• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2023, Vol. 59 ›› Issue (4): 43-52.doi: 10.3901/JME.2023.04.043

• 材料科学与工程 • 上一篇    下一篇

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基于改进GTN损伤模型的镁合金镦粗成形损伤及裂纹预测研究

赵辰辰1,2, 刘江林1,2, 李子轩1,2, 王涛1,2   

  1. 1. 太原理工大学机械与运载工程学院 太原 030024;
    2. 太原理工大学先进金属复合材料成形技术与装备教育部工程研究中心 太原 030024
  • 收稿日期:2022-03-17 修回日期:2022-05-10 出版日期:2023-02-20 发布日期:2023-04-24
  • 通讯作者: 王涛(通信作者),男,1985年出生,博士,教授,博士研究生导师。主要研究方向为轧制工艺及设备、金属层状复合板轧制复合机理。E-mail:twang@tyut.edu.cn
  • 作者简介:赵辰辰,男,1998年出生。主要研究方向为材料损伤。E-mail:z14044681@163.com
  • 基金资助:
    国家自然科学基金重点(U1710254)、国家自然科学基金面上(52075359)、山西省基础研究计划(20210302124115)和中国博士后科学基金(2020M670710)资助项目。

Prediction of Damage and Cracking of Magnesium Alloy Upsetting and Forming Based on Improved GTN Damage Model

ZHAO Chenchen1,2, LIU Jianglin1,2, LI Zixuan1,2, WANG Tao1,2   

  1. 1. College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan 030024;
    2. Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024
  • Received:2022-03-17 Revised:2022-05-10 Online:2023-02-20 Published:2023-04-24

摘要: 镁合金在成形过程中极易产生开裂,精准的损伤预测可以为塑性成形工艺提供理论支撑。为此,基于含连续介质剪切损伤因子的Gurson-Tvergarrd-Needleman(GTN)损伤模型被应用于预测镁合金成形时的损伤演化,通过压缩试样的力-位移曲线标定了AZ31B镁合金的流动应力和剪切损伤参数,预测并验证了AZ31B镁合金在镦粗工艺下的表面损伤及开裂,扩展了模型对低应力三轴度下的成形工艺损伤预测的适用性。在此基础上,对AZ31B镁合金在受压条件下损伤成因、裂纹扩展进行了分析。结果表明,随着压缩位移的增加,镁合金侧面中心区域的切应力不断增加,在此作用下基体内部孔洞沿非垂直压缩方向伸长、聚合,最终形成宏观裂纹;镦粗后的试样侧面裂纹走向与垂直压缩方向所成角度范围为34°~46°,改进的GTN模型模拟结果为44°~54°,原始GTN模型模拟结果均呈90°;改进后的GTN模型可应用于预测镁合金在轧制、热冲压等工艺下的损伤演化行为,为后续工艺优化奠定基础。

关键词: AZ31B镁合金, GTN损伤模型, 镦粗成形, 低应力三轴度, 孔洞

Abstract: Magnesium alloys are highly susceptible to cracking during the forming process, and accurate damage prediction can provide technical support for the plastic forming process. To this end, the Gurson-Tvergarrd-Needleman (GTN) damage model with a continuous medium shear damage factor was applied to predict the damage evolution of magnesium alloys during forming, and the flow stress and shear damage parameters of AZ31B magnesium alloy were identified by force-displacement curve with compressed specimen to predict and verify the surface damage and cracking of AZ31B magnesium alloy under upsetting process. The applicability of the model for predicting damage in the forming process under low stress triaxiality was extended. On this basis, the causes of damage and crack propagation were analysed for AZ31B magnesium alloy under compression conditions. The results showed that with the increase of compression displacement, The shear stress in the center area of magnesium alloy side increased, under the effect of which the voids inside the matrix grew and coalesced in the non-vertical compression direction, and eventually formed macroscopic cracks; the lateral crack direction of the upset specimen was in the range of 34°-46° with respect to the vertical compression direction, and the simulation results of the improved GTN model were 44°-54°, while the simulation results of the original GTN model were 90°; The improved GTN model could be applied to predict the damage evolution behaviour of magnesium alloys under rolling, hot stamping and other processes, laying the foundation for subsequent process improvement.

Key words: AZ31B magnesium alloy, GTN damage model, upsetting forming, low stress triaxiality, voids

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