The Effect of the Initial Stress and Strain State in Sheet Metals on the Roller Levelling Process

2015 ◽  
Vol 651-653 ◽  
pp. 1023-1028 ◽  
Author(s):  
Markus Grüber ◽  
Marius Oligschläger ◽  
Gerhard Hirt
Keyword(s):  
Process Control ◽  
Initial Stress ◽  
Sheet Metal ◽  
Process Parameters ◽  
Kinematic Hardening ◽  
Sheet Material ◽  
Stress And Strain ◽  
Fe Model ◽  
Sheet Metals ◽  
Initial State

Due to increasing requirements regarding the flatness of sheet metals, the process of roller levelling is of particular importance. The process itself is influenced by a high number of parameters such as machine design, sheet dimension, and material properties. Therefore, it is desirable to provide an online process control to react on changes of those process parameters. One possible approach for the layout of a process control and the identification of reference values is the use of the Finite Element Method (FEM). Considering the alternate bending a sheet metal undergoes when passing through a roller leveller, kinematic hardening of the sheet material must be taken into account. Additionally, the initial stress and strain distribution of the sheet metal – e.g. induced by coiling – has an influence on the material behaviour and consequently on the process parameters. With respect to these effects, a coupled FE model, which accounts for the initial state of the sheet metal, is introduced. An inverse calculation of material parameters describing the behaviour under cyclic load conditions has been done for an aluminium alloy AA5005 and a mild steel DC01. Based on this numerical setup, the influence of the initial stress state in the pre-levelled sheet metal on the roller levelling process has been deduced. Accompanying experiments on a down-sized roller leveller were carried out for a validation of the numerical setup.

Springback Analysis of Aluminum Alloy Sheet Metals by Yoshida-Uemori Model

2016 ◽  
Vol 725 ◽  
pp. 566-571 ◽  
Author(s):  
Takeshi Uemori ◽  
Kento Fujii ◽  
Toshiya Nakata ◽  
Shinobu Narita ◽  
Naoya Tada ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Sheet Metal ◽  
Kinematic Hardening ◽  
Yield Function ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
Sheet Metals ◽  
Initial Anisotropy ◽  
Hardening Rules ◽  
Prediction Capability

During the last few decades, the enhancement of prediction capability of the sheet metal forming have been increasing dramatically. High accurate yield criteria and wokhardening model (especially, non-linear kinematic hardening model) have a great importance for the prediction of the final shapes of sheet metal. However, the predicted springback accuracy of aluminum alloy sheet metal is not still good due to their complicated plastic deformation behaviors.In the present research, the springback deformation of aluminum alloy sheet metals were investigated by finite element calculation with consideration of initial anisotropy and the Bauschinger effect. In order to examine the effect of the initial and deformation induced anisotropy on the springback deformation, several types of high accurate yield function and hardening rules are utilized in the present research. The calculated springback by Yoshida 6th yield function [1] and Yoshida-Uemori model [2] shows an excellent agreement with the corresponding experimental data, while the other models underestimate the springback.

An Analysis of Superplastic Forming in a Re-Entrant Shape

2016 ◽  
Vol 838-839 ◽  
pp. 540-545
Author(s):  
G. Kumaresan ◽  
K. Kalaichelvan
Keyword(s):  
Sheet Metal ◽  
Process Parameters ◽  
Polycrystalline Material ◽  
Tensile Ductility ◽  
Superplastic Forming ◽  
Optimum Process ◽  
Sheet Metals ◽  
Metal Fabrication ◽  
Regular Production ◽  
Complex Shapes

Superplasticity is the ability of a polycrystalline material to exhibit, very large elongations without necking prior to failure in generally isotropic manner. Elongations in excess of 400% are usually referred to as Superplasticity. As the limitations of sheet metal fabrication are most often determined by the tensile ductility, superplasticity in sheet metals offers advantages for the forming of complex shapes easily as a regular production process.The focus of the present work is to arrive at the optimum process parameters in the superplastic forming in re-entrant shape of 7075 aluminium alloy, so as to achieve minimum thinning, lesser forming time and reduction in micro cavities.

scholarly journals Numerical and experimental investigation of the effect of process parameters on sheet deformation during the electromagnetic forming of AA6061-T6 alloy

2020 ◽  
Vol 11 (2) ◽  
pp. 329-347
Author(s):  
Zarak Khan ◽  
Mushtaq Khan ◽  
Syed Husain Imran Jaffery ◽  
Muhammad Younas ◽  
Kamran S. Afaq ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Process Parameters ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Sheet Thickness ◽  
Electromagnetic Forming ◽  
Experimental Results ◽  
Thickness Variation ◽  
Fe Model ◽  
Sheet Deformation

Abstract. Electromagnetic forming is a high-speed sheet metal forming technique to form metallic sheets by applying magnetic forces. In comparison to the conventional sheet metal forming process, electromagnetic forming is a process with an extremely high velocity and strain rate, which can be effectively used for the forming of certain difficult-to-form metals. During electromagnetic forming, it is important to recognise the effects of process parameters on the deformation and sheet thickness variation of the sheet metal. This research focuses on the development of a numerical model for aluminium alloy (AA6061-T6) to analyse the effects of three process parameters, namely voltage, sheet thickness and number turns of the coils, on the deformation and thickness variation of the sheet. A two-dimensional fully coupled finite-element (FE) model consisting of an electrical circuit, magnetic field and solid mechanics was developed and used to determine the effect of changing magnetic flux and system inductance on sheet deformation. Experiment validation of the results was performed on a 28 KJ electromagnetic forming system. The Taguchi orthogonal array approach was used for the design of experiments using the three input parameters (voltage, sheet thickness and number of turns of the coil). The maximum error between numerical and experimental values for sheet thickness variation was observed to be 4.9 %. Analysis of variance (ANOVA) was performed on the experimental results. Applied voltage and sheet thickness were the significant parameters, while the number of turns of the coil had an insignificant effect on sheet deformation. The contribution ratio of voltage and sheet thickness was 46.21 % and 45.12 % respectively. The sheet deformation from simulations was found to be in good agreement with the experimental results.

Generation of Cyclic Stress-Strain Curves for Sheet Metals

2000 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
High Strength ◽  
Cyclic Stress ◽  
Bending Moments ◽  
Sheet Metals ◽  
Stress Strain ◽  
Normal Anisotropy ◽  
Material Parameters

Abstract The main objective of this paper is to generate cyclic stress-strain curves for sheet metals so that the springback can be simulated accurately. Material parameters are identified by an inverse method within a selected constitutive model that represents the hardening behavior of materials subjected to a cyclic loading. Three-point bending tests are conducted on sheet steels (mild steel and high strength steel). Punch stroke, punch load, bending strain and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Normal anisotropy and nonlinear isotropic/kinematic hardening are considered. Material parameters are identified by minimizing the normalized error between two bending moments. Micro genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plastic models.

Finite Element Analysis of Metal Flow of Finishing Groove in Hot Continuous Rolling Bar

2012 ◽  
Vol 510 ◽  
pp. 667-672
Author(s):  
Jia Lin Zhou ◽  
Chen Gang Pan ◽  
Xiao Yong Zhang
Keyword(s):  
Strain Distribution ◽  
Metal Flow ◽  
Dimensional Accuracy ◽  
Stress And Strain ◽  
Fe Model ◽  
Element Analysis ◽  
Iron And Steel ◽  
Expansion Angle ◽  
The Stability ◽  
Stress And Strain Distribution

This article established 3D FE model of dual-radius arc finishing groove and tangent expansion angle finishing groove using ANSYS / LS-DYNA software for Wuhan Iron and Steel plant Ф16 hot continuous bar, and analyzed metal flow pattern, stress and strain distribution of two types finishing grooves. The results show that surface stress and strain distribution of dual-radius arc finishing groove have better uniform than them of tangent expansion angle finishing groove, and dual-radius arc finishing groove ensures the stability of the rolled piece in finishing groove, improve the dimensional accuracy and surface quality of rolled finishing product.

scholarly journals A FEA Method for Mathematical Calculation and Prediction Analysis Cross-sectional Ovalization of Tubes under Rotary Straightening

2021 ◽  
Vol 2083 (4) ◽  
pp. 042057
Author(s):  
Ziqian Zhang ◽  
Ying Zhong
Keyword(s):  
Process Parameters ◽  
Element Model ◽  
Simulation Method ◽  
Stress And Strain ◽  
Cross Sectional ◽  
Bending Deformation ◽  
Deformation Stage ◽  
Thin Walled Pipe ◽  
Thin Walled ◽  
Flattening Process

Abstract The section flattening phenomenon (namely Bazier effect) will occur in the large bending deformation stage of thin-walled pipe in the continuous straightening process. The maximum section flattening amount and the residual section flattening amount are important process parameters, which are the basis for calculating the subsequent process parameters of the flattening circle, and directly determine the roundness of the final pipe and the product quality. However, it is hard to be obtained by the theoretical or experimental methods. Therefore, based on the structure and process parameters of the leveler, a finite element model was built to simulate the section flattening process. Then, ANSYS/LS-DYNA software was used to dynamically simulate the bending flattening phenomenon of thin-walled pipe in the continuous straightening process, and the stress and strain nephographic of the flattening deformation zone was obtained. By recording the position curve of the key nodes in the preventing process, the section flattening amount of the thin-walled pipe in the large bending deformation stage in the continuous straightening process was determined. The simulation results show that the dynamic simulation method can effectively predict the section flattening of thin-walled pipe in the process of continuous straightening.

scholarly journals Influence of process parameters on surface roughness and forming time of Al-1100 sheet in incremental sheet metal forming

2019 ◽  
Vol 13 (2) ◽  
pp. 4911-4927
Author(s):  
Swagatika Mohanty ◽  
Srinivasa Prakash Regalla ◽  
Yendluri Venkata Daseswara Rao
Keyword(s):  
Surface Roughness ◽  
Response Surface ◽  
Sheet Metal ◽  
Process Parameters ◽  
Sheet Metal Forming ◽  
Feed Rate ◽  
Metal Forming ◽  
Wall Angle ◽  
Surface Method ◽  
Incremental Sheet Metal Forming

Product quality and production time are critical constraints in sheet metal forming. These are normally measured in terms of surface roughness and forming time, respectively. Incremental sheet metal forming is considered as most suitable for small batch production specifically because it is a die-less manufacturing process and needs only a simple generic fixture. The surface roughness and forming time depend on several process parameters, among which the wall angle, step depth, feed rate, sheet thickness, and spindle speed have a greater impact on forming time and surface roughness. In the present work, the effect of step depth, feed rate and wall angle on the surface roughness and forming time have been investigated for constant 1.2 mm thick Al-1100 sheet and at a constant spindle speed of 1300 rpm. Since the variable effects of these parameters necessitate multi-objective optimization, the Taguchi L9 orthogonal array has been used to plan the experiments and the significance of parameters and their interactions have been determined using analysis of variance (ANOVA) technique. The optimum response has been brought out using response surfaces. Finally, the findings of response surface method have been validated by conducting additional experiments at the intermediate values of the parameters and these results were found to be in agreement with the predictions of Taguchi method and response surface method.

Research on Influence of Process Parameters on Sheet Metal Extrusion Force

2009 ◽  
Vol 16-19 ◽  
pp. 515-519
Author(s):  
Hua Xiang ◽  
Xin Cun Zhuang ◽  
Zhen Zhao
Keyword(s):  
Sheet Metal ◽  
Process Parameters ◽  
Fem Simulation ◽  
Extrusion Process ◽  
Orthogonal Experimental Design ◽  
Extrusion Force ◽  
Influence Of Process Parameters ◽  
Tool Shape ◽  
Simulation And Experiment ◽  
Metal Extrusion

Extrusion force plays a significant role on sheet metal extrusion process. It is characterized by various process parameters including material properties, extrusion ratio, friction, tool shape etc. In this paper, a reasonable FEM model of sheet metal extrusion process was established and validated by comparing the results of simulation and experiment firstly. Based on the reliable model, the effect on extrusion force of various process parameters was investigated with orthogonal experimental design combined FEM simulation. The work presented in this paper has laid certain foundation for further work of modeling and optimizing extrusion force.

Optimization for Stamping Process Parameters of Front Fender Based on Numerical Simulation Technology

2010 ◽  
Vol 102-104 ◽  
pp. 232-236 ◽  
Author(s):  
Zhi Feng Liu ◽  
Qi Zhang ◽  
Wen Tong Yang ◽  
Jian Hua Wang ◽  
Yong Sheng Zhao
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Process Parameters ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Simulation Analysis ◽  
Explicit Method ◽  
Simulation Technology ◽  
Stamping Process ◽  
Automotive Panel

According to the characteristic which is more and difficult to determine about the automotive panel forming factors, based on the dynamic explicit method, taking the typical automobile front fender for example, do the simulation analysis by using of DYNAFORM. On the premise of taking springback factors into account, analog the best stamping process parameters has been optimized from the analysis results after simulation such as sheet metal forming limited drawing(FLD)and sheet metal thinning drawing.

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