Parametric Investigation of Circular and Elliptical Bulge Tests in Warm Hydroforming Process for AA5754-O Sheet

2011 ◽  
Vol 473 ◽  
pp. 594-601 ◽  
Author(s):  
Hasan Gedikli ◽  
Ömer Necati Cora ◽  
Muammer Koç
Keyword(s):  
Coefficient Of Friction ◽  
Sheet Material ◽  
Dome Height ◽  
Bulge Test ◽  
Test Model ◽  
Significant Finding ◽  
Blank Holder ◽  
Hydroforming Process ◽  
Forming Temperature ◽  
Warm Hydroforming

This study numerically investigated the effects of process parameter variations such as blank holder forces (800kN-1200kN), strain rates (0.0013/sec, 0.013/sec, 0.13/sec), coefficient of friction (0.05-0.15), temperature (150 °C, 260 °C) and apex angles (0º, 60º, 90º,120º) on warm hydroforming of AA 5754-O sheet blanks. Warm hydroforming process was simulated through hydraulic bulge test with circular and elliptical die openings. Dome height and sheet thinning were selected as control parameters for formability of AA 5754-O sheet blanks. Results showed that the dome height and formed blank thicknesses did not change significantly with the variation of coefficient of friction and blank holder force. Moreover, increasing forming temperature and non-isothermal conditions yielded slightly better formability. On the other hand, increase in strain rate, and elliptical type of bulge test cavity led to significant decreases in dome height and formed part thinning. Another significant finding was that the elliptical bulge test model and isothermal analyses did not reveal the effect of anisotropy for the sheet material concerned.

Formability of Al6061 Extruded Tube in Warm Hydroforming

2007 ◽  
Vol 340-341 ◽  
pp. 599-604 ◽  
Author(s):  
Young Seon Lee ◽  
Jung Hwan Lee ◽  
M.Y. Lee ◽  
Young Hoon Moon ◽  
T. Ishikawa
Keyword(s):  
Heat Treatment ◽  
Fe Analysis ◽  
Forming Limit ◽  
Bulge Test ◽  
Forming Process ◽  
Treatment Conditions ◽  
Hydroforming Process ◽  
Forming Temperature ◽  
Warm Hydroforming ◽  
Full Annealing

Formability of tube in elevated temperature is essential data to design the warm hydroforming process parameters, such as tube diameter, forming temperature and die geometries. Since the quantitative data of forming limit can be used to predict the failure on forming process, formability data available on the FE analysis is one of the very important information for the optimum design. In this study, the effect of heat treatment conditions and deformation temperature on the formability was investigated for the warm hydroforming of Al6061 tube. Full annealing and T6-treatment are applied for the heat treatment of Al6061 tubes. To evaluate the hydroformability, uni-axial tensile test and bulge test were performed at temperature ranges between room temperature and 300oC. The measured flow stresses were used as input parameters for the simulation of warm hydroforming process. The damage value and strain variation during hydroforming are analysed by FEM. A forming limit based on the ductile fracture criteria has been proposed by combining the results of experimental and FE analysis for the estimation of formability and optimization of warm hydroforming process.

Warm Hydroformability and Mechanical Properties of Pre- and Post- Heat Treated Al6061 Tubes

2007 ◽  
Vol 29-30 ◽  
pp. 87-90 ◽  
Author(s):  
Hyae Kyung Yi ◽  
Jung Hwan Lee ◽  
Young Seon Lee ◽  
Young Hoon Moon
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Room Temperature ◽  
Cost Effective ◽  
Bulge Test ◽  
Axial Tensile ◽  
Heat Treated ◽  
Shaped Tube ◽  
Forming Temperature ◽  
Warm Hydroforming

Warm hydroformability and mechanical properties of pre- and post- heat treated Al6061 tubes were investigated in this study. For the investigation, as-extruded, fully annealed and T6- treated Al 6061 seamless tubes were prepared. To evaluate the hydroformability, uni-axial tensile test and free bulge test were performed at room temperature and 200ÓC. Also mechanical properties of hydroformed part at various pre- and post-heat treatments were evaluated by tensile test. The tensile test specimens were obtained from hexagonal shaped tube hydroformed at 200ÓC forming temperature. As a result, hydroformability of fully annealed tube is 25% higher than that of extruded tube. The tensile strength and elongation were more than 330MPa and 12%, respectively, when hydroformed part was T6 treated after warm hydroforming. However, hydroformed part using T6 pre treated tube represents low elongation, 8%. Therefore, the T6 treatment after hydroforming for as-extruded tube is proved to be the most cost-effective among various processing conditions.

Investigation about the Oil Pressure Rate in the Warm Hydroforming of an Al-Mg Alloy Component

2016 ◽  
Vol 716 ◽  
pp. 963-972
Author(s):  
Gianfranco Palumbo ◽  
Antonio Piccininni ◽  
Pasquale Guglielmi ◽  
Vito Piglionico ◽  
Donato Sorgente ◽  
...  
Keyword(s):  
Strain Rate ◽  
Mg Alloy ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Integration Platform ◽  
Force Profile ◽  
Hydroforming Process ◽  
Cavity Filling ◽  
Warm Hydroforming ◽  
High Level

In this work, the hydroforming process in warm conditions was used for manufacturing an Al-Mg alloy (AA5754) benchmark component displaying different strain levels due to its geometry. The attention was focused on the effect of the rate to increase the forming pressure (PR), strictly related to the strain rate the material is subjected to. In fact, preliminary tensile and Nakajima tests (both at room temperature and in warm conditions) revealed that the mechanical and formability properties of the investigated alloy are strongly affected by the strain rate. Warm Hydroforming tests were conducted in order to investigate both the working temperature and the parameter PR. The Blank Holder Force profile was varied according to an experimentally determined profile able to avoid oil leakages. Experimental results were collected in terms of output variables related to the die cavity filling and to the strain level reached on the component: in such a way a multi-objective optimization could be carried out using the commercial integration platform modeFRONTIER. The best compromise between the high level of the component deformation and the cycle time could be obtained by conducting the warm hydroforming process at the temperature of 250°C and setting the parameter PR equal to 0.1 MPa/sec.

Numerical Simulation Research on Springback Controlling Methods of Aluminum Alloy Panel during Hydroforming

2016 ◽  
Vol 851 ◽  
pp. 163-167
Author(s):  
Dong Yan Lin ◽  
Yi Li
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Orthogonal Experiment ◽  
Blank Holder Force ◽  
Scoring Method ◽  
Simulation Research ◽  
Blank Holder ◽  
Hydroforming Process

The hydroforming process of the aluminum alloy panel was simulated by the software DYNAFORM. The effects of process parameters (blank holder force, depth of panel and height of draw bead) on springback of the aluminum alloy were investigated. The max springback of the panel was analyzed by weighted scoring method. Then the process parameters were synthetically optimized for the max positive and negative springback. The results showed that the height of draw bead affects obviously the comprehensive springback of the panel. The optimization of the process parameters obtained by the orthogonal experiment can effectively reduce the max springback of the panel.

A Comparative Study on Hydraulic Bulge Testing and Analysis Methods

2008 ◽  
Author(s):  
Eren Billur ◽  
Muammer Koc¸
Keyword(s):  
Flow Stress ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Material Behavior ◽  
Biaxial Stress ◽  
Dome Height ◽  
Bulge Test ◽  
Analysis Methods ◽  
Bulge Testing ◽  
Hydraulic Bulge

Hydraulic bulge testing is a material characterization method used as an alternative to tensile testing with the premise of accurately representing the material behavior to higher strain levels (∼70% as appeared to ∼30% in tensile test) in a biaxial stress mode. However, there are some major assumptions (such as continuous hemispherical bulge shape, thinnest point at apex) in hydraulic bulge analyses that lead to uncertainties in the resulting flow stress curves. In this paper, the effect of these assumptions on the accuracy and reliability of flow stress curves is investigated. The goal of this study is to determine the most accurate method for analyzing the data obtained from the bulge testing when continuous and in-line thickness measurement techniques are not available. Specifically, in this study the stress-strain relationships of two different materials (SS201 and Al5754) are obtained based on hydraulic bulge test data using various analysis methods for bulge radius and thickness predictions (e.g., Hill’s, Chakrabarty’s, Panknin’s theories, etc.). The flow stress curves are calculated using pressure and dome height measurements and compared to the actual 3-D strain measurement from a stereo optical and non-contact measurement system ARAMIS. In addition, the flow stress curves obtained from stepwise experiments are compared with the ones from above methods. Our findings indicate that Enikeev’s approach for thickness prediction and Panknin’s approach for bulge radius calculation result in the best agreement with both stepwise experiment results and 3D optical measurement results.

A Time-Dependent Material Model for the Simulation of Hot Gas-Pressure Forming of Magnesium Alloy AZ31

2012 ◽  
Vol 735 ◽  
pp. 198-203 ◽  
Author(s):  
Alexander J. Carpenter ◽  
Eric M. Taleff ◽  
Louis G. Hector ◽  
Jon T. Carter ◽  
Paul E. Krajewski
Keyword(s):  
Experimental Data ◽  
Sheet Material ◽  
Material Model ◽  
Gas Pressure ◽  
Time Dependent ◽  
Dome Height ◽  
Fem Simulations ◽  
Hot Gas ◽  
Magnesium Alloy Az31 ◽  
Az31 Sheet

A time-dependent material constitutive model is developed for the deformation of wrought Mg AZ31 sheet material at 450°C. This material model is used to simulate gas-pressure bulge forming of AZ31 sheet into hemispherical domes. Finite-element-method (FEM) simulations using this material model are compared against experimental data obtained for dome height as a function of forming time under forming conditions identical to those assumed in the simulations. The time-dependent material model predicts experimental dome heights during forming with a quite useful accuracy. The most significant advantage of the time-dependent material model is that it can address the effect of preheating time on forming. Preheating times shorter than ~120 s produce an increase in forming rate. This material model provides a quantitative means of accounting for that effect.

Superplastic Forming Characteristics of a Fine-Grained Cu-Based Shape Memory Alloy

2012 ◽  
Vol 579 ◽  
pp. 22-31
Author(s):  
Chin Chuan Hsu
Keyword(s):  
Superplastic Forming ◽  
Rate Of Change ◽  
Dome Height ◽  
Base Line ◽  
Fine Grained ◽  
Forming Temperature ◽  
Forming Characteristics ◽  
Temperature And Pressure ◽  
Increasing Temperature ◽  
Free Bulging

The influences of temperature and pressure on the blow forming of CuZnAlZr sheet was investigated under free bulging conditions using argon gas. The effects evaluated were the dome height, measured at the dome apex; the specific thickness, the ratio of the actual thickness to the initial thickness; and the thinning factor, the ratio of the actual thickness to the average thickness. The results show that the dome height and the rate of change of dome height with respect to time, dh/dt, increase with increasing temperature and/or pressure. The specific thickness decreases with increasing fractional height (the ratio of the height of a given point above the base line to the height of the apex), and the specific thickness at the apex decreases with increasing temperature and/or pressure as well. The thinning factor decreases with increasing fractional height. Furthermore, this decrease becomes more significant with an increase in either the forming temperature or pressure. The thinning factor at the apex, as a function of the height to base ratio for all conditions falls into the region between m=0.3 and m=0.75 curves.

scholarly journals Modelling Anisotropic Phenomena of Friction of Deep-Drawing Quality Steel Sheets Using Artificial Neural Networks

2021 ◽  
Vol 21 (3) ◽  
pp. 31-42
Author(s):  
Tomasz Trzepieciński ◽  
Hirpa G. Lemu ◽  
Łukasz Chodoła ◽  
Daniel Ficek ◽  
Ireneusz Szczęsny
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Coefficient Of Friction ◽  
Multilayer Perceptron ◽  
Deep Drawing ◽  
Sheet Material ◽  
Rolling Direction ◽  
Steel Sheets ◽  
The Coefficient Of Friction ◽  
Artificial Neural

Abstract This paper presents a method of determining the coefficient of friction in metal forming using multilayer perceptron based on experimental data obtained from the pin-on-disk tribometer. As test material, deep-drawing quality DC01, DC03 and DC05 steel sheets were used. The experimental results show that the coefficient of friction depends on the measured angle from the rolling direction and corresponds to the surface topography. The number of input variables of the artificial neural network was optimized using genetic algorithms. In this process, surface parameters of the sheet, sheet material parameters, friction conditions and pressure force were used as input parameters to train the artificial neural network. Some of the obtained results have pointed out that genetic algorithm can successfully be applied to optimize the training set. The trained multilayer perceptron predicted the value of the friction coefficient for the DC04 sheet. It was found that the tested steel sheet exhibits anisotropic tribological properties. The highest values of the coefficient of friction under dry friction conditions were registered for sheet DC05, which had the lowest value of the yield stress. Prediction results of coefficient of friction by multilayer perceptron were in qualitative and quantitative agreement with the experimental ones.

Deformation Behaviour of Sheet Metals in Laser Assisted Hydroforming Processes

2005 ◽  
Vol 6-8 ◽  
pp. 361-368 ◽  
Author(s):  
Hans Kurt Tönshoff ◽  
J. Bunte ◽  
O. Meier ◽  
L. Engelbrecht
Keyword(s):  
Deformation Behaviour ◽  
Local Heating ◽  
Grain Structure ◽  
Forming Limit ◽  
Bulge Test ◽  
Capital Investments ◽  
Cold Forming ◽  
Small Form ◽  
Work Pressure ◽  
Forming Temperature

Cupping small form elements in hydroforming processes requires high work pressures and clamping forces and thus high capital investments for presses. Localised laser heating used during sheet metal hydroforming processes should reduce the necessary work pressure. By reducing the yield strength and the strain hardening using local heating, small form elements can be formed at very low pressures of 2 MPa, whereas cold forming requires pressures which are 20-50 times higher. Besides the proportion of forming temperature and work pressure, temperature distribution is very important and can be adjusted using a special laser beam forming optic or a scanning processing head. Line network analysises were carried out showing great improvements in the resulting plastic deformation distribution. In order to characterise the general improvement of the material’s formability, forming limit curves (FLC) were generated using the bulge-test. The results approve the extended forming limit of the laser assisted warm cupping process. Moreover, the mechanical properties and the grain structure of the form elements generated were determined. All investigations were carried out for a deep drawing steel, a 5182 aluminium alloy and an AZ31 magnesium alloy.

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