FEM-Based Simulation and Gripper Jaw Trajectory Fitting of Stretch-Bending Process for a Bending Beam of Railway Vehicles

2013 ◽  
Vol 372 ◽  
pp. 661-665
Author(s):  
Sheng Man Wang ◽  
Xin Hua Yang ◽  
Xing Lu
Keyword(s):  
Control Method ◽  
Die Design ◽  
Railway Vehicle ◽  
Fe Model ◽  
The Finite Element Method ◽  
Forming Process ◽  
Stretch Bending ◽  
Bending Process ◽  
Design Requirements ◽  
Displacement Control Method

The bending beam of railway vehicle is made of thin stainless steel, with large sizes and unsymmetrical section, and prone to defects during stretch-bending forming process, such as wrinkling, cross-section distortion and so on. A reasonable trajectory of gripper jaws could make for mitigating the mentioned defects. The Finite Element Method was employed to fit the trajectory as well as simulate the forming process. The FE model was built by using the commercial FE software Hypermesh and ABAQUS/CAE. The analysis was carried out based on dynamic explicit and displacement control method. On this basis, the actual stretch bending process was developed according to the fitted trajectory and simulated process. The actual production process indicates that the formed beam can meet the design requirements, and the method is feasible and economical, as well as can contribute to a better understanding of stretch bending process and die design.

Warm forming process for an AA5754 train window panel

2021 ◽  
pp. 1-32
Author(s):  
Antonio Piccininni ◽  
Andrea Lo Franco ◽  
Gianfranco Palumbo
Keyword(s):  
Material Characterization ◽  
Room Temperature ◽  
Warm Forming ◽  
Railway Vehicle ◽  
Fe Model ◽  
Forming Process ◽  
Vehicle Component ◽  
Mechanical Approach ◽  
Thermal Simulations ◽  
Critical Regions

Abstract A warm forming process is designed for AA5754 to overcome low room temperature formability. The solution includes increased working temperature and is demonstrated with a railway vehicle component. A Finite Element (FE) based methodology was adopted to design the process taking into account also the starting condition of the alloy. In fact, the component's dent resistance can be enhanced if the yield point is increased accordingly: the stamping process was thus designed considering the blank in both the H111 (annealed and slightly hardened) and H32 (strain-hardened and stabilized) conditions that were preliminarily characterized. Tensile and formability tests were carried out at different temperature and strain rate levels, thus providing the data to be implemented within the FE model (Abaqus/CAE): the stamping was at first simulated at room temperature to evaluate the blank critical regions. Subsequently, the warm forming process was designed by means of an uncoupled thermo-mechanical approach. Thermal simulations were run to properly design the heating strategy and achieve an optimal temperature distribution over the blank deformation zone (according to the results of the material characterization). Such a distribution was then imported as a boundary condition into the mechanical step (Abaqus/Explicit) to determine the optimal process parameters and obtain a sound component (strain severity was monitored implementing an FLD-based damage criterion). The simulation model was validated experimentally with stamping trials to fabricate a sound component using the optimized heating strategy and punch stroke profile.

Study on the Intelligent Control of Springback in Stretch Bending Process Based on Neural Networks

2006 ◽  
Vol 532-533 ◽  
pp. 604-607
Author(s):  
Yong Jun Wang ◽  
Jun Biao Wang ◽  
Sheng Min Wei ◽  
Jiang Jun Jiang
Keyword(s):  
Mechanical Properties ◽  
Neural Networks ◽  
Friction Coefficient ◽  
Intelligent Control ◽  
Process Parameters ◽  
Control Method ◽  
Friction Condition ◽  
Whole Process ◽  
Stretch Bending ◽  
Bending Process

In extrusion stretch bending process, there are many factors which affect springback of the workpiece such as mechanical properties of the material, friction condition and process parameters. The springback of same batch of extrusion is different at same forming parameters because of the variation of the mechanical properties of the material and the friction condition. A method of intelligent control of springback in stretch bending process is proposed by using ANN(artificial neural networks). The online identification model of the mechanical properties of the material and friction coefficient and the online prediction control model of springback of workpiece in stretch bending process are established by using ANN ,which are trained by the data of analysis calculation. It realizes the intelligent control on springback of stretch bending to online identify the material properties and friction coefficient and predict springback and adjust process parameters dynamically through the whole process of stretch bending. The results from the experiment state that the intelligent control method can suit the variation of mechanical properties of material and friction condition and improve the geometry precision.

Research on Bending Process of Integral Panel Skins

2011 ◽  
Vol 299-300 ◽  
pp. 1048-1051
Author(s):  
Jin Song Liu ◽  
Ying Guo ◽  
Shi Hong Zhang ◽  
Han Xiao
Keyword(s):  
Finite Element Method ◽  
Simple Structure ◽  
Incremental Forming ◽  
Aerospace Industry ◽  
Light Weight ◽  
The Finite Element Method ◽  
Forming Process ◽  
Roll Bending ◽  
Bending Process ◽  
High Structure

With the advantages such as light weight, high structure intensity and good rigidity, integral panel skins have been widely applied in aerospace industry. The forming process of mechanical milling-filling auxiliary roll bending and the incremental bending of integral panel skins were proposed based on the finite element method and the experiments technique. The research shows that the shapes of panel skins were binded by the ribs plastic deformation. The roll bending was suitable to the panel skins with the low ribs or the simple structure. The incremental forming was suitable to the panel skins with the high ribs or the involutes structure.

Spring-Back Evaluation of Stretch Bending Process Based on Chaboche Combined Isotropic-Kinematic Hardening Laws

2011 ◽  
Vol 204-210 ◽  
pp. 1745-1750 ◽  
Author(s):  
Jing Hu ◽  
Xiao Xing Li ◽  
Kwan Soo Chung ◽  
Rao Yao
Keyword(s):  
Kinematic Hardening ◽  
Spring Back ◽  
Stretch Forming ◽  
Forming Process ◽  
Hardening Law ◽  
Stretch Bending ◽  
User Subroutine ◽  
Bending Process ◽  
Chaboche Model ◽  
Simulation Results

We present a study on spring-back prediction in the stretching bending process using the Chaboche model combined isotropic-kinematic hardening law and Mises yielding criterion, and a material user subroutine (VUMAT, UMAT) program was developed base on the ABAQUS interface for the model. The effects of different hardening law on the spring-back in the stretch forming process was also analyzed and compared. The simulation results show that the combined isotropic-kinematic hardening law has the better spring-back prediction compared with the pure isotropic and kinematic hardening law in the stretch forming process, which is verified by the experimental results.

Experimental Investigation on the Residual Stresses Induced by a Plastic Forming Process

2010 ◽  
Vol 452-453 ◽  
pp. 821-824 ◽  
Author(s):  
Giuseppe Lamanna ◽  
Luigi Grassia ◽  
Vascione Ascione
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Trial And Error ◽  
Forming Process ◽  
Cross Sectional ◽  
Residual Stress State ◽  
Stretch Bending ◽  
Bending Process ◽  
Plastic Forming

The extrusion of a space frame must be followed by forming operations of some kind to obtain the desired shape/curvature, for example a stretch bending process. Therefore, one has to face with problems as production tolerances and cross-sectional distortions of the curved product. In house experience combined with trial–and–error procedures have been traditionally used to cope with the said problems. Aircraft frames show significant residual stresses as a consequence of plastic forming processes. A great number of variables, such as initial frame length and/or final additional stretch, can influence the stress state of frames determining their life and efficiency under operating loading conditions. In the present paper, we refer about the experimental evaluations of the residual stress state of aircraft frames which have carried out taking into account different process parameters. The experimental results obtained and discussed show some interesting trends: they demonstrate that the residual stresses of the formed component can be controlled and reduced.

scholarly journals Evaluation of the sensitivity of springback to various process parameters of aluminum alloy sheet with different heat treatment conditions

2021 ◽  
Vol 9 (3) ◽  
pp. 323-334 ◽  
Author(s):  
S. Hakimi ◽  
A. Soualem
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Boundary Conditions ◽  
Process Parameters ◽  
Hold Time ◽  
Testing Machine ◽  
Fe Model ◽  
Tensile Testing Machine ◽  
Stretch Bending ◽  
Bending Process

The forming steps by permanent deformation controlled by the tools generate a distribution of stresses inside the material which directly depends on the work hardening properties of the latter. The change in boundary conditions following the removal of the tools imposes the material to redistribute the stresses in the sections in a manner compatible with the new boundary conditions. This new distribution necessarily operates by local elastic deformations that result globally in a general change of shape called springback. This geometrical deviation can be minimized by the meticulous focus of the tools, but it cannot generally be completely annihilated due to the influence of several parameters. For this reason, the study of the influence of the different technological factors and physico-metallurgical parameters on the springback for the different metals is very important to design and properly realize forming tools. The main objective of this work is to find solutions to problems encountered in sheet metal forming such as the problem of springback. Our work has two essential purposes: the first is summarized in an experimental study based on theoretical analyses. To this end, much effort is made to add a new design of parts for a U-type stretch-bending device and adapt it to a tensile testing machine. This design has the advantage of modifying and assembling all parameters affecting springback at the same time and also of carrying out several forming processes on the same device. The second goal is the experimental and numerical prediction of springback, and the study of the effect of various stretch-bending process parameters such as punch velocity, the orientation of the sheet (anisotropy), hold time and punch-die clearance on springback behavior under heat treatment of aluminum alloy sheets with three different rolling directions (0°,45°,90°). A finite element (FE) model of stretch-bending has been established by utilizing ABAQUS/CAE software. From this analysis, it can be concluded that the springback is affected by the anisotropy of the sheet and the heat treatment in the stretch-bending process. The obtained experimental results were compared with the numerical simulations found in good agreement.

Dynamic FE Analysis for Reducing the Flat Areas of Formed Shapes Obtained by Roll Bending Process

2013 ◽  
Author(s):  
Hoang Quan Tran ◽  
Henri Champliaud ◽  
Zhengkun Feng ◽  
Thien-My Dao
Keyword(s):  
Rolling Direction ◽  
Vertical Displacement ◽  
Fe Model ◽  
Forming Process ◽  
Dynamic Simulations ◽  
Continuous Forming ◽  
Flat Area ◽  
Roll Bending ◽  
Bending Process ◽  
Bottom Roll

Roll bending is a continuous forming process where plates, sheets, beams, pipes, and even rolled shapes and extrusions are bent to a desired curvature using forming rolls. Over the years, with the advantages such as reducing setting up time, the cost in tooling investment and equipment, the roll bending process was fundamental for manufacturing cylindrical shapes. However, the process always leaves a flat area along the leading and trailing edges of the workpiece. Therefore, accuracy could be a challenge when the part to be produced is large and made of high strength steel. There are several methods to minimize the flat area. Among them, for the asymmetrical configuration, moving slightly the bottom roll along the rolling direction may have the highest effect. On the other hand local adjustment of the bottom roll location is also important for providing the pressure needed for gripping and carrying the workpiece through the rolls. Then by optimizing the vertical displacement of the bottom roll one can minimize the span of flat areas. The main objective of this research is to assess 3D dynamic Finite Element (FE) model with Ansys/LS-Dyna for the simulation and analysis of the deformation of the workpiece during the manufacturing of cylindrical parts. Various dynamic simulations based on 3D element are performed to provide better understanding of the whole deformation history and to establish the relationship between the location of the bottom roll and the end shapes of the formed cylinders. The results from FE simulations are then compared with corresponding experimental results from an industrial roll bending machine in order to improve the quality of the final shape.

Research on springback characteristic in flexible multi-points 3D stretch-bending process

2021 ◽  
pp. 095440542110284
Author(s):  
Song Gao ◽  
Tonggui He ◽  
Qihan Li ◽  
Yingli Sun ◽  
Jicai Liang
Keyword(s):  
Simulation Model ◽  
High Efficiency ◽  
Vertical Direction ◽  
Factors Affecting ◽  
Stretch Bending ◽  
Element Simulation ◽  
Bending Process ◽  
Bending Radius ◽  
Aluminum Profiles ◽  
Bending Sequence

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.

Exploration on Shape of Profiles Determined by Chord Angle Control Method

2011 ◽  
Vol 314-316 ◽  
pp. 837-841
Author(s):  
Ling Ling ◽  
Yuan Sheng Zeng
Keyword(s):  
Theoretical Basis ◽  
Control Method ◽  
Angle Measurement ◽  
Mapping Method ◽  
Control Methods ◽  
Forming Process ◽  
Spline Curve ◽  
Curve Line ◽  
Line Measure

Through compassion of relative merits of the existing two control methods of straighten anti-curve line and chord line measure for cold-formed profiles, a three-pivot chord angle control method of non-endpoint measurement was proposed in this paper, and its feasibility was proved by using mathematical deduction. Using mapping method, the forming of profiles can be controlled by the only one set of orderly array chord angles and chord lines obtained by a spline curve of profiles, and meanwhile, the length of automation feedstock in forming process of profiles was explored. The present research achievements can provide a good theoretical basis for the further application on controlling profile forming with the chord angle measurement.

Experimental Assessment of High Temperature Formability of Boron Steel Sheet Manufactured With a Spring Compound Bending Die

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Yang Li ◽  
Yong-Phil Jeon ◽  
Chung-Gil Kang
Keyword(s):  
Mechanical Properties ◽  
Heating Temperature ◽  
Boron Steel ◽  
Hot Press ◽  
Forming Process ◽  
Steel Sheets ◽  
Press Forming ◽  
Bending Process ◽  
Tension Testing ◽  
Hot Press Forming

Bending behavior occurs in the hot press forming process, resulting in many cases of failure during forming. To address the problem of cracking and improve the formability and mechanical properties of boron steel sheets in the bending process, an experiment has been carried out by using a spring compound bending die. Also, a comparison has been made between the traditional U-bending die and the spring compound bending die with regard to formability. The influence of the parameters for hot press forming such as the heating temperature, punch speed, and die radii on the mechanical properties and microstructure was analyzed by tension testing and metallographic observations.

Sign in / Sign up

Export Citation Format

Share Document