Effect of stress triaxiality on fracture failure of 6061 aluminium alloy


  • L. Y. Kou School of Mechanical Engineering, Ningxia University, 750021 Yinchuan, Ningxia, China
  • W. Y. Zhao School of Mechanical Engineering, Ningxia University, 750021 Yinchuan, Ningxia, China
  • X. Y. Tuo School of Mechanical Engineering, Ningxia University, 750021 Yinchuan, Ningxia, China
  • G. Wang School of Mechanical Engineering, Ningxia University, 750021 Yinchuan, Ningxia, China
  • C. R. Sun State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, Hunan, China




6061 aluminium alloy, stress triaxiality, digital image correlation, Johnson-Cook failure model, fracture analysis


The effect of stress triaxiality on mechanical properties of 6061 aluminium alloy extruded profiles with different specimens was studied. Macroscopic mechanical property of the various specimen was got through universal testing machine. At the same time, stress triaxiality of different specimens was obtained using the method of finite element simulation. And then the fracture strain of each specimen was outputted by DIC. Fracture modes of 6061 aluminium alloy with different stress triaxiality were studied by SEM. The results show that taking tensile samples as comparison, the cross-sectional area of some notched specimens decreases and the peak load increases. Among them, the minimum cross-sectional area of the R5 central hole specimen is 20% smaller than that of the tensile sample, and the peak load is 28% larger. The fracture strain of the alloy increased with the decrease of stress triaxiality. For the same notch specimens, along the path direction, stress triaxiality of R5 notch specimens, R5 Center-hole specimens and R20 Arc notched specimens increased 47%, 17.8%, 25% respectively. According to the analysis of fracture morphology, the main fracture of 6061 aluminium alloy was ductile fracture. When the stress triaxiality is large, the dimples are small and sparsely distributed, and when the stress triaxiality is small, the dimple is large and evenly distributed. Finally, the Johnson-Cook model material parameters of 6061 aluminum alloy are fitted based on the tensile test results of different shapes of specimens, which can accurately simulate the elastic-plastic deformation and fracture instability of 6061 aluminum alloy under different stress states.


N. Le Maoût, S. Thuillier and P. Y. “Manach, Aluminum alloy damage evolution for different strain paths – Application to hemming process,” Eng. Fract. Mech., vol. 76, no. 9, pp. 1202–1214, 2009, doi: 10.1016/j.engfracmech.2009.01.018.

F. A. Mcclintock, “A criterion for ductile fracture by the growth of holes,” J. Appl. Mech., vol. 35, no. 2, pp. 363-371, 1968, doi: 10.1115/1.3601204.

J. R. Rice and D. M. “Racey, On the ductile enlargement of voids in trixial stress fields,” J. Mech. Phys. Solids., vol. 17, no. 3, pp. 201-217, 1969, doi: 10.1016/0022-5096(69)90033-7.

A. L. Gurson, “Continuum theory of ductile rupture by void nucleation and growth,” J. Eng. Mater. Technol., vol. 99, pp. 2-15, 1977, doi: 10.1115/1.3443401

Y. S. Lou and H. Huh, “Evaluation of ductile criteria in a general three-dimensional stress state considering the stress triaxiality and the lode parameter,” Acta Mech. Solida Sin., vol. 26, no. 6, pp. 642-658, 2013, doi: 10.1016/S0894-9166(14)60008-2.

Q. Song, Y. Huang and J. Zhang, “Simulation on tensile behavior of Q345 steel notched plate and revision of constitutive relation,” J. Guangxi Univ., vol. 4, pp. 1554-1561, 2018, doi: 10.13624/j.cnki.issn.1001-7445.2018.1554.

A. M. Tang and Z. M. Liu, “The Experiment Analysis for Fracture Laws of Aluminum Alloy Materials,” J. Xi’an Univ. Tech., 2003, vol. 3226-229.

H. Zhu, L. Zhu and J. H. Chen, “Study of mechanical performance and analysis of fracture surfaces of aluminum alloy in three patterns of stress state,” J. Lanzhou Univ. Tech., vol. 32, no. 6, pp. 28-31, 2006, doi: 10.1016/S1003-6326(06)60040-X.

H. Zhu, L. Zhu and J. H. Chen. “Fracture Mechanism on 6063 Aluminum Alloy under Different Stress States by in-Situ Tensile,” Rare Met. Mater. Eng., vol. 7, pp. 1183-1187, 2008, doi: 10.1016/j.precisioneng.2007.08.007.

M. Lu, J. Yang and F. F. Liao, “Fracture mechanism of Q460D structural steel under different stress state,” Heat Treat. Met., vol. 41, no. 7, pp.172-177, 2016, doi: 10.13251/j.issn.0254-6051.2016.07.041.

Y. J. Wu, X. C. Zhuang and Z. Zhao, “Fracture topography analysis of C45 steel under different stress state,” J. Plast. Eng., vol. 20, no. 3, pp. 106-110, 2013, doi: 10.3969/j.issn.1007-2012.2013.03.020

X. L. Jia, J. Wang and Y. L. Zhang, “Mechanical behavior of typical materials under full load under complex stress,” Chin. J. Appl. Fundam. Eng. Sci., vol. 2, pp. 202-213, 2017, doi: CNKI: SUN: YJGX.0.2017-02-018

D. Jia, X. C. Huang and J. Mo. “A method to determine stress triaxiality of notched specimens from tensile tests,” in China Conference on Computational Mechanics, 2012.

H. Y. Zhuang, Y. M. Tian and X. H. Lai. “Fracture test and fracture model establishment of sheet metal under different stress states,” Automob. Tech. Mater., 2016; 11: 43-47. 10.3969/j.issn.1003-8817.2016.11.014

S. J. Fan, G. Q, He and X. S. Liu, “Analysis of The Microstructure and Tensile Fractographs of A356 Alloy,” Met. Funct. Mater., vol. 14, no. 2, pp. 24-27, 2007.

X. M. Zhang, L. H. Hao and D. M. Jiang, “An Investigation on Tenile Fracture of Al-Mg-Si Alloys,” J. Mater. Eng., vol. 5, pp. 35-36, 1996.

Z. X. Zhou, Y. L. Li and T. Suo. “Microstructure and Dynami Mechanical Properties of 2A14 Aluminium Alloy Sheet,” Mech. Sci. Tech. Aerosp. Eng., vol. 28, no. 11, pp. 1464-1467, 2009, doi: 10.1061/41039(345)45.

L. Wang. Experimental Studies about Dynamic Responses and Fracture Criteria of Q460GJ Structural Steel Considering Stress Triaxiality and Strain-Rate Effects. Chongqing, CHN: Chongqing Univ, 2012.

Y. L. Li. “Definition and Mechanical Characteristics of True Stress-Strain,” J. Chongqing. Univ., vol. 24, no. 3, pp. 58-60, 2001.

Z. Y. Yang, C. C. Zhao, G. J. Dong, “Forming limit research of 5182 aluminum alloy sheet based on Lou-2013 ductile fracture criterion,” J. Mech. ENG., vol. 55, no. 16, pp. 47-57, 2019, doi: 10.13330/j.issn.1000-3940.2017.03.028.

W. C. Li. Research on application of micro-mechanism based fracture theory in fracture prediction analysis of high-strength steel and structures. Xi'an, CHN: Chang'an Univ, 2017.

X. F. Zhu, T. T. Wang, X. C. Zhuang, et al, “Effect of strain path change on ductile fracture of materials,” Forg. Technol., vol. 41, no. 6, pp.122-127, 2016, doi: 10.13330/j.issn.1000-3940.2016.06.023.

H. Kudo, K, Aoi, “Effect of compression test conditions upon fracturing of medium carbon steel,” J. Jap. Soc. Techno. Plastic., vol. 18, pp.17-27, 1967.

F. X. Jin, Z. P. Zhong, F. J. Li, “Influence of Different Hardening Model for the Simulating Results of the Aluminum Alloy Sheet Stamping,” J. Mech. ENG., vol. 53, no. 22, pp.57-66, 2017, doi: 10.3901/JME.2017.22.057.




How to Cite

L. Y. Kou, W. Y. Zhao, X. Y. Tuo, G. Wang, and C. R. Sun, “Effect of stress triaxiality on fracture failure of 6061 aluminium alloy”, J. Mech. Eng. Sci., vol. 14, no. 2, pp. 6961–6970, Jun. 2020.