延性金属渐进破坏试验与数值研究

Experimental and Numerical Study of Progressive Failure of Ductile Metals

金属构件韧性断裂机理研究对于新型延性材料缩短其工程应用周期及减少物理试验量等方面具有重要意义。基于连续损伤力学理论提出了一种改进的三应力不变量延性金属断裂模型,该模型考虑了静水压力和Lode角对损伤变量的影响。然后,以商业有限元分析软件ABAQUS为平台,通过编写用户材料子程序VUMAT的方式将该模型嵌入准静态算法主程序。通过对四种高强度变形铝合金2A12-T4板材的拉伸渐进破坏过程的试验及数值分析研究,验证了该模型的有效性。结果表明,该模型可很好地预测延性金属材料自裂纹萌生、扩展直至完全断裂的全过程。

The investigation of progressive failure of ductile metals is valuable for accelerating the application of ductile metals and reducing the physical experiments burden. In this paper, a modified three-stress-invariant ductile fracture model is proposed based on continuum damage mechanics, where the effects of hydrostatic pressure and Lode angle on damage variable are considered. To predict the progressive failure behavior of ductile metals, a series of experiments have been conducted for high strength aluminum 2A12-T4 sheets and the proposed model is implemented into quasi-static finite element method through a compilation of user＇s material subroutine VUMAT of the commercial finite element platform ABAQUS. The ductile fracture model is validated by comparing between experimental data and numerical results. It is shown that the proposed ductile fracture model can accurately and effectively predict the whole damage process of ductile metals including crack initiation, propagation and final fracture.