织构化冲压模具的应力数值模拟分析

Numerical Simulation Analysis of Stress in Textured Stamping Die

目的研究不同形状织构化模具在冲压后的应力大小和分布情况,从织构化模具应力集中角度,为改善模具寿命提供理论指导。方法利用SolidWorks建立冲压模具三维模型,并且在模具的凹模圆角区域设置三角形、圆形以及二者复合图形,来模拟模具表面的三角形微织构、圆形微织构和复合织构。利用HyperMesh进行网格划分,并在ABAQUS中对冲压过程进行仿真分析,研究表面微织构对冲压模具凹模应力的影响。结果加工织构的模具,在织构周围出现了应力集中,应力集中主要存在于模具表层很小的范围内,没有延伸至深处。当摩擦系数为0.1时,三角形和圆形复合织构化模具最大应力为1520MPa,相对于单一的三角形织构化模具,最大应力减小了3.5%,相对于圆形织构化模具,最大应力增加了13.6%。随着摩擦系数的增加,织构化模具在织构处的最大应力均表现出减小的趋势,而单一的三角形和圆形织构化模具在摩擦系数较大时,板料会发生断裂。织构化模具最大应力数值由大到小依次为:三角形织构化模具>三角形和圆形复合织构化模具>圆形织构化模具。结论表面织构化会造成模具在织构处的应力集中,而且不同形状的织构产生应力集中的程度不同。因此,考虑从改善摩擦学性能的角度提高冲压成形件的成形质量时,需要兼顾考虑模具因表面微织构而产生应力集中,影响其寿命的问题。

The work aims to study the stress magnitude and distribution of textured dies in different shapes after stamping, and then provide guidance for improving the life of the die from the perspective of stress concentration of the textured die. A three-dimensional model of stamping die was set in the SolidWorks, and the triangular micro-texture, circular micro-texture and composite micro-texture of the die surface were simulated by setting triangle, circle and composite pattern in the fillet area of the dies. The mesh of textured stamping die was divided by HyperMesh, and the stamping process was established in ABAQUS for numerical simulation. Finally, the effect of surface micro-texture on the stress of stamping die was studied. The stress concentration appeared around the texture of the textured die, but the stress concentration mainly existed in a small range of the surface layer of the die and did not extend to the inside of the die. When the coefficient of friction was 0.1, the maximum stress of the composite textured die was 1520 MPa. Compared to the single triangular textured die, the maximum stress was reduced by 3.5%. Compared to the circular textured die, the maximum stress was increased by 13.6%. With the increase of the friction coefficient, the maximum stress of the textured die at the texture showed a tendency of decrease. The blank of triangular texture die and circular texture die with larger friction coefficient would break during stamping. At the same time, the relationship of the maximum stress of different textured dies was: triangular textured die > triangular and circular composite textured die > circular textured die. Therefore, surface texturing causes stress concentration at the texture of the die, and the textures in different shapes induce a different degree of stress concentration. When the texture is introduced on the die surface to improve the forming quality of the formed part, it is necessary to consider the problem that the stress concentration of the die due to the surface micro-texture affects the life of the die.