Effect of hardening models on different ductile fracture criteria in sheet metal forming

2014 ◽  
Vol 9 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Shahram Abbasnejad Dizaji ◽  
Haluk Darendeliler ◽  
Bilgin Kaftanoğlu
Keyword(s):  
Ductile Fracture ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Fracture Criteria ◽  
Ductile Fracture Criteria ◽  
Hardening Models

The Evaluation of Ductile Fracture Criteria (DFC) of 6061-T6 Aluminum Alloy

2010 ◽  
Vol 44-47 ◽  
pp. 2837-2841 ◽  
Author(s):  
Ying Tong
Keyword(s):  
Aluminum Alloy ◽  
Ductile Fracture ◽  
Metal Forming ◽  
True Strain ◽  
Mutual Support ◽  
Fracture Criteria ◽  
Forming Process ◽  
Forming Simulation ◽  
Ductile Fracture Criteria ◽  
Metal Forming Process

As one of the principal failures, ductile fracturing restricts metal forming process. Cockcroft-Latham fracture criterion is suited for tenacity fracture in bulk metal-forming simulation. An innovative approach involving physical compression experiments, numerical simulations and mathematic computations provides mutual support to evaluate ductile damage cumulating process and ductile fracture criteria (DFC). The results show that the maximum cumulated damage decreases with strain rate rising, and the incremental ratios, that is damage sensitive rate, vary uniformly during the upsetting processes at different strain rates. The damage sensitive rate decreases rapidly, then it becomes stability in a constant 0.11 after true strain -0.85. The true strain -0.85 was assumed as the fracture strain, and the DFC of 6061-T6 aluminum alloy is almost a constant 0.2. According to DFC, the exact fracture moment and position during various forming processes will be predicted conveniently.

Prediction and analysis of ductile fracture in sheet metal forming—Part I: A modified Ayada criterion

2014 ◽  
Vol 23 (8) ◽  
pp. 1189-1210 ◽  
Author(s):  
HS Liu ◽  
MW Fu
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Ductile Fracture ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Fracture Criterion ◽  
Ductile Fracture Criterion ◽  
Wide Range ◽  
Stress States

A modified ductile fracture criterion is proposed based on the traditional Ayada criterion and coded into the finite element simulation platform of VUMAT/ABAQUS for prediction and analysis of ductile fracture in metal plastic strain processes. In this modified ductile fracture criterion, stress triaxiality is taken into account, and more importantly, the exponential effect of the equivalent plastic strain on the damage behavior, which is generally ignored in other ductile fracture criteria, is also considered. The material related constants in the modified ductile fracture criterion are determined by tensile tests together with finite element simulations. The applicability and reliability of the ductile fracture criterion in ductile fracture prediction in two types of classic stress states, viz. shear stress, tensile stress in sheet metal forming, are investigated based on the deformation behavior and fracture occurrence in two case studies with two typical types of materials, i.e. Al 6061 and T10A. The materials have a wide range of plasticity. The simulation and experimental results verify the applicability and reliability of the developed ductile fracture criterion in prediction of the ductile fracture with and without necking in different stress states of plastic strain.

Sign in / Sign up

Export Citation Format

Share Document