• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2020, Vol. 56 ›› Issue (18): 81-91.doi: 10.3901/JME.2020.18.081

• 材料科学与工程 • 上一篇    下一篇

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6061-T651铝合金动态力学性能及断裂准则修正

邓云飞, 张永, 曾宪智, 杨永刚   

  1. 中国民航大学航空工程学院 天津 300300
  • 收稿日期:2019-12-15 修回日期:2020-05-05 出版日期:2020-09-20 发布日期:2020-11-17
  • 作者简介:邓云飞,男,1982年出生,博士,副教授,硕士研究生导师。主要研究方向为材料与结构动态力学性能、冲击防护理论与应用。E-mail:yfdeng@cauc.edu.cn
  • 基金资助:
    国家自然科学青年基金(11702317)和中央高校基本科研业务费中国民航大学专项(3122019076)资助项目。

Dynamic Mechanical Properties and Modification of Fracture Criteria of 6061-T651 Aluminum Alloy

DENG Yunfei, ZHANG Yong, ZENG Xianzhi, YANG Yonggang   

  1. College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300300
  • Received:2019-12-15 Revised:2020-05-05 Online:2020-09-20 Published:2020-11-17

摘要: 为研究应力三轴度、Lode角、温度和应变率对6061-T651铝合金材料断裂特性的影响,利用万能材料试验机,分别进行不同应力状态、温度和应变率下的材料力学性能测试试验。首先,通过测试试验发现,6061-T651铝合金材料的断裂应变随应力三轴度的增加而减小,并且在低应力三轴度范围内,Lode角对材料断裂应变影响十分明显。当材料温度低于250℃时,温度对材料流动应力有显著影响,断裂应变基本不受温度影响;当材料温度高于250℃时,温度对材料的流动应力和断裂应变都具有显著影响。此外,应变率对6061-T651铝合金材料的断裂应变无显著影响。其次,基于力学性能试验结果,修正Johnson-Cook(J-C)断裂准则得到Modified Johnson-Cook(MJC)准则,标定MJC和Modified Mohr-Coulomb(MMC)断裂准则的各项参数。最后,采用一级气炮进行球形弹体撞击6061-T651铝合金板试验,得到靶板的弹道极限速度和失效模式。采用ABAQUS/Explicit有限元软件建立相应的弹体撞击靶板三维模型,进行数值模拟计算。通过对比试验与数值模拟结果,验证模型及其参数的有效性。相对于Lode角无关的MJC断裂准则,Lode角相关的MMC断裂准预测结果更接近于试验。

关键词: 应力状态, 断裂准则, Lode参数, 数值模拟, 应力三轴度

Abstract: In order to investigate the effects of stress triaxiality, Lode angle, temperature and strain rate on the fracture characteristics of 6061-T651 aluminum alloy materials, the mechanical property tests of materials are carried under different stress states, temperature and strain rate using universal material testing machine. Firstly, the mechanical property test results show that the fracture strain of 6061-T651 aluminum alloy material decreases with the increase of stress triaxiality. And also, the fracture strain of material related to the Lode angle parameter, especially the effect of the Lode angle more significantly at the range of lower stress triaxiality. When the temperature less than 250℃, the temperature of material has significant influence on its flow stress, while the influence of temperature on its fracture strain can be ignored. While the temperature more than 250℃, the temperature of material has greatly influence on its flow stress and fracture strain. Moreover, the strain rate has no significant effect on the fracture strain of 6061-T651 aluminum alloy. Subsequently, basing on the test results of mechanical properties, the Modified Johnson-Cook(MJC) criterion is obtained by modifying Johnson-Cook(J-C) fracture criterion, and the parameters of MJC and Modified Mohr-Coulomb(MMC) fracture criterion are calibrated. Finally, the impact test of sphere projectile penetrating the 6061-T651 aluminum alloy target plate is conducted on a one-stage gas gun, and also the ballistic limit velocity and failure mode of target are obtained. In order to verify the validity of the model and parameters, and the corresponding 3D model of projectile impact target is established by using ABAQUS/Explicit finite element software. The results showed that the prediction results of Lode angle dependent MMC fracture criterion is closer to th e test compared with the Lode angle independent MJC fracture criterion.

Key words: stress states, fracture criterion, Lode angle, numerical simulation, stress triaxiality

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