Inward Flow of Surface Materials at Back-Ends of Billets During Al-Extrusion, Part 1: A Finite Element Model

1999 ◽  
Vol 121 (3) ◽  
pp. 321-327 ◽  
Author(s):  
Jin Hou

In hot extrusion of Al-profiles, the billet-container boundary is characterized by the sticking condition. The outer surface layer of the billet is stuck to the container wall. At the back-end of the billet, the metal flow is complicated. The surface material, which is initially stuck to the wall, will be scraped away by the pad and flow inward into the billet. This kind of inward flow of surface material is usually undesirable and it is important to control such flow so that no surface material should be found in extruded profiles. In order to study this phenomenon, a model is proposed for the metal flow at the back-end, in which the rigid-plastic FEM is used. A computer program FEMBA has been developed based on the model. The simulation results are in qualitatively good agreement with experiments.

2021 ◽  
Author(s):  
Sandeep Dhar

The trajectory of an angular particle as it cuts a ductile target is, in general, complicated because of its dependence not only on particle shape, but also on particle orientation at the initial instant of impact. This orientation dependence has also made experimental measurement of impact parameters of single angular particles very difficult, resulting in a relatively small amount of available experimental data in the literature. The current work is focused on obtaining measurements of particle kinematics for comparison to rigid plastic model developed by Papini and Spelt. Fundamental mechanisms of material removal are identified, and measurements of rebound parameters and corresponding crater dimensions of single hardened steel particles launched against flat aluminium alloy targets are presented. Also a 2-D finite element model is developed and a dynamic analysis is performed to predict the erosion mechanism. Overall, a good agreement was found among the experimental results, rigid-plastic model predictions and finite element model predictions.


2021 ◽  
Vol 13 (1) ◽  
pp. 131-139
Author(s):  
Luhan Hao ◽  
Tao Wang ◽  
Kangping Fu ◽  
Zhengyang Zhao ◽  
Yun Chen ◽  
...  

In order to study the forming law of the disc cutter ring in the independently researched die, the finite element model (FEM) of disc cutter ring for die forging has been established and the die forging process has been simulated by the plastic forming software. The metal flow field, temperature field, stress and strain field of the filling process were obtained by simulation. The exerted force of the die was also simulated and analyzed; thus, the die forging process was optimized. Based on the designed process parameters and simulation results, the experimental study on die forging forming of cutter ring was carried out. The comparison shows that the numerical simulation results are in good agreement with the experimental results, which proves that the die forging model of disc cutter ring in this paper is feasible.


2021 ◽  
Author(s):  
Sandeep Dhar

The trajectory of an angular particle as it cuts a ductile target is, in general, complicated because of its dependence not only on particle shape, but also on particle orientation at the initial instant of impact. This orientation dependence has also made experimental measurement of impact parameters of single angular particles very difficult, resulting in a relatively small amount of available experimental data in the literature. The current work is focused on obtaining measurements of particle kinematics for comparison to rigid plastic model developed by Papini and Spelt. Fundamental mechanisms of material removal are identified, and measurements of rebound parameters and corresponding crater dimensions of single hardened steel particles launched against flat aluminium alloy targets are presented. Also a 2-D finite element model is developed and a dynamic analysis is performed to predict the erosion mechanism. Overall, a good agreement was found among the experimental results, rigid-plastic model predictions and finite element model predictions.


2014 ◽  
Vol 941-944 ◽  
pp. 1895-1900 ◽  
Author(s):  
Fa Shen ◽  
Wen Jing Yu ◽  
Wen Fei Peng ◽  
Xue Dao Shu ◽  
Chun Jie Yu

The spiral shaft parts have been widely applied in machinery and equipment manufacturing industry, the paper based on DEFORM-3D, the rigid-plastic finite element model of cross wedge rolled spiral shaft parts was established. The rolling process was simulated, the strain laws were analyzed, and the characteristics of metal flow were explored. From which we can find Plate cross wedge rolled spiral shaft parts is completely feasible. The results provide the theoretic basis for precision deformation of cross wedge rolled spiral shaft parts.


2012 ◽  
Vol 468-471 ◽  
pp. 456-460
Author(s):  
M. Sedighi ◽  
M. Khandaei ◽  
M.A> Liaghat

This paper presents an approach for modification a FEM simulation of electromagnetic tube compression process which has been presented by Mamalis. Electromagnetic free compression of a tube inside a coil has been simulated by using elements with coupled DOFs of electrical and magnetic potentials and displacement components. Mamalis's simulation results show a degree of disagreement with experimental results. In the present work, the coil has been modeled as separate parallel rings and a new correction factor has been determined for the current load applied on the coil. Comparison between simulation and experimental results shows a good agreement at the middle of workpiece with a reasonable error at workpiece ends.


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.


2011 ◽  
Vol 230-232 ◽  
pp. 352-356
Author(s):  
Wen Ke Liu ◽  
Kang Sheng Zhang ◽  
Zheng Huan Hu

Based on the rigid-plastic deformation finite element method and the heat transfer theories, the forming process of cross wedge rolling was simulated with the finite element software DEFORM-3D. The temperature field of the rolled piece during the forming process was analyzed. The results show that the temperature gradient in the outer of the work-piece is sometimes very large and temperature near the contact deformation zone is the lowest while temperature near the center of the rolled-piece keeps relatively stable and even rises slightly. Research results provide a basis for further study on metal flow and accurate shaping of work-piece during cross wedge rolling.


2011 ◽  
Vol 189-193 ◽  
pp. 2535-2538 ◽  
Author(s):  
Hong Yan ◽  
Wen Xian Huang

The thixo-forging of magnesium matrix composite was analyzed with computer numerical simulation based on rigid viscoplastic finite element method. The constitutive model of SiCp/AZ61 composite was established in our prior literature. Behavior of metal flow and temperature field were obtained. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that thixo-forging was better in filling cavity than forging. Simulation results were good agreement with experimental ones.


Author(s):  
Lý Hùng Anh ◽  
Nguyễn Phụ Thượng Lưu ◽  
Nguyễn Thiên Phú ◽  
Trần Đình Nhật

The experimental method used in a frontal crash of cars costs much time and expense. Therefore, numerical simulation in crashworthiness is widely applied in the world. The completed car models contain a lot of parts which provided complicated structure, especially the rear of car models do not contribute to behavior of frontal crash which usually evaluates injuries of pedestrian or motorcyclist. In order to save time and resources, a simplification of the car models for research simulations is essential with the goal of reducing approximately 50% of car model elements and nodes. This study aims to construct the finite element models of front structures of vehicle based on the original finite element models. Those new car models must be maintained important values such as mass and center of gravity position. By using condition boundaries, inertia moment is kept unchanged on new model. The original car models, which are provided by the National Crash Analysis Center (NCAC), validated by using results from experimental crash tests. The modified (simplistic) vehicle FE models are validated by comparing simulation results with experimental data and simulation results of the original vehicle finite element models. LS-Dyna software provides convenient tools and very strong to modify finite element model. There are six car models reconstructed in this research, including 1 Pick-up, 2 SUV and 3 Sedan. Because car models were not the main object to evaluate in a crash, energy and behavior of frontal part have the most important role. As a result, six simplified car models gave reasonable outcomes and reduced significantly the number of nodes and elements. Therefore, the simulation time is also reduced a lot. Simplified car models can be applied to the upcoming frontal simulations.


2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Jagoba Lekue ◽  
Florian Dörner ◽  
Christian Schindler

This paper presents research activities regarding the systematic error of the pressure measurement film when measuring the area of the wheel–rail contact. In particular, an explanation for the different error values shown by the different film types was sought. A finite element model was created based on the assumption that not only the film, but also the microcapsules on top of it alter the results. The performance of the existing film models was enhanced by defining microcapsules with element failure and deletion behaviors. The new model was capable of reproducing the trend shown by the systematic error in the experiments. The simulation results confirmed that the measurement error of a certain film type is not only caused by the film itself, but also depends on the failure pressure and especially the diameter of the capsules.


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