Failure Prediction in Drawing Processes of Mg Alloy Sheet by the FEM and Ductile Fracture Criterion

2011 ◽  
Vol 264-265 ◽  
pp. 813-818 ◽  
Author(s):  
Sang Woo Kim ◽  
Young Seon Lee ◽  
Beom Soo Kang
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Elevated Temperatures ◽  
Failure Prediction ◽  
Fracture Initiation ◽  
Tensile Tests ◽  
Alloy Sheet ◽  
Fe Analysis ◽  
Uniaxial Tensile ◽  
Ductile Fracture Criterion

In this work, in order to predict the forming failure of AZ31 magnesium alloy sheet in drawing process at elevated temperatures, a series of square cup tests at various temperatures and FE analyses were carried out. The critical damage values and the mechanical properties dependent on strain rates and temperatures were evaluated from uniaxial tensile tests and those were utilized to the forming failure prediction using FE analysis. Based on the plastic deformation history obtained from FE analysis and Cockcroft and Latham’s ductile fracture criterion, the fracture initiation time and location were predicted and verified with the experimental results.

scholarly journals Forming Limit Research of 5182 Aluminum Alloy Sheet Based on Lou-2013 Ductile Fracture Criterion

2019 ◽  
Vol 55 (16) ◽  
pp. 47 ◽  
Author(s):  
YANG Zhuoyun ◽  
ZHAO Changcai ◽  
DONG Guojiang ◽  
CHEN Guang ◽  
ZHU Liangjin ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Ductile Fracture ◽  
Fracture Criterion ◽  
Alloy Sheet ◽  
Forming Limit ◽  
Aluminum Alloy Sheet ◽  
Ductile Fracture Criterion

Prediction of Fracture in Square-Cup Forming of Aluminium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 703-706
Author(s):  
Zhong Qi Yu ◽  
Zhong Qin Lin ◽  
Yu Ying Yang
Keyword(s):  
Aluminium Alloy ◽  
Fracture Behavior ◽  
Fracture Criterion ◽  
High Strength ◽  
Fracture Initiation ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
Ductile Fracture Criterion ◽  
Vehicle Mass ◽  
Experimental Values

Aluminum alloy sheet is becoming one of the main materials to take the place of steel components to reduce the vehicle mass due to the advantage of low special density, high strength and corrosion resistance. To predict the formability during the aluminium alloy sheet forming accurately, , a ductile fracture criterion developed by the authors, was for numerical simulation, in this paper. Fracture behavior in square-cup forming of the aluminium alloy LF21M was predicted by means of the criterion. Comparison of the predicted results with experimental values shows that the critical punch stroke and the fracture initiation position in square-cup forming of the aluminium alloy have been predicted successfully by the criterion.

Experimental Study on the Mechanical Property and Forming Limit of Magnesium Sheet at Elevated Temperatures

2009 ◽  
Author(s):  
Y. Huang ◽  
J. Huang ◽  
J. Cao
Keyword(s):  
Elevated Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Tensile Tests ◽  
Alloy Sheet ◽  
Dome Height ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Magnesium Sheet

Magnesium alloy sheet has received increasing attention in automotive and aerospace industries. It is widely recognized that magnesium sheet has a poor formability at room temperature. While at elevated temperature, its formability can be dramatically improved. Most of work in the field has been working with the magnesium sheet after annealed around 350°C. In this paper, the as-received commercial magnesium sheet (AZ31B-H24) with thickness of 2mm has been experimentally studied without any special heat treatment. Uniaxial tensile tests at room temperature and elevated temperature were first conducted to have a better understanding of the material properties of magnesium sheet (AZ31B-H24). Then, limit dome height (LDH) tests were conducted to capture forming limits of magnesium sheet (AZ31B-H24) at elevated temperatures. An optical method has been introduced to obtain the stress-strain curve at elevated temperatures. Experimental results of the LDH tests were presented.

Evaluation of prediction error resulting from using average state variables in the calibration of ductile fracture criterion

2017 ◽  
Vol 27 (8) ◽  
pp. 1231-1251 ◽  
Author(s):  
Xincun Zhuang ◽  
Yehui Meng ◽  
Zhen Zhao
Keyword(s):  
Ductile Fracture ◽  
Prediction Error ◽  
Fracture Criterion ◽  
Stress Triaxiality ◽  
Fracture Initiation ◽  
Equivalent Strain ◽  
State Variables ◽  
Ductile Fracture Criterion ◽  
Series Of Experiments ◽  
Relationship Of

In order to evaluate the prediction error resulting from using average state variables in the calibration procedure of the ductile fracture criterion, a series of experiments and corresponding simulations were performed to extract the evolution of fracture-related state variables such as stress triaxiality (η), Lode parameter, and equivalent strain to fracture at the fracture initiation points. The average stress triaxiality, average Lode parameter, and equivalent strain to fracture were used to calibrate the Lou-Huh (L-H) ductile fracture criterion. The average induced prediction error was evaluated by comparing the accumulated damage value, which was computed with the calibrated L-H ductile fracture criterion at the fracture initiation point, with the critical threshold value. Comparisons based on a series of experiments covering a wide range of values for stress triaxiality indicated the existence of an average induced prediction error for the compression tests, and demonstrated that different values of embedded-constants C1 and C2 of L-H ductile fracture criterion resulted in entirely different average induced prediction errors. Thus, a parameter study was performed to investigate the influences of C1, C2, the relationship of η and equivalent plastic strain ([Formula: see text]), and the internal function of the integral formula on the average induced relative error. The influence of the relationship of [Formula: see text] could be represented by the influence of the exponent a, the intercept for the stress triaxiality, and the allocation of equivalent strain for the segmented function. Among these influence factors, the value of C2, the value of the exponent a, and the value of the negative intercept for stress triaxiality contributed significantly to an increase in relative error.

Fracture Prediction in Sheet Metal Stamping Based on a Modified Ductile Fracture Criterion

2015 ◽  
Vol 639 ◽  
pp. 543-550
Author(s):  
Rong Zeng ◽  
Liang Huang ◽  
Jian Jun Li
Keyword(s):  
Ductile Fracture ◽  
Sheet Metal ◽  
Fracture Criterion ◽  
Fracture Prediction ◽  
Uniaxial Tensile ◽  
Ductile Fracture Criterion ◽  
Fracture Criteria ◽  
Sheet Metal Stamping ◽  
Ductile Fracture Criteria ◽  
Metal Stamping

Sheet metal stamping is an important manufacturing process because of its high production rate and low cost, so the fracture prediction of stamping parts has become important issues. Recent experimental studies have shown that the quality of stamping parts can be increased by using ductile fracture criteria. This paper proposed a modified ductile fracture criterion based on the macroscopic and microscopic continuum damage mechanics (CDM). Three-dimensional (3D) explicit finite element analysis (FEA) are performed to predict the fracture behaviors of sheet metal stamping process. An approach to determine the material constants of modified ductile fracture criterion is presented with the help of uniaxial tensile tests and compressive tests. The results show that the modified ductile fracture criterion enables precise cup depth and fracture location of sheet metal stamping under nonlinear paths. Compared with typical ductile fracture criteria, the results predicted with modified ductile fracture criterion correlate the best with the experimental data.

Research on Superplasticity of Supplied 5A06 Aluminium Alloy Sheet

2016 ◽  
Vol 838-839 ◽  
pp. 127-131
Author(s):  
Bao Peng Bi ◽  
Yong Wang
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Grain Boundary Sliding ◽  
Strain Rate Range ◽  
Alloy Sheet ◽  
Uniaxial Tensile ◽  
5A06 Aluminum Alloy ◽  
Bulging Test

Superplasticity of supplied 5A06 aluminum alloy is reviewed in this paper. Supplied 5A06 aluminum alloy is researched on superplasticity by the methods of same strain rate high temperature uniaxial tensile tests at temperature range375°C-500°Cand strain rate range 2.5×10-4s-1~1.0×10-2s-1. Microstructure and fracture of tensile samples are analyzed and discussed, deduce that grain boundary sliding (GBS) is the predominant deformation mechanism. Superplastic formability of the alloy is evaluated by gas bulging test at elevated temperatures. Gas bulging test demonstrates the deformation process parameters for the best superplastic formability is 400°Cand 0.005s-1 ,suggesting good application prospect for this aluminum alloy.

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