,the modified GTN model was employed in finite element simulation of rotary blanking processes to predict the sheared edge quality and the simulation results were experimentally verified. The results show that for the leading cutting edge where the clearance is small,the roll-over depth is small and the burnish depth tilting at an angle is large. For the tailing cutting edge where the clearance is large,the roll-over and fracture depths are large and the burnish depth is small. Microcracks will simultaneously initiate near the flanks of the punch and die for the leading cutting edge,while for the tailing cutting edge they will occur firstly near the flank of the die.

     

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