A Study On Critical Thinning In Thin-walled Tube Bending Of Al-Alloy 5052O Via Coupled Ductile Fracture Criteria

This paper investigates the characteristics of a hydro-mechanical punching process. The hydro-mechanical punching process is divided into two stages: the first stage is the mechanical half piercing in which an upper punch goes down before the initial crack is occurred; the second stage is the hydro punching in which a lower punch goes up until the final fracture is occurred. Ductile fracture criteria such as the Cockcroft et al., Brozzo et al. and Oyane et al. are adopted to predict the fracture of a sheet material. The index value of ductile fracture criteria is calculated with a user material subroutine, VUMAT in the ABAQUS Explicit. The hydrostatic pressure retards the initiation of a crack in the upper region of the blank and induces another crack in the lower region of the blank during the punching process. The final fracture zone is placed at the middle surface of the blank to the thickness direction. The result demonstrates that the hydro-mechanical punching process makes a finer shearing surface than the conventional one as hydrostatic pressure increases.

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Knowledge-based substep deterministic optimization of large diameter thin-walled Al-alloy tube bending

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-013-4811-6 ◽

2013 ◽

Vol 68 (9-12) ◽

pp. 1989-2004 ◽

Cited By ~ 8

Author(s):

H. Li ◽

H. Yang ◽

J. Xu ◽

H. Liu ◽

D. Wang ◽

...

Keyword(s):

Large Diameter ◽

Al Alloy ◽

Tube Bending ◽

Deterministic Optimization ◽

Knowledge Based ◽

Alloy Tube ◽

Thin Walled

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Damage evaluation in tube spinnability test with ductile fracture criteria

International Journal of Mechanical Sciences ◽

10.1016/j.ijmecsci.2015.06.005 ◽

2015 ◽

Vol 100 ◽

pp. 99-111 ◽

Cited By ~ 18

Author(s):

Hao Ma ◽

Wenchen Xu ◽

Bo Cheng Jin ◽

Debin Shan ◽

Steven R. Nutt

Keyword(s):

Ductile Fracture ◽

Damage Evaluation ◽

Fracture Criteria ◽

Ductile Fracture Criteria

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Behavior of Lode Dependent Plasticity at Plane Strain Condition and its Implication to Ductile Fracture

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.258.213 ◽

2016 ◽

Vol 258 ◽

pp. 213-216 ◽

Cited By ~ 1

Author(s):

František Šebek ◽

Jindrich Petruška ◽

Petr Kubík

Keyword(s):

Ductile Fracture ◽

Plane Strain ◽

Uniaxial Stress ◽

Complex Materials ◽

Fracture Criteria ◽

Dependent Plasticity ◽

Ductile Fracture Criteria ◽

Stress States ◽

Aluminum Alloy 2024 ◽

Von Mises

Variety of metals are complex materials exhibiting various behavior under different loading. Many metallic materials exhibit Tresca-like behavior rather than von Mises. It means different behavior in tension under plane strain and uniaxial stress conditions. This might be described by Lode dependent plasticity which should result in better prediction in force or torque responses of material tests. Good agreement between computation and experiment is also very important when calibrating the ductile fracture criteria. Several tests under plane strain and uniaxial stress states were carried out on aluminum alloy 2024-T351 where the Lode dependency was significant. The Lode dependent plasticity was implemented along with von Mises and Tresca-like yield criteria, which resulted in improvement of force–displacement responses of plane strain tests simulations. But it also caused significant change in the stress state of tensile flat and grooved plates which wrongly approached uniaxial tension condition. This inconvenience prevents plane strain experiments from using for calibration of ductile fracture criteria under these circumstances.

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