Analysis of sheared edge quality in rotary blanking process based on Lemaitre damage model
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摘要: 為了準確表征材料變形中逐漸劣化的過程,引入考慮損傷與裂紋萌發的彈塑性本構模型.基于Abaqus/Explicit的二次開發接口,編寫耦合Lemaitre損傷模型的用戶子程序,根據算例驗證其可靠性.通過反復加載-卸載拉伸試驗并利用彈性模量變化法來獲得損傷參數值.建立輥式沖裁工藝有限元模型,應用Lemaitre損傷模型來預測斷面質量,并進行試驗驗證.分析沖裁間隙、模具磨損與板厚等工藝參數對斷面質量、沖裁力及扭矩的影響.結果表明:前刃口斷面質量總體上要好于后刃口,但光亮帶具有一定的傾角;塌角區會隨沖裁間隙增加而增大;模具磨損程度增加會導致毛刺急劇增大;最大沖裁力與扭矩會隨著板厚的增大而增大.
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關鍵詞:
- 沖裁工藝 /
- 斷面質量 /
- Lemaitre損傷模型 /
- VUMAT /
- 模具磨損
Abstract: To accurately describe the material degradation process from elastoplastic deformation to final rupture, an elastoplastic constitutive model was established to feature damage and crack initiation. A user-defined material subroutine VUMAT was developed, based on the Abaqus/Explicit platform, and its reliability was validated with an example. The damage parameter values were determined in cyclic loading-unloading tensile tests, using the Young's modulus weakening method. To predict the sheared edge quality, a finite element model of rotary blanking coupling with a Lemaitre damage model was built and the numerical results were compared with experimental results. The influences of blanking clearance, die wear and sheet metal thickness on the sheared edge quality, blanking force and torque were investigated. The results show that the sheared edge quality of the leading cutting edge is generally better than that of the trailing cutting edge, but the burnish depth of the leading cutting edge tilts at an angle. The rollover is larger, as is the die clearance. There is an extreme increase in the burr height when the degree of die wear is higher. The highest blanking force and torque values increase as the sheet metal thickness increases.-
Key words:
- blanking process /
- sheared edge quality /
- lemaitre damage model /
- VUMAT /
- die wear
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參考文獻
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