scholarly journals Ductile Fracture Prediction in Cross-Wedge Rolling of Rail Axles

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6638
Author(s):  
Tomasz Bulzak
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Effective Strain ◽  
Thermal Conditions ◽  
Ductile Fracture Criterion ◽  
Fracture Criteria ◽  
Cross Wedge Rolling ◽  
Fracture Force ◽  
Advantages And Disadvantages ◽  
Material Fracture

In the process of cross-wedge rolling, axial-symmetric forgings are formed using wedge tools. These tools may be flat- or roll-shaped. This article presents two methods of cross-wedge rolling of rail axles, traditional and multi-wedge, as well as their advantages and disadvantages. Two cross-wedge rolling processes are modelled numerically using Simufact Forming. Numerical results are then verified by experiments performed on a flat wedge rolling mill. Results obtained with the two rolling methods are compared in terms of material fracture, force parameters, effective strain and thermal conditions during rolling. Results show that material fracture poses a serious problem in these rolling processes. It is found that the Cockcroft–Latham ductile fracture criterion does not predict material fracture correctly. Results demonstrate that the fracture of railway axles in cross-wedge rolling can be best predicted by the fracture criteria developed by Ayada, Brozzo, Ko, Rice and Tracey.

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.

A Note on Ductile Fracture Criteria in Metal Forming

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Sergei Alexandrov ◽  
Lihui Lang
Keyword(s):  
Ductile Fracture ◽  
Metal Forming ◽  
Fracture Criterion ◽  
Ductile Fracture Criterion ◽  
Hot Metal ◽  
Fracture Criteria ◽  
Material Models ◽  
Analysis And Design ◽  
Ductile Fracture Criteria ◽  
Forming Analysis

This paper deals with some general properties of a ductile fracture criterion, which generalizes two ductile fracture criteria conventionally adopted for metal forming analysis and design. The results are valid for a wide class of material models applicable to both cold and hot metal formings. It is expected that the theoretical features of the fracture criterion emphasized in the present paper can be useful for its experimental verification or for determining its parameters from the experiment.

The Method to Determine Material Constants in Ductile Fracture Criterion

2018 ◽  
Vol 279 ◽  
pp. 85-91
Author(s):  
Jun Wei ◽  
Lian Fa Yang ◽  
Jian Guo
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Integral Form ◽  
Simulation Method ◽  
Theory Model ◽  
Ductile Fracture Criterion ◽  
Forming Process ◽  
Material Constants ◽  
Plastic Forming ◽  
Material Fracture

In the metal plastic forming process, ductile fracture is an important factor influencing the forming properties of materials, and the ductile fracture criterion can effectively predict the moment and location when the material fracture. When using the ductile fracture criterion predicts the fracture of materials, the material constants expressed in integral form is an important index that affect the prediction accuracy. At present, the method to determine the material constants in the ductile fracture criterion is mostly combined with basic test. Therefore, the method to determine the material constants in ductile fracture criterion is introduced in this paper. These methods are divided into numerical calculation methods, finite element simulation method and the M-K theory model method.

Evaluation of Seven Ductile Fracture Criteria for Failure Prediction of AZ31 Sheet in Warm Forming

2012 ◽  
Vol 482-484 ◽  
pp. 1947-1950 ◽  
Author(s):  
Jian Guang Liu ◽  
Wei Liu
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Alloy Sheet ◽  
Mg Alloy ◽  
Ductile Fracture Criterion ◽  
Fracture Criteria ◽  
Ductile Fracture Criteria ◽  
Element Simulation ◽  
Az31 Mg Alloy ◽  
Az31 Sheet

Seven commonly used ductile fracture criteria are briefly reviewed and the validity of predicting the failure of AZ31 Mg alloy sheet by using these ductile fracture criteria is evaluated. Through fitting the experimental FLCs, the damage parameters for these ductile fracture criteria are determined firstly. Integrating these seven ductile fracture criteria into Abaqus/Explicit via VUMAT subroutine, the warm deep drawing process of AZ31 Mg alloy sheet is simulated. The limit drawing ratios (LDR) of AZ31 Mg alloy sheet at different temperature are predicted. The comparison of predictions with the experimental results has shown that the combination of the finite element simulation and the ductile fracture criterion is useful for predicting the fracture occurred in warm deepdrawing of AZ31 Mg alloy sheet.

scholarly journals Comparison of Modified Mohr–Coulomb Model and Bai–Wierzbicki Model for Constructing 3D Ductile Fracture Envelope of AA6063

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jianye Gao ◽  
Tao He ◽  
Yuanming Huo ◽  
Miao Song ◽  
Tingting Yao ◽  
...  
Keyword(s):  
Ductile Fracture ◽  
Fracture Criterion ◽  
Fracture Strain ◽  
Stress Triaxiality ◽  
Ductile Fracture Criterion ◽  
Forming Process ◽  
Tension Tests ◽  
Wide Range ◽  
Round Bar ◽  
Fracture Envelope

AbstractDuctile fracture of metal often occurs in the plastic forming process of parts. The establishment of ductile fracture criterion can effectively guide the selection of process parameters and avoid ductile fracture of parts during machining. The 3D ductile fracture envelope of AA6063-T6 was developed to predict and prevent its fracture. Smooth round bar tension tests were performed to characterize the flow stress, and a series of experiments were conducted to characterize the ductile fracture firstly, such as notched round bar tension tests, compression tests and torsion tests. These tests cover a wide range of stress triaxiality (ST) and Lode parameter (LP) to calibrate the ductile fracture criterion. Plasticity modeling was performed, and the predicted results were compared with corresponding experimental data to verify the plasticity model after these experiments. Then the relationship between ductile fracture strain and ST with LP was constructed using the modified Mohr–Coulomb (MMC) model and Bai-Wierzbicki (BW) model to develop the 3D ductile fracture envelope. Finally, two ductile damage models were proposed based on the 3D fracture envelope of AA6063. Through the comparison of the two models, it was found that BW model had better fitting effect, and the sum of squares of residual error of BW model was 0.9901. The two models had relatively large errors in predicting the fracture strain of SRB tensile test and torsion test, but both of the predicting error of both two models were within the acceptable range of 15%. In the process of finite element simulation, the evolution process of ductile fracture can be well simulated by the two models. However, BW model can predict the location of fracture more accurately than MMC model.

scholarly journals Finite Element Analysis of Bore-expanding Processes with Ductile Fracture Criterion

1998 ◽  
Vol 84 (3) ◽  
pp. 182-187 ◽  
Author(s):  
Hirohiko TAKUDA ◽  
Ken-ichiro MORI ◽  
Masashi KANESHIRO ◽  
Natsuo HATTA
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ductile Fracture ◽  
Fracture Criterion ◽  
Ductile Fracture Criterion ◽  
Element Analysis
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