scholarly journals Research on Ultrasonic-Assisted Multi-Point Stretch Bending Process of Aluminum Profile

Author(s):  
Yi Li ◽  
Zhiheng Hu ◽  
Jicai Liang ◽  
Ce Liang

Abstract The tensile and bending process of asymmetric L-shaped aluminum alloy profile is studied by the Abaqus software using the finite element numerical simulation method. The geometric parameters of the ultrasonic-assisted vibration multi-point die (UMPD), and the law of influence on the stress-strain and spring-back of the L-section profile after bending are studied. The results show that the UMPD can reduce the forming stress of the profile during plastic deformation, and the stress-strain distribution of the aluminum profile is more uniform. The changes in the ultrasonic vibration frequency and amplitude of the mold are beneficial to reduce the spring-back of aluminum profiles. The ultrasonic process parameters with a vibration frequency of 20 kHz and an amplitude of 0.02 mm have the best effect on suppressing spring-back, which is reduced by 20.6% compared to the case of no ultrasonic application. Finally, it is verified by experiments that the experimental results are basically consistent with the simulation results, and the changing trend of spring-back deformation is consistent.

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6057-6063
Author(s):  
YI-DONG BAO ◽  
WEN-LIANG CHEN ◽  
HONG WU

A simplified one-step inverse analysis of sheet metal forming is a suitable tool to simulate the bending forming since the deformation path of bending forming is an approximately proportion one. A fast spring-back simulation method based on one-step analysis is proposed. First, the one-step inverse analysis is applied to obtain the stress distribution at the final stage of bending. Then, the unloading to get a spring back is simulated by LS-DYNA implicit solver. These processes are applied to the unconstrained cylindrical bending and the truck member rail. The spring-back and member rail widths at the several key sections are compared with experimental ones. It is well demonstrated that the proposed method is an effective way to predict the spring-back by unloading after bending process.


Author(s):  
Song Gao ◽  
Tonggui He ◽  
Qihan Li ◽  
Yingli Sun ◽  
Jicai Liang

The problem of springback is one of the most significant factors affecting the forming accuracy for aluminum 3D stretch-bending parts. In order to achieve high-efficiency and high-quality forming of such kind of structural components, the springback behaviors of the AA6082 aluminum profiles are investigated based on the flexible multi-points 3D stretch-bending process (3D FSB). Firstly, a finite element simulation model for the 3D FSB process was developed to analyze the forming procedure and the springback procedure. The forming experiments were carried out for the rectangle-section profile to verify the effectiveness of the simulation model. Secondly, the influence of tension on springback was studied, which include the pre-stretching and the post-stretching. Furthermore, the influences of the bending radius and bending sequence are revealed. The results show that: (1) The numerical model can be used to evaluate the effects of bending radius and process parameters on springback in the 3D FSB process effectively. (2) The pre-stretching has little effect on the horizontal springback reduction, but it plays a prominent role in reducing the springback in the vertical direction. (3) The increase of bending deformation in any direction will lead to an increase of springback in its direction and reduce the springback in the other direction. Besides, it reduces the relative error in both directions simultaneously. This research established a foundation to achieve the precise forming of the 3D stretch-bending parts with closed symmetrical cross-section.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yi Li ◽  
Ce Liang ◽  
Xiangfeng Lin ◽  
Jicai Liang ◽  
Zhongyi Cai ◽  
...  

The springback is one of the main defects in the flexible 3D stretch-bending process. In this paper, according to the orthogonal design of experiments, the numerical simulation analysis of the springback for the 3D stretch-bending aluminum profile is carried out by the ABAQUS finite element software. And to investigate the effect of material properties on the springback, the range analysis of the orthogonal experiment is performed. The results show that these material properties of the aluminum profile (elastic modulus E, yield strength σy, and tangent modulus E1) might have the biggest influence on the springback of the aluminum profile, and the optimized forming parameters are founded as follows: the horizontal bending degree is 14°, the vertical bending degree is 14°, the number of multipoint stretch-bending dies is 10, the friction coefficient is 0.15, and aluminum alloy grade is 6063. Moreover, the model of the BP neural network for the prediction of the springback is established and trained based on the orthogonal experiment, and the results with the BP neural network model are in good agreement with experimental results. So it is obvious that the BP neural network could predict effectively the springback of 3D multipoint stretch-bending parts.


2016 ◽  
Vol 685 ◽  
pp. 133-136 ◽  
Author(s):  
Fedor Grechnikov ◽  
Yurii Gorshkov ◽  
Yaroslav Erisov

We have simulated an aluminum workpiece tool bending process with and without consideration of the heat affected zone after laser cutting with PAM-STAMP 2G. To describe the heat affected zone we have used a customized software option for calculating welded materials and dissimilar ones. We have also provided an analysis of the stress-strain state with a different scale of mechanical properties of the material on its “edge” and in the center of the workpiece.


2010 ◽  
Vol 154-155 ◽  
pp. 202-208 ◽  
Author(s):  
Yi Nan Lai ◽  
Sheng Le Ren ◽  
Zeng Lou Li ◽  
Jun Tao Gu ◽  
Guang Fei Wu

The unloading spring-back of tubes during its manufacturing process shows a strong nonlinearity, which greatly influences the precision of parts. In this paper, the strain distribution of bending tubes was analyzed based on the elasto-plasticity theory, and the theoretical equation for spring-back of tubes was derived. The numerical simulation model for cold tube-bending process was developed with prediction error of 9% compared with experimental results, indicating high reliability of the model. The 12Cr1MoV and 20G tubes were used to analyze the effects of bending angle, bending radius and bending speed on the spring-back of tubes. The prediction equation of spring-back was built, which shows that the spring-back tendency was in accordance with theoretical analysis results. The simulated results show that the spring-back angle is linearly proportional to the bending angle within a certain range. In addition, it is proportional to the relative bending radius and the bending speed.


Author(s):  
Sutasn Thipprakmas ◽  
Pakkawat Komolruji ◽  
Wiriyakorn Phanitwong

In recent years, the requirements for high dimensional precision on Z-bent shaped parts have become increasingly stringent. To attain these requirements, the suitable selection of the Z-die bending type has to be considered much more strictly. In this research, two types of Z-bending processes, offset Z-die bending and wiping Z-die bending, were investigated using the finite element method (FEM) to identify the spring-back characteristics and dimensions of Z-bent shaped parts. In the case of offset Z-die bending, the spring-back characteristics on both bend angles were similar. In contrast, in the case of wiping Z-bending, the spring-back characteristics on both bend angles were different. In addition, the dimensions of the Z-bent shaped parts were investigated. It was found, in the case of wiping Z-bending, that web thinning was generated and the outer bend radius was out of tolerance. To validate the FEM simulation results, experiments were carried out. The FEM simulation results showed good agreement with the experimental results in terms of the bend angles and the overall geometry of the Z-bent shaped parts. To achieve precise Z-bent shaped parts, the suitable selection of Z-die bending type in the Z-die bending process is very important.


Author(s):  
Yafei Wang ◽  
Guangxu Cheng ◽  
Zaoxiao Zhang ◽  
Yun Li ◽  
Jianxiao Zhang

In this paper, the four-roll plate bending process of 2.25Cr-1Mo-0.25V steel at elevated temperature is investigated by numerical simulation. This 3-D simulation is finished by using the elastic-plastic dynamic explicit finite element method (FEM) under the ANSYS/LS-DYNA environment. The strain softening behavior of 2.25Cr-1Mo-0.25V steel at elevated temperature is presented and discussed. The stress-strain relationship of the steel plate is modeled using a piecewise linear material model, with the stress-strain curve obtained through tensile tests. The plate bending process with a plate thickness of 150 mm is investigated. The amount and position of maximum plastic deformation are analyzed. The present study provides an important basis for the optimization of bending parameters and further investigation of the effect of high-temperature deformation on the resistance to hydrogen attack of 2.25Cr-1Mo-0.25V steel.


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