scholarly journals THE FINITE ELEMENT PREDICTION OF DUCTILE FRACTURE INITIATION IN DYNAMIC METALFORMING PROCESSES

1991 ◽  
Vol 01 (C3) ◽  
pp. C3-751-C3-757
Author(s):  
Y. Y. ZHU ◽  
S. CESCOTTO
1999 ◽  
Vol 122 (3) ◽  
pp. 476-483 ◽  
Author(s):  
A. M. Goijaerts ◽  
L. E. Govaert ◽  
F. P. T. Baaijens

This study is focused on the description of ductile fracture initiation, which is needed to predict product shapes in the blanking process. Two approaches are elaborated using a local ductile fracture model. According to literature, characterization of such a model should take place under loading conditions, comparable to the application. Therefore, the first approach incorporates the characterization of a ductile fracture model in a blanking experiment. The second approach is more favorable for industry. In this approach a tensile test is used to characterize the fracture model, instead of a complex and elaborate blanking experiment. Finite element simulations and blanking experiments are performed for five different clearances to validate both approaches. In conclusion it can be stated that for the investigated material, the first approach gives very good results within the experimental error. The second approach, the more favorable one for industry, yields results within 6 percent of the experiments over a wide, industrial range of clearances, when a newly proposed criterion is used. [S1087-1357(00)02202-4]


Author(s):  
W. Rekik ◽  
O. Ancelet ◽  
C. Gardin

This work deals with the characterization of ductile damage in Aluminum 6061-T6 alloy. In this paper we discuss the stress triaxiality effect on the initiation and the evolution of damage through a sequence of tensile tests conducted on round specimens with different rate of trixialities and tearing tests on precracked Compact Tension specimens. Scattering of ductility and toughness values was highlighted between the three characteristic directions studied in this topic. Based on the experimental results, numerical simulation has been performed in order to analyze and predict ductile fracture initiation of this aluminum alloy by simulating void growth according to the Rice-Tracey micromechanical model. The numerical simulation was conducted in two steps: first the critical void growth ratio (R / R0)c was evaluated for tensile cylindrical specimens with different degrees of triaxiality and then used to analyze crack growth initiation on Compact Tension specimen. Due to the Al-6061-T6 highly sensitivity to triaxiality, a necessary adaptation of the Rice-Tracey model’s coefficient was made.


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